Dystonia in a patient with deletion of 18q.

This is the first reported case of dystonia with a partial deletion of the long arm (q) of chromosome 18. Neurologic findings in the 18q- syndrome include mental retardation, seizures, nystagmus, incoordination, tremor, and chorea. A 36-year-old woman with an 18q terminal deletion [karyotype 46,XX,del(18)(q22.2)] had hypothyroidism, diabetes mellitus, borderline intelligence, short stature, short neck, sensorineural hearing loss, and sensorimotor axonal neuropathy. Parents' karyotypes were normal. She had had incoordination and writing difficulty since childhood. Posturing and tremor of the head began at age 16, followed by arm tremors. She had jaw deviation and tremor, neck tremor with retrocollis, involuntary pronation of the right arm, coarse postural and severe action tremor, and tight pen grip with dystonic wrist extension on writing. The 18q- syndrome should be added to the list of genetic causes of secondary dystonia. A karyotype analysis should be considered in secondary dystonias, particularly when there are associated features such as short stature and endocrinopathies.