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Strategy (game theory)
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In game theory, a player's strategy is any of the options he or she can choose in a setting where the outcome depends not only on his own actions but on the action of others.[1] A player's strategy will determine the action the player will take at any stage of the game.
The strategy concept is sometimes (wrongly) confused with that of a move. A move is an action taken by a player at some point during the play of a game (e.g., in chess, moving white's Bishop a2 to b3). A strategy on the other hand is a complete algorithm for playing the game, telling a player what to do for every possible situation throughout the game.
A strategy profile (sometimes called a strategy combination) is a set of strategies for all players which fully specifies all actions in a game. A strategy profile must include one and only one strategy for every player.
Contents
[hide]
1 Strategy set
1.1 Choosing a strategy set
2 Pure and mixed strategies
3 Mixed strategy
3.1 Illustration
3.2 Significance
3.3 A disputed meaning
3.4 Behavior strategy
4 See also
5 References
Strategy set[edit]
A player's strategy set defines what strategies are available for them to play.
A player has a finite strategy set if they have a number of discrete strategies available to them. For instance, in a single game of rock-paper-scissors, each player has the finite strategy set {rock, paper, scissors}.
A strategy set is infinite otherwise. For instance, an auction with mandated bid increments may have an infinite number of discrete strategies in the strategy set {$10, $20, $30, ...}. Alternatively, the cake cutting game has a bounded continuum of strategies in the strategy set {Cut anywhere between zero percent and 100 percent of the cake}.
In a dynamic game, the strategy set consists of the possible rules a player could give to a robot or agent on how to play the game. For instance, in the ultimatum game, the strategy set for the second player would consist of every possible rule for which offers to accept and which to reject.
In a Bayesian game, the strategy set is similar to that in a dynamic game. It consists of rules for what action to take for any possible private information.
Choosing a strategy set[edit]
In applied game theory, the definition of the strategy sets is an important part of the art of making a game simultaneously solvable and meaningful. The game theorist can use knowledge of the overall problem to limit the strategy spaces, and ease the solution.
For instance, strictly speaking in the Ultimatum game a player can have strategies such as: Reject offers of ($1, $3, $5, ..., $19), accept offers of ($0, $2, $4, ..., $20). Including all such strategies makes for a very large strategy space and a somewhat difficult problem. A game theorist might instead believe they can limit the strategy set to: {Reject any offer ≤ x, accept any offer > x; for x in ($0, $1, $2, ..., $20)}.
Pure and mixed strategies[edit]
A pure strategy provides a complete definition of how a player will play a game. In particular, it determines the move a player will make for any situation he or she could face. A player's strategy set is the set of pure strategies available to that player.
A mixed strategy is an assignment of a probability to each pure strategy. This allows for a player to randomly select a pure strategy. Since probabilities are continuous, there are infinitely many mixed strategies available to a player.
Of course, one can regard a pure strategy as a degenerate case of a mixed strategy, in which that particular pure strategy is selected with probability 1 and every other strategy with probability 0.
A totally mixed strategy is a mixed strategy in which the player assigns a strictly positive probability to every pure strategy. (Totally mixed strategies are important for equilibrium refinement such as trembling hand perfect equilibrium.)
Mixed strategy[edit]
Illustration[edit]
A B
A 1, 1 0, 0
B 0, 0 1, 1
Pure coordination game
Consider the payoff matrix pictured to the right (known as a coordination game). Here one player chooses the row and the other chooses a column. The row player receives the first payoff, the column player the second. If row opts to play A with probability 1 (i.e. play A for sure), then he is said to be playing a pure strategy. If column opts to flip a coin and play A if the coin lands heads and B if the coin lands tails, then he is said to be playing a mixed strategy, and not a pure strategy.
Significance[edit]
In his famous paper, John Forbes Nash proved that there is an equilibrium for every finite game. One can divide Nash equilibria into two types. Pure strategy Nash equilibria are Nash equilibria where all players are playing pure strategies. Mixed strategy Nash equilibria are equilibria where at least one player is playing a mixed strategy. While Nash proved that every finite game has a Nash equilibrium, not all have pure strategy Nash equilibria. For an example of a game that does not have a Nash equilibrium in pure strategies, see Matching pennies. However, many games do have pure strategy Nash equilibria (e.g. the Coordination game, the Prisoner's dilemma, the Stag hunt). Further, games can have both pure strategy and mixed strategy equilibria. An easy example is the pure coordination game, where in addition to the pure strategies (A,A) and (B,B) a mixed equilibrium exists in which both players play either strategy with probability 1/2.
A disputed meaning[edit]
During the 1980s, the concept of mixed strategies came under heavy fire for being "intuitively problematic".[2] Randomization, central in mixed strategies, lacks behavioral support. Seldom do people make their choices following a lottery. This behavioral problem is compounded by the cognitive difficulty that people are unable to generate random outcomes without the aid of a random or pseudo-random generator.[2]
In 1991,[3] game theorist Ariel Rubinstein described alternative ways of understanding the concept. The first, due to Harsanyi (1973),[4] is called purification, and supposes that the mixed strategies interpretation merely reflects our lack of knowledge of the players' information and decision-making process. Apparently random choices are then seen as consequences of non-specified, payoff-irrelevant exogeneous factors. However, it is unsatisfying to have results that hang on unspecified factors.[3]
A second interpretation imagines the game players standing for a large population of agents. Each of the agents chooses a pure strategy, and the payoff depends on the fraction of agents choosing each strategy. The mixed strategy hence represents the distribution of pure strategies chosen by each population. However, this does not provide any justification for the case when players are individual agents.
Later, Aumann and Brandenburger (1995),[5] re-interpreted Nash equilibrium as an equilibrium in beliefs, rather than actions. For instance, in rock-paper-scissors an equilibrium in beliefs would have each player believing the other was equally likely to play each strategy. This interpretation weakens the predictive power of Nash equilibrium, however, since it is possible in such an equilibrium for each player to actually play a pure strategy of Rock.
Ever since, game theorists' attitude towards mixed strategies-based results have been ambivalent. Mixed strategies are still widely used for their capacity to provide Nash equilibria in games where no equilibrium in pure strategies exists, but the model does not specify why and how players randomize their decisions.
Behavior strategy[edit]
While a mixed strategy assigns a probability distribution over pure strategies, a behavior strategy assigns at each information set a probability distribution over the set of possible actions. While the two concepts are very closely related in the context of normal form games, they have very different implications for extensive form games. Roughly, a mixed strategy randomly chooses a deterministic path through the game tree, while a behavior strategy can be seen as a stochastic path.
