Alcohol-responsive myoclonic dystonia in a large family: dominant inheritance and phenotypic variation

Alcohol-responsive myoclonic dystonia is reported in 26 individuals in a six-generation family, thus indicating autosomal dominant inheritance. Twenty affected family members aged between 3 and 56 years were examined on one occasion. Myoclonus in arms, shoulder, and neck distribution was seen in 17, with occasional generalized jerks in 14. Leg dystonia/hemidystonia was seen in two infant cases, writer's cramp in seven, torticollis/retrocollis in two, and finger tremor in three. The onset of myoclonus was regularly reported from 2 to 3 years of age, the onset of leg dystonia/hemidystonia from 6 to 18 months of age, writer's cramp from early school age, and neck dystonia from late teenage. The effect of alcohol had been noted in 10 individuals, and seven of them abused alcohol. Once established, the neurological signs did not progress significantly. Leg dystonia resolved in two juvenile members. Two adult members had recovered from myoclonus: one elderly man and one posthemorrhagic spastic hemiplegic man. Extensive family investigation is necessary to clarify the clinical variation of this autosomal dominant disorder of involuntary movements.