Patau syndrome

Patau Sydrome, also known as Trisomy 13 or Trisomy D is a problem with the chromosomes. People who suffer from it have an extra copy of chromosome 13. This is usually because of a problem that occurred during meiosis, but it can also be the result of Robertsonian translocation, a common rearrangement of chromosomes in humans. The risk of getting a problem during meiosis increases when women have babies later in life. The average age for this syndrome is at 31 years.
It is the rarest of the three common trisomies. Down syndrome and Edwards syndrome are more common. Patau syndrome affects about one in 25,000 live births.