The relationship between mixed and behavior strategies is the subject of Kuhn's theorem. The result establishes that in any finite extensive-form game with perfect recall, for any player and any mixed strategy, there exists a behavior strategy that, against all profiles of strategies (of other players), induces the same distribution over terminal nodes as the mixed strategy does. The converse is also true.
A famous example of why perfect recall is required for the equivalence is given by Piccione and Rubinstein (1997) with their Absent-Minded Driver game.
See also[edit]
Nash equilibrium
Haven (graph theory)
Evolutionarily stable strategy
References[edit]
Jump up ^ Ben Polak Game Theory: Lecture 1 Transcript ECON 159, 5 September 2007, Open Yale Courses.
^ Jump up to: a b Aumann, R. (1985). "What is Game Theory Trying to accomplish?" (PDF). In Arrow, K.; Honkapohja, S. Frontiers of Economics. Oxford: Basil Blackwell. pp. 909–924.
^ Jump up to: a b Rubinstein, A. (1991). "Comments on the interpretation of Game Theory". Econometrica. 59 (4): 909–924. JSTOR 2938166.
Jump up ^ Harsanyi, John (1973). "Games with randomly disturbed payoffs: a new rationale for mixed-strategy equilibrium points". Int. J. Game Theory. 2: 1–23. doi:10.1007/BF01737554.
Jump up ^ Aumann, Robert; Brandenburger, Adam (1995). "Epistemic Conditions for Nash Equilibrium". Econometrica. The Econometric Society. 63 (5): 1161–1180. doi:10.2307/2171725. JSTOR 2171725.
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Definitions
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Escalation of commitment
Graphical game
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Simultaneous action selection
Solved game
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Dictator game
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Fair cake-cutting
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Guess 2/3 of the average
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Trust game
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Theorems
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Nash's theorem
Purification theorem
Zermelo's theorem
Folk theorem
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Arrow's impossibility theorem
Key
figures
Albert W. Tucker
Amos Tversky
Ariel Rubinstein
Claude Shannon
Daniel Kahneman
David K. Levine
David M. Kreps
Donald B. Gillies
Drew Fudenberg
Eric Maskin
Harold W. Kuhn
Herbert Simon
Hervé Moulin
Jean Tirole
Jean-François Mertens
John Harsanyi
John Maynard Smith
Antoine Augustin Cournot
John Nash
John von Neumann
Kenneth Arrow
Kenneth Binmore
Leonid Hurwicz
Lloyd Shapley
Melvin Dresher
Merrill M. Flood
Oskar Morgenstern
Paul Milgrom
Peyton Young
Reinhard Selten
Robert Axelrod
Robert Aumann
Robert B. Wilson
Roger Myerson
Samuel Bowles
Thomas Schelling
William Vickrey
See also
All-pay auction
Alpha–beta pruning
Bertrand paradox
Bounded rationality
Combinatorial game theory
Confrontation analysis
Coopetition
Glossary of game theory
List of game theorists
List of games in game theory
No-win situation
Topological game
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Greater Antilles
From Wikipedia, the free encyclopedia
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Greater Antilles
Grandes Antilles (in French)
Antillas Mayores (in Spanish)
Region of the Caribbean

Location within the Caribbean.
Island States
6[show]
Cayman Islands
Cuba
Dominican Republic
Haiti
Jamaica
Puerto Rico
Area
• Total
207,411 km2 (80,081 sq mi)
Population (2014)
• Total
38,400,500
• Density
171.45/km2 (444.1/sq mi)
Demonym(s)
Greater Antillean
Time zones
EST: UTC-5/EDT: UTC-4
AST: UTC-4/ADT: UTC-3
The Greater Antilles is a grouping of the larger islands in the Caribbean Sea: Cuba, Hispaniola (containing Haiti and the Dominican Republic), Puerto Rico, Jamaica, and the Cayman Islands.
The Greater Antilles constitute nearly 90% of the land mass of the entire West Indies,[1] as well as over 90% of its population. The remainder of the land belongs to the archipelago of the Lesser Antilles, which is a chain of islands to the east (running north-south and encompassing the eastern edge of the Caribbean Sea where it meets the Atlantic Ocean) and south (running east-west off the northern coast of South America).
The word Antilles originated in the period before the European conquest of the New World - Europeans used the term Antilia as one of the mysterious lands featured on medieval charts, sometimes as an archipelago, sometimes as continuous land of greater or lesser extent, its location fluctuating in mid-ocean between the Canary Islands and Eurasia.
The Lucayan Archipelago is not considered to be a part of the Antilles archipelagoes but rather of the North Atlantic.
Contents
[hide]
1 Countries
2 References
3 Further reading
4 External links
Countries[edit]
Name
Area
(km²)
Population
(1 July 2005 est.)
Population density
(per km²)
Capital
Cayman Islands (UK) 7002264000000000000♠264 7004548780000000000♠54,878 207.9 George Town
Cuba 7005110860000000000♠110,860 7007113466700000000♠11,346,670 102.4 Havana
Dominican Republic 7004484420000000000♠48,442 7006895003400000000♠8,950,034 183.7 Santo Domingo
Haiti 7004277500000000000♠27,750 7006812162200000000♠8,121,622 292.7 Port-au-Prince
Jamaica 7004109910000000000♠10,991 7006273183200000000♠2,731,832 248.6 Kingston
Puerto Rico (US) 7003910400000000000♠9,104 7006391663200000000♠3,916,632 430.2 San Juan
Total
7005207411000000000♠207,411 7007350667900000000♠35,066,790 169.05
References[edit]
Geography portal
Caribbean portal
Cuba portal
Dominican Republic portal
Haiti portal
Jamaica portal
Puerto Rico portal
United Kingdom portal
Jump up ^ "Greater Antilles". Encyclopædia Britannica. Retrieved 28 May 2015.
Further reading[edit]
Cohen, S.; Groene, J.; Werner, L.; Vladimir, U.; Williams, D.; Walter, C.; Hiller, H.L. (1997). Caribbean: The Greater Antilles, Bermuda, Bahamas. Explore the world Nelles guide. Nelles Verlag. ISBN 978-3-88618-403-3. 254 pages.
University, J.R.P.B.S.S. (1995). Anolis Lizards of the Caribbean : Ecology, Evolution, and Plate Tectonics: Ecology, Evolution, and Plate Tectonics. Oxford Series in Ecology and Evolution. Oxford University Press, USA. p. 88. ISBN 978-0-19-536191-9.
Rogozinski, Jan. A Brief History of the Caribbean. New York: Facts on File, 1992.
