4 rare diseases characterized by similar neurodegenerative symptoms. Patients with fragile X tremor/ataxia syndrome (FXTAS), neuronal intranuclear inclusion disease (NIID) and oculopharyngeal myopathy with leukoencephalopathy (OPML) have similar brain MRIs. Patients with oculopharyngodistal myopathy (OPDM) have normal brain scans but muscle tissue that's similar to OPML patients