External links[edit]
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Coordinates: 21°59′N 79°02′W / 21.983°N 79.033°W / 21.983; -79.033
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Fragile X syndrome
From Wikipedia, the free encyclopedia
Jump to: navigation, search
Fragile X syndrome
Synonyms
Martin-Bell syndrome,[1]
Escalante syndrome
Boy with fragile X syndrome
Specialty
Medical genetics, pediatrics, psychiatry
Symptoms
Intellectual disability, long and narrow face, large ears, flexible fingers, large testicles[1]
Complications
Autism features, seizures[1]
Usual onset
Noticeable by age 2[1]
Duration
Lifelong[2]
Causes
Genetic (X-linked dominant)[1]
Diagnostic method
Genetic testing[2]
Treatment
Supportive care, early interventions[2]
Frequency
1 in 4,000 (males), 1 in 8,000 (females)[1]
[edit on Wikidata]
Fragile X syndrome (FXS) is a genetic disorder.[1] Symptoms often include mild to moderate intellectual disability.[1] Physical features may include a long and narrow face, large ears, flexible fingers, and large testicles.[1] About a third of people have features of autism such as problems with social interactions and delayed speech.[1] Hyperactivity is common and seizures occur in about 10%.[1] Males are usually more affected than females.[1]
Fragile X syndrome is typically due to an expansion of the CGG triplet repeat within the Fragile X mental retardation 1 (FMR1) gene on the X chromosome.[1] This results in not enough fragile X mental retardation protein (FMRP), which is required for normal development of the connection between neurons.[1] Diagnosis is by genetic testing to determine the number of CGG repeats in the FMRI gene.[3] Normal is between 5 and 40 repeats, fragile X syndrome occurs with more than 200, and a premutation is said to be present when a middle number of repeats occur.[1] Testing for premutation carriers may allow for genetic counseling.[3]
There is no cure.[2] Early intervention is recommended as it provides the most opportunity for developing a full range of skills.[4] These interventions may include special education, speech therapy, physical therapy, or behavioral therapy.[2][5] Medications may be used to treat associated seizures, mood problems, or ADHD.[6] Fragile X syndrome occurs in about 1 in 4,000 males and 1 in 8,000 females.[1]
Contents
[hide]
1 Signs and symptoms
1.1 Physical phenotype
1.2 Intellectual development
1.3 Autism
1.4 Social interaction
1.5 Psychiatric
1.6 Hypersensitivity and repetitive behavior
1.7 Vision
1.8 Neurological
1.9 Working memory
1.10 Fertility
2 Causes
2.1 Inheritance
3 Pathophysiology
4 Diagnosis
5 Management
5.1 Medication
6 Prognosis
7 Research
8 History
9 References
10 External links
Signs and symptoms[edit]
Prominent characteristics of the syndrome include an elongated face, large or protruding ears, and low muscle tone.
Most young children do not show any physical signs of FXS.[7] It is not until puberty that physical features of FXS begin to develop.[7] Aside from intellectual disability, prominent characteristics of the syndrome may include an elongated face, large or protruding ears, flat feet, larger testes (macroorchidism), and low muscle tone.[8][9] Recurrent otitis media (middle ear infection) and sinusitis is common during early childhood. Speech may be cluttered or nervous. Behavioral characteristics may include stereotypic movements (e.g., hand-flapping) and atypical social development, particularly shyness, limited eye contact, memory problems, and difficulty with face encoding. Some individuals with fragile X syndrome also meet the diagnostic criteria for autism.
Males with a full mutation display virtually complete penetrance and will therefore almost always display symptoms of FXS, while females with a full mutation generally display a penetrance of about 50% as a result of having a second, normal X chromosome.[10] Females with FXS may have symptoms ranging from mild to severe, although they are generally less affected than males.
Physical phenotype[edit]
Large, protruding ears (both)
Long face (vertical maxillary excess)
High-arched palate (related to the above)
Hyperextensible finger joints
Hyperextensible ('double-jointed') thumbs
Flat feet
Soft skin
Postpubescent macroorchidism (large testicles in men after puberty)[11]
Hypotonia (low muscle tone)[12]
Intellectual development[edit]
Individuals with FXS may present anywhere on a continuum from learning disabilities in the context of a normal intelligence quotient (IQ) to severe intellectual disability, with an average IQ of 40 in males who have complete silencing of the FMR1 gene.[9] Females, who tend to be less affected, generally have an IQ which is normal or borderline with learning difficulties. The main difficulties in individuals with FXS are with working and short-term memory, executive function, visual memory, visual-spatial relationships, and mathematics, with verbal abilities being relatively spared.[9][13]
Data on intellectual development in FXS are limited. However, there is some evidence that standardized IQ decreases over time in the majority of cases, apparently as a result of slowed intellectual development. A longitudinal study looking at pairs of siblings where one child was affected and the other was not found that affected children had an intellectual learning rate which was 55% slower than unaffected children.[13]
When both autism and FXS are present, a greater language deficit and lower IQ is observed as compared to children with only FXS.[14]
Autism[edit]
Fragile X syndrome co-occurs with autism in many cases and is a suspected genetic cause of the autism in these cases.[8][15] This finding has resulted in screening for FMR1 mutation to be considered mandatory in children diagnosed with autism.[8] Of those with fragile X syndrome, prevalence of concurrent autism spectrum disorder (ASD) has been estimated to be between 15 and 60%, with the variation due to differences in diagnostic methods and the high frequency of autistic features in individuals with fragile X syndrome not meeting the DSM criteria for an ASD.[15]
Although individuals with FXS have difficulties in forming friendships, those with FXS and ASD characteristically also have difficulties with reciprocal conversation with their peers. Social withdrawal behaviors, including avoidance and indifference, appear to be the best predictors of ASD in FXS, with avoidance appearing to be correlated more with social anxiety while indifference was more strongly correlated to severe ASD.[15] When both autism and FXS are present, a greater language deficit and lower IQ is observed as compared to children with only FXS.[14]
Genetic mouse models of FXS have also been shown to have autistic-like behaviors.[16][17][18][19][20]
Social interaction[edit]
FXS is characterized by social anxiety, including poor eye contact, gaze aversion, prolonged time to commence social interaction, and challenges forming peer relationships.[21] Social anxiety is one of the most common features associated with FXS, with up to 75% of males in one series characterized as having excessive shyness and 50% having panic attacks.[15] Social anxiety in individuals with FXS is related to challenges with face encoding, the ability to recognize a face that one has seen before.[22]
It appears that individuals with FXS are interested in social interaction and display greater empathy than groups with other causes of intellectual disability, but display anxiety and withdrawal when placed in unfamiliar situations with unfamiliar people.[15][21] This may range from mild social withdrawal, which is predominantly associated with shyness, to severe social withdrawal, which may be associated with co-existing autism spectrum disorder.[15]
Females with FXS frequently display shyness, social anxiety and social avoidance or withdrawal.[9] In addition, premutation in females has been found to be associated with social anxiety.
Individuals with FXS show decreased activation in the prefrontal regions of the brain.
Psychiatric[edit]
Attention deficit hyperactivity disorder (ADHD) is found in the majority of males with FXS and 30% of females, making it the most common psychiatric diagnosis in those with FXS.[8][21] Hyperactivity and disruptive behavior peak in the preschool years and then gradually decline with age, although inattentive symptoms are generally lifelong.[21]
Aside from the characteristic social phobia features, a range of other anxiety symptoms are very commonly associated with FXS, with symptoms typically spanning a number of psychiatric diagnoses but not fulfilling any of the criteria in full.[21] Behaviors such as hand flapping and biting, as well as aggression, can be an expression of anxiety. Although only a minority will meet the criteria for obsessive–compulsive disorder (OCD), a significant majority will feature obsessive-type symptoms. However, as individuals with FXS generally find these behaviors pleasurable, unlike individuals with OCD, they are more frequently referred to as stereotypic behaviors.
Mood symptoms in individuals with FXS rarely meet diagnostic criteria for a major mood disorder as they are typically not of sustained duration.[21] Instead, these are usually transient and related to stressors, and may involve labile (fluctuating) mood, irritability, self-injury and aggression.
Individuals with fragile X-associated tremor/ataxia syndrome (FXTAS) are likely to experience combinations of dementia, mood, and anxiety disorders. Males with the FMR1 premutation and clinical evidence of FXTAS were found to have increased occurrence of somatization, obsessive–compulsive disorder, interpersonal sensitivity, depression, phobic anxiety, and psychoticism.[23]
Hypersensitivity and repetitive behavior[edit]
Children with fragile X have very short attention spans, are hyperactive, and show hypersensitivity to visual, auditory, tactile, and olfactory stimuli. These children have difficulty in large crowds due to the loud noises and this can lead to tantrums due to hyperarousal. Children with FXS pull away from light touch and can find textures of materials to be irritating. Transitions from one location to another can be difficult for children with FXS. Behavioral therapy can be used to decrease the child’s sensitivity in some cases.[12]
Perseveration is a common communicative and behavioral characteristic in FXS. Children with FXS may repeat a certain ordinary activity over and over. In speech, the trend is not only in repeating the same phrase but also talking about the same subject continually. Cluttered speech and self-talk are commonly seen. Self-talk includes talking with oneself using different tones and pitches.[12]
Vision[edit]
Ophthalmologic problems include strabismus. This requires early identification to avoid amblyopia. Surgery or patching are usually necessary to treat strabismus if diagnosed early. Refractive errors in patients with FXS are also common.[14]
Neurological[edit]
Individuals with FXS are at a higher risk of developing seizures, with rates between 10% and 40% reported in the literature.[24] In larger study populations the frequency varies between 13% and 18%,[9][24] consistent with a recent survey of caregivers which found that 14% of males and 6% of females experienced seizures.[24] The seizures tend to be partial, are generally not frequent, and are amenable to treatment with medication.
Individuals who are carriers of premutation alleles are at risk for developing fragile X-associated tremor/ataxia syndrome (FXTAS), a progressive neurodegenerative disease.[10][25] It is seen in approximately half of male carriers over the age of 70, while penetrance in females is lower. Typically, onset of tremor occurs in the sixth decade of life, with subsequent progression to ataxia (loss of coordination) and gradual cognitive decline.[25]
Working memory[edit]
From their 40s onward, males with FXS begin developing progressively more severe problems in performing tasks that require the central executive of working memory. Working memory involves the temporary storage of information 'in mind', while processing the same or other information. Phonological memory (or verbal working memory) deteriorates with age in males, while visual-spatial memory is not found to be directly related to age. Males often experience an impairment in the functioning of the phonological loop. The CGG length is significantly correlated with central executive and the visual–spatial memory. However, in a premutation individual, CGG length is only significantly correlated with the central executive, not with either phonological memory or visual–spatial memory.[26]
Fertility[edit]
About 20% of women who are carriers for the fragile X premutation are affected by fragile X-related primary ovarian insufficiency (FXPOI), which is defined as menopause before the age of 40.[10][25] The number of CGG repeats correlates with penetrance and age of onset.[10] However premature menopause is more common in premutation carriers than in women with the full mutation, and for premutations with more than 100 repeats the risk of FXPOI begins to decrease.[27] Fragile X-associated primary ovarian insufficiency (FXPOI) is one of three Fragile X-associated Disorders (FXD) caused by changes in the FMR1 gene.FXPOI affects female premutation carriers of Fragile X syndrome, which is caused by the FMR1 gene, when their ovaries are not functioning properly. Women with FXPOI may develop menopause-like symptoms but they are not actually menopausal. Women with FXPOI can still get pregnant in some cases because their ovaries occasionally release viable eggs.[28]
Causes[edit]
Location of FMR1 gene on the X chromosome.
Fragile X syndrome is a genetic disorder which occurs as a result of a mutation of the fragile X mental retardation 1 (FMR1) gene on the X chromosome, most commonly an increase in the number of CGG trinucleotide repeats in the 5' untranslated region of FMR1.[10][25] Mutation at that site is found in 1 out of about every 2000 males and 1 out of about every 259 females. Incidence of the disorder itself is about 1 in every 3600 males and 1 in 4000–6000 females.[29] Although this accounts for over 98% of cases, FXS can also occur as a result of point mutations affecting FMR1.[10][25]
In unaffected individuals, the FMR1 gene contains 5–44 repeats of the sequence CGG, most commonly 29 or 30 repeats.[10][25][30] Between 45-54 repeats is considered a "grey zone", with a premutation allele generally considered to be between 55 and 200 repeats in length. Individuals with fragile X syndrome have a full mutation of the FMR1 allele, with over 200 CGG repeats.[8][30][31] In these individuals with a repeat expansion greater than 200, there is methylation of the CGG repeat expansion and FMR1 promoter, leading to the silencing of the FMR1 gene and a lack of its product.
This methylation of FMR1 in chromosome band Xq27.3 is believed to result in constriction of the X chromosome which appears 'fragile' under the microscope at that point, a phenomenon that gave the syndrome its name. One study found that FMR1 silencing is mediated by the FMR1 mRNA. The FMR1 mRNA contains the transcribed CGG-repeat tract as part of the 5' untranslated region, which hybridizes to the complementary CGG-repeat portion of the FMR1 gene to form an RNA·DNA duplex.[32]
Inheritance[edit]
Fragile X syndrome has traditionally been considered an X-linked dominant condition with variable expressivity and possibly reduced penetrance.[9] However, due to genetic anticipation and X-inactivation in females, the inheritance of Fragile X syndrome does not follow the usual pattern of X-linked dominant inheritance and some scholars have suggested discontinuing labeling X-linked disorders as dominant or recessive.[33] Females with full FMR1 mutations may have a milder phenotype than males due to variability in X-inactivation.
Before the FMR1 gene was discovered, analysis of pedigrees showed the presence of male carriers who were asymptomatic, with their grandchildren affected by the condition at a higher rate than their siblings suggesting that genetic anticipation was occurring.[10] This tendency for future generations to be affected at a higher frequency became known as the Sherman paradox after its description in 1985.[10][34] Due to this, male children often have a greater degree of symptoms than their mothers.[35]
The explanation for this phenomenon is that male carriers pass on their premutation to all of their daughters, with the length of the FMR1 CGG repeat typically not increasing during meiosis, the cell division that is required to produce sperm.[10][25] Incidentally, males with a full mutation only pass on premutations to their daughters.[25] However, females with a full mutation are able to pass this full mutation on, so theoretically there is a 50% chance that a child will be affected.[25][30] In addition, the length of the CGG repeat frequently does increase during meiosis in female premutation carriers due to instability and so, depending on the length of their premutation, they may pass on a full mutation to their children who will then be affected.
Pathophysiology[edit]
FMRP is found throughout the body, but in highest concentrations within the brain and testes.[8][10] It appears to be primarily responsible for selectively binding to around 4% of mRNA in mammalian brains and transporting it out of the cell nucleus and to the synapses of neurons. Most of these mRNA targets have been found to be located in the dendrites of neurons, and brain tissue from humans with FXS and mouse models shows abnormal dendritic spines, which are required to increase contact with other neurons. The subsequent abnormalities in the formation and function of synapses and development of neural circuits result in impaired neuroplasticity, an integral part of memory and learning.[8][10][36] Wiring changes have long been suspected to be involved in the sensory pathophysiology[37] and most recently a range of circuit alterations have been shown, involving structurally increased local connectivity and functionally decreased long-range connectivity.[38]
In addition, FMRP has been implicated in several signalling pathways that are being targeted by a number of drugs undergoing clinical trials. The group 1 metabotropic glutamate receptor (mGluR) pathway, which includes mGluR1 and mGluR5, is involved in mGluR-dependent long term depression (LTD) and long term potentiation (LTP), both of which are important mechanisms in learning.[8][10] The lack of FMRP, which represses mRNA production and thereby protein synthesis, leads to exaggerated LTD. FMRP also appears to affect dopamine pathways in the prefrontal cortex which is believed to result in the attention deficit, hyperactivity and impulse control problems associated with FXS.[8][10][21] The downregulation of GABA pathways, which serve an inhibitory function and are involved in learning and memory, may be a factor in the anxiety symptoms which are commonly seen in FXS.
Diagnosis[edit]
Cytogenetic analysis for fragile X syndrome was first available in the late 1970s when diagnosis of the syndrome and carrier status could be determined by culturing cells in a folate deficient medium and then assessing for "fragile sites" (discontinuity of staining in the region of the trinucleotide repeat) on the long arm of the X chromosome.[39] This technique proved unreliable, however, as the fragile site was often seen in less than 40% of an individual's cells. This was not as much of a problem in males, but in female carriers, where the fragile site could generally only be seen in 10% of cells, the mutation often could not be visualised.
Since the 1990s, more sensitive molecular techniques have been used to determine carrier status.[39] The fragile X abnormality is now directly determined by analysis of the number of CGG repeats using polymerase chain reaction (PCR) and methylation status using Southern blot analysis.[9] By determining the number of CGG repeats on the X chromosome, this method allows for more accurate assessment of risk for premutation carriers in terms of their own risk of fragile X associated syndromes, as well as their risk of having affected children. Because this method only tests for expansion of the CGG repeat, individuals with FXS due to missense mutations or deletions involving FMR1 will not be diagnosed using this test and should therefore undergo sequencing of the FMR1 gene if there is clinical suspicion of FXS.
Prenatal testing with chorionic villus sampling or amniocentesis allows diagnosis of FMR1 mutation while the fetus is in utero and appears to be reliable.[9]
Early diagnosis of fragile X syndrome or carrier status is important for providing early intervention in children or fetuses with the syndrome, and allowing genetic counselling with regards to the potential for a couple's future children to be affected. Most parents notice delays in speech and language skills, difficulties in social and emotional domains as well as sensitivity levels in certain situations with their children.[40]
Management[edit]
There are no current treatments or cures for the underlying defects of FXS. Management of FXS may include speech therapy, behavioral therapy, sensory integration occupational therapy, special education, or individualised educational plans, and, when necessary, treatment of physical abnormalities. Persons with fragile X syndrome in their family histories are advised to seek genetic counseling to assess the likelihood of having children who are affected, and how severe any impairments may be in affected descendants.[41]
Medication[edit]
Current trends in treating the disorder include medications for symptom-based treatments that aim to minimize the secondary characteristics associated with the disorder. If an individual is diagnosed with FXS, genetic counseling for testing family members at risk for carrying the full mutation or premutation is a critical first-step. Due to a higher prevalence of FXS in boys, the most commonly used medications are stimulants that target hyperactivity, impulsivity, and attentional problems.[9] For co-morbid disorders with FXS, antidepressants such as selective serotonin reuptake inhibitors (SSRIs) are utilized to treat the underlying anxiety, obsessive-compulsive behaviors, and mood disorders. Following antidepressants, antipsychotics such as Risperdal and Seroquel are used to treat high rates of self-injurious, aggressive and aberrant behaviors in this population (Bailey Jr et al., 2012). Anticonvulsants are another set of pharmacological treatments used to control seizures as well as mood swings in 13%–18% of individuals suffering from FXS. Drugs targeting the mGluR5 (metabotropic glutamate receptors) that are linked with synaptic plasticity are especially beneficial for targeted symptoms of FXS.[9] Lithium is also currently being used in clinical trials with humans, showing significant improvements in behavioral functioning, adaptive behavior, and verbal memory. Alongside pharmacological treatments, environmental influences such as home environment and parental abilities as well as behavioral interventions such as speech therapy, sensory integration, etc. all factor in together to promote adaptive functioning for individuals with FXS.[41]
Current pharmacological treatment centers on managing problem behaviors and psychiatric symptoms associated with FXS. However, as there has been very little research done in this specific population, the evidence to support the use of these medications in individuals with FXS is poor.[42]
ADHD, which affects the majority of boys and 30% of girls with FXS, is frequently treated using stimulants.[8] However, the use of stimulants in the fragile X population is associated with a greater frequency of adverse events including increased anxiety, irritability and mood lability.[21] Anxiety, as well as mood and obsessive-compulsive symptoms, may be treated using SSRIs, although these can also aggravate hyperactivity and cause disinhibited behavior.[9][21] Atypical antipsychotics can be used to stabilise mood and control aggression, especially in those with comorbid ASD. However, monitoring is required for metabolic side effects including weight gain and diabetes, as well as movement disorders related to extrapyramidal side effects such as tardive dyskinesia. Individuals with coexisting seizure disorder may require treatment with anticonvulsants.
Prognosis[edit]
A 2013 review stated that life expectancy for FXS was 12 years lower than the general population and that the causes of death were similar to those found for the general population.[43]
Research[edit]
Fragile X syndrome is the most translated neurodevelopmental disorder under study.[44] The increased understanding of the molecular mechanisms of disease in FXS has led to the development of therapies targeting the affected pathways. Evidence from mouse models shows that mGluR5 antagonists (blockers) can rescue dendritic spine abnormalities and seizures, as well as cognitive and behavioral problems, and may show promise in the treatment of FXS.[8][45][46] Two new drugs, AFQ-056 (mavoglurant) and dipraglurant, as well as the repurposed drug fenobam are currently undergoing human trials for the treatment of FXS.[8][47] There is also early evidence for the efficacy of arbaclofen, a GABAB agonist, in improving social withdrawal in individuals with FXS and ASD.[8][15]
In addition, there is evidence from mouse models that minocycline, an antibiotic used for the treatment of acne, rescues abnormalities of the dendrites. An open trial in humans has shown promising results, although there is currently no evidence from controlled trials to support its use.[8]
The first complete DNA sequence of the repeat expansion in someone with the full mutation was generated by scientists in 2012 using SMRT sequencing.[48]
History[edit]
In 1943, James Purdon Martin and Julia Bell described a pedigree of X-linked mental disability, without considering the macroorchidism (larger testicles).[49] In 1969, Herbert Lubs first sighted an unusual "marker X chromosome" in association with mental disability.[50] In 1970, Frederick Hecht coined the term "fragile site". And, in 1985, Felix F. de la Cruz outlined extensively the physical, psychological, and cytogenic characteristics of those afflicted in addition to prospects for therapy.[51] Continued advocacy later won him an honour through the FRAXA Research Foundation in December 1998.[52]
References[edit]
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^ Jump up to: a b c d e "Facts about Fragile X Syndrome". National Center on Birth Defects and Developmental Disabilities Home CDC. 2 February 2017. Archived from the original on 10 May 2017. Retrieved 10 May 2017.
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Jump up ^ "What are the treatments for Fragile X syndrome?". www.nichd.nih.gov. Archived from the original on 2016-11-21. Retrieved 2016-11-21.
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^ Jump up to: a b "What are the symptoms of Fragile X syndrome?". www.nichd.nih.gov. Archived from the original on 2016-11-21. Retrieved 2016-11-21.
^ Jump up to: a b c d e f g h i j k l m n McLennan, Y; Polussa J, Tassone F, Hagerman R. (2011). "Fragile X Syndrome". Current Genomics. 12 (3): 216–224. doi:10.2174/138920211795677886. PMC 3137006  . PMID 22043169. CS1 maint: Multiple names: authors list (link)
^ Jump up to: a b c d e f g h i j k Garber, KB; Visootsak J, Warren ST. (2008). "Fragile X syndrome". European Journal of Human Genetics. 16 (6): 666–72. doi:10.1038/ejhg.2008.61. PMID 18398441.
^ Jump up to: a b c d e f g h i j k l m n Santoro, MR; Bray SM, Warren ST.; Warren, S. T. (2012). "Molecular Mechanisms of Fragile X Syndrome: A Twenty-Year Perspective". Annu. Rev. Pathol. Mech. Dis. 7: 219–45. doi:10.1146/annurev-pathol-011811-132457. PMID 22017584.
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^ Jump up to: a b c d e f g h i Tranfaglia, M (2011). "The psychiatric presentation of fragile x: evolution of the diagnosis and treatment of the psychiatric comorbidities of fragile X syndrome". Dev Neurosci. 33 (5): 337–48. doi:10.1159/000329421. PMID 21893938.
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Jump up ^ Bourgeois, James A.; Cogswell, Jennifer B.; Hessel, David; Zhang, Lin; Ono, Michele Y.; Tassone, Flora; Farzin, Faraz; Brunberg, James A.; Grigsby, Jim; Hagerman, Randi J. (2007). "Cognitive, anxiety and mood disorders in the fragile X-associated tremor/ataxia syndrome". General Hospital Psychiatry. 29 (4): 349–356. doi:10.1016/j.genhosppsych.2007.03.003. PMC 3991490  . PMID 17591512.
^ Jump up to: a b c Berry-Kravis, E; Raspa M, Loggin-Hester L, Bishop E, Holiday D, Bailey Jr DB. (2010). "Seizures in Fragile X Syndrome: Characteristics and Comorbid Diagnoses". Am J Intellect Dev Disabil. 115 (6): 461–72. doi:10.1352/1944-7558-115.6.461. PMID 20945999. CS1 maint: Multiple names: authors list (link)
^ Jump up to: a b c d e f g h i Peprah, E (Dec 2011). "Fragile X Syndrome: The FMR1 CGG Repeat Distribution Among World Populations". Annals of Human Genetics. 76 (2): 178–91. doi:10.1111/j.1469-1809.2011.00694.x. PMC 3288311  . PMID 22188182.
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Jump up ^ Sherman, Stephanie L; Curnow, Eliza C; Easley, Charles A; Jin, Peng; Hukema, Renate K; Tejada, Maria Isabel; Willemsen, Rob; Usdin, Karen (2014). "Use of model systems to understand the etiology of fragile X-associated primary ovarian insufficiency (FXPOI)". Journal of Neurodevelopmental Disorders. 6 (1): 26. doi:10.1186/1866-1955-6-26. ISSN 1866-1947. PMC 4139715  . PMID 25147583.
Jump up ^ Who.int Archived 2012-10-20 at the Wayback Machine.
^ Jump up to: a b c Maddalena, A; Richards C, McGinniss M, Brothman A, Desnick R, Grier R, Hirsch B, Jacky P, McDowell G, Popovich B, Watson M, Wolff D. (2001). "Technical Standards and Guidelines for Fragile X: The First of a Series of Disease-Specific Supplements to the Standards and Guidelines for Clinical Genetics Laboratories of the American College of Medical Genetics". Genetics in Medicine. 3 (3): 200–205. doi:10.1097/00125817-200105000-00010. PMC 3110344  . PMID 11388762. CS1 maint: Multiple names: authors list (link)
Jump up ^ Nolin SL; Brown WT; Glicksman A; Houck, Jr.; Gargano, Alice D.; Sullivan, Amy; Biancalana, Valérie; Bröndum-Nielsen, Karen; Hjalgrim, Helle; Houck, Elke; Kooy, Frank; Longshore, J; MacPherson, J; Mandel, Jean-Louis; Matthijs, Gert; Rousseau, Francois; Steinbach, Peter; Väisänen, Marja-Leena; von Koskull, Harriet; Sherman, Stephanie L. (2003). "Expansion of the fragile X CGG repeat in females with premutation or intermediate alleles". American Journal of Human Genetics. 72 (2): 454–64. doi:10.1086/367713. PMC 379237  . PMID 12529854.
Jump up ^ Colak D, Zaninovic N, Cohen MS, Rosenwaks Z, Yang WY, Gerhardt J, Disney MD, Jaffrey SR; Zaninovic, N; Cohen, M. S.; Rosenwaks, Z; Yang, W. Y.; Gerhardt, J; Disney, M. D.; Jaffrey, S. R. (Feb 28, 2014). "Promoter-bound trinucleotide repeat mRNA drives epigenetic silencing in fragile X syndrome". Science. 343 (6174): 1002–5. Bibcode:2014Sci...343.1002C. doi:10.1126/science.1245831. PMC 4357282  . PMID 24578575. CS1 maint: Multiple names: authors list (link)
Jump up ^ Dobyns, William B.; Filauro, Allison; Tomson, Brett N.; Chan, April S.; Ho, Allen W.; Ting, Nicholas T.; Oosterwijk, Jan C.; Ober, Carole (2004). "Inheritance of most X-linked traits is not dominant or recessive, just X-linked". American Journal of Medical Genetics. 129A (2): 136–43. doi:10.1002/ajmg.a.30123. PMID 15316978.
Jump up ^ Sherman, SL; Jacobs PA, Morton NE, Froster-Iskenius U, Howard-Peebles PN, Nielsen KB, Partington MW, Sutherland GR, Turner G, Watson M. (1985). "Further segregation analysis of the fragile X syndrome with special reference to transmitting males". Hum Genet. 69 (4): 289–99. doi:10.1007/BF00291644. PMID 3838733. CS1 maint: Multiple names: authors list (link)
Jump up ^ Marco, Elysa J.; Skuse, David H. (Dec 2006). "Autism-lessons from the X chromosome". Social Cognitive and Affective Neuroscience. 1 (3): 183–193. doi:10.1093/scan/nsl028. PMC 2555419  . PMID 18985105.
Jump up ^ Bassell GJ, Warren ST; Warren (2008). "Fragile X syndrome: loss of local mRNA regulation alters synaptic development and function". Neuron. 60 (2): 201–14. doi:10.1016/j.neuron.2008.10.004. PMC 3691995  . PMID 18957214.
Jump up ^ Bureau I, Shepherd G, Svoboda K (2008). "Circuit and Plasticity Defects in the Developing Somatosensory Cortex of Fmr1 Knock-Out Mice". The Journal of Neuroscience. 28 (20): 5178–88. doi:10.1523/JNEUROSCI.1076-08.2008. PMID 18480274. CS1 maint: Multiple names: authors list (link)
Jump up ^ Haberl, Matthias G.; Zerbi, Valerio; Veltien, Andor; Ginger, Melanie; Heerschap, Arend; Frick, Andreas (2015-11-01). "Structural-functional connectivity deficits of neocortical circuits in the Fmr1−/y mouse model of autism". Science Advances. 1 (10): e1500775. doi:10.1126/sciadv.1500775. ISSN 2375-2548. Archived from the original on 2015-11-25.
^ Jump up to: a b Hogan, A (16 Jan 2012). "Visualizing carrier status: Fragile X sybndrome and genetic diagnosis since the 1940s". Endeavour. 36 (2): 77–84. doi:10.1016/j.endeavour.2011.12.002. PMID 22257912.
Jump up ^ "How do health care providers diagnose Fragile X syndrome?". www.nichd.nih.gov. Archived from the original on 2016-11-21. Retrieved 2016-11-21.
^ Jump up to: a b Hagerman RJ; Berry-Kravis E; Kaufmann WE; Ono, M. Y.; Tartaglia, N.; Lachiewicz, A.; Kronk, R.; Delahunty, C.; Hessl, D.; Visootsak, J.; Picker, J.; et al. (2009). "Advances in the treatment of fragile X syndrome". Pediatrics. 123 (1): 378–90. doi:10.1542/peds.2008-0317. PMC 2888470  . PMID 19117905.
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Jump up ^ "FRAXA Member Update (three issues: Spring 1999, Summer 1999, Fall 1999)" (PDF) (newsletter). Newburyport, Massachusetts: FRAXA Research Foundation. Archived (PDF) from the original on 2010-12-15. Retrieved 2017-12-14.
External links[edit]
Classification
V · T · D
ICD-10: Q99.2
ICD-9-CM: 759.83
OMIM: 300624
MeSH: D005600
DiseasesDB: 4973
External resources
MedlinePlus: 001668
eMedicine: ped/800
Patient UK: Fragile X syndrome
Orphanet: 908

Wikimedia Commons has media related to Fragile X syndrome.
CDC’s National Center on Birth Defects and Developmental Disabilities
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Pervasive developmental disorders and autism spectrum (F84, 299)
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Rett syndrome)
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21
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18
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13
Trisomy 9
Warkany syndrome 2
8
Cat eye syndrome/Trisomy 22
22
Trisomy 16
Monosomies/deletions
1q21.1 deletion syndrome/1q21.1 duplication syndrome/TAR syndrome
1
Wolf–Hirschhorn syndrome
4
Cri du chat/Chromosome 5q deletion syndrome
5
Williams syndrome
7
Jacobsen syndrome
11
Miller–Dieker syndrome/Smith–Magenis syndrome
17
DiGeorge syndrome
22
22q11.2 distal deletion syndrome
22
22q13 deletion syndrome
22
genomic imprinting
Angelman syndrome/Prader–Willi syndrome (15)
Distal 18q-/Proximal 18q-
X/Y linked
Monosomy
Turner syndrome (45,X)
Trisomy/tetrasomy,
other karyotypes/mosaics
Klinefelter syndrome (47,XXY)
XXYY syndrome (48,XXYY)
XXXY syndrome (48,XXXY)
49,XXXYY
49,XXXXY
Triple X syndrome (47,XXX)
Tetrasomy X (48,XXXX)
49,XXXXX
Jacobs syndrome (47,XYY)
48,XYYY
49,XYYYY
45,X/46,XY
Translocations
Leukemia/lymphoma
Lymphoid
Burkitt's lymphoma t(8 MYC;14 IGH)
Follicular lymphoma t(14 IGH;18 BCL2)
Mantle cell lymphoma/Multiple myeloma t(11 CCND1:14 IGH)
Anaplastic large-cell lymphoma t(2 ALK;5 NPM1)
Acute lymphoblastic leukemia
Myeloid
Philadelphia chromosome t(9 ABL; 22 BCR)
Acute myeloblastic leukemia with maturation t(8 RUNX1T1;21 RUNX1)
Acute promyelocytic leukemia t(15 PML,17 RARA)
Acute megakaryoblastic leukemia t(1 RBM15;22 MKL1)
Other
Ewing's sarcoma t(11 FLI1; 22 EWS)
Synovial sarcoma t(x SYT;18 SSX)
Dermatofibrosarcoma protuberans t(17 COL1A1;22 PDGFB)
Myxoid liposarcoma t(12 DDIT3; 16 FUS)
Desmoplastic small-round-cell tumor t(11 WT1; 22 EWS)
Alveolar rhabdomyosarcoma t(2 PAX3; 13 FOXO1) t (1 PAX7; 13 FOXO1)
Other
Fragile X syndrome
Uniparental disomy
XX male syndrome/46,XX testicular disorders of sex development
Marker chromosome
Ring chromosome
6; 9; 14; 15; 18; 20; 21, 22
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Sex linkage: X-linked disorders
X-linked recessive
Immune
Chronic granulomatous disease (CYBB)
Wiskott–Aldrich syndrome
X-linked severe combined immunodeficiency
X-linked agammaglobulinemia
Hyper-IgM syndrome type 1
IPEX
X-linked lymphoproliferative disease
Properdin deficiency
Hematologic
Haemophilia A
Haemophilia B
X-linked sideroblastic anemia
Endocrine
Androgen insensitivity syndrome/Spinal and bulbar muscular atrophy
KAL1 Kallmann syndrome
X-linked adrenal hypoplasia congenita
Metabolic
Amino acid: Ornithine transcarbamylase deficiency
Oculocerebrorenal syndrome
Dyslipidemia: Adrenoleukodystrophy
Carbohydrate metabolism: Glucose-6-phosphate dehydrogenase deficiency
Pyruvate dehydrogenase deficiency
Danon disease/glycogen storage disease Type IIb
Lipid storage disorder: Fabry's disease
Mucopolysaccharidosis: Hunter syndrome
Purine–pyrimidine metabolism: Lesch–Nyhan syndrome
Mineral: Menkes disease/Occipital horn syndrome
Nervous system
X-linked mental retardation: Coffin–Lowry syndrome
MASA syndrome
Alpha-thalassemia mental retardation syndrome
Siderius X-linked mental retardation syndrome
Eye disorders: Color blindness (red and green, but not blue)
Ocular albinism (1)
Norrie disease
Choroideremia
Other: Charcot–Marie–Tooth disease (CMTX2-3)
Pelizaeus–Merzbacher disease
SMAX2
Skin and related tissue
Dyskeratosis congenita
Hypohidrotic ectodermal dysplasia (EDA)
X-linked ichthyosis
X-linked endothelial corneal dystrophy
Neuromuscular
Becker's muscular dystrophy/Duchenne
Centronuclear myopathy (MTM1)
Conradi–Hünermann syndrome
Emery–Dreifuss muscular dystrophy 1
Urologic
Alport syndrome
Dent's disease
X-linked nephrogenic diabetes insipidus
Bone/tooth
AMELX Amelogenesis imperfecta
No primary system
Barth syndrome
McLeod syndrome
Smith–Fineman–Myers syndrome
Simpson–Golabi–Behmel syndrome
Mohr–Tranebjærg syndrome
Nasodigitoacoustic syndrome
X-linked dominant
X-linked hypophosphatemia
Focal dermal hypoplasia
Fragile X syndrome
Aicardi syndrome
Incontinentia pigmenti
Rett syndrome
CHILD syndrome
Lujan–Fryns syndrome
Orofaciodigital syndrome 1
Craniofrontonasal dysplasia
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Non-Mendelian inheritance: anticipation
Trinucleotide
Polyglutamine (PolyQ), CAG
Dentatorubral-pallidoluysian atrophy
Huntington's disease
Kennedy disease
Spinocerebellar ataxia 1, 2, 3, 6, 7, 17 (Machado-Joseph disease)
Non-polyglutamine
CGG (Fragile X syndrome)
GAA (Friedreich's ataxia)
CTG (Myotonic dystrophy type 1)
CTG (Spinocerebellar ataxia 8)
CAG (Spinocerebellar ataxia 12)
Tetranucleotide
CCTG (Myotonic dystrophy type 2)
Pentanucleotide
ATTCT (Spinocerebellar ataxia 10)
[show]
v
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Disorders of translation and posttranslational modification
Translation
Ribosome: Diamond–Blackfan anemia
FMR1
Fragile X syndrome
Fragile X-associated tremor/ataxia syndrome
Premature ovarian failure 1
Initiation factor: Leukoencephalopathy with vanishing white matter
snRNP: Retinitis pigmentosa 33
Posttranslational modification
Protein folding
Alzheimer's disease
Huntington's disease
Creutzfeldt–Jakob disease
chaperonins: 3-Methylglutaconic aciduria 5
Protein targeting
I-cell disease
Ubiquitin
E1: X-linked spinal muscular atrophy 2
E3: Johanson–Blizzard syndrome
Von Hippel–Lindau disease
3-M syndrome
Angelman syndrome
Deubiquitinating enzyme: Machado–Joseph disease
Aneurysmal bone cyst
Multiple familial trichoepithelioma 1
SUMO
OFC10
Other
Multiple sulfatase deficiency
Hyperproinsulinemia
Ehlers–Danlos syndrome 6
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Chelation of mercury
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Hug machine
Hyperbaric oxygen therapy
Holding therapy
Relationship development intervention
Secretin
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Related
Occupational therapy
Picture Exchange Communication System (PECS)
Social Stories
Speech therapy
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Centers
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Schools
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The Accidental Teacher: Life Lessons from My Silent Son
Aspergirls: Empowering Females with Asperger's Syndrome
Animals in Translation
In a Different Key
Life Animated
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Autism's False Prophets
Freaks, Geeks, and Asperger Syndrome: A User Guide to Adolescence
Like Colour to the Blind
Look Me in the Eye
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Nobody Nowhere
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Son-Rise: The Miracle Continues
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Switched On
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Extreme Love: Autism
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The Mu Rhythm Bluff
The Curious Incident of the Dog in the Night-Time
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Speed of Dark
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For younger people
Everybody Is Different: A Book for Young People Who Have Brothers or Sisters With Autism
Ian's Walk: A Story about Autism
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Rage: A Love Story
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GND: 4324268-6
Retrieved from "https://en.wikipedia.org/w/index.php?title=Fragile_X_syndrome&oldid=819890554"
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