INTRAFAMILIAL HETEROGENEITY OF MOVEMENT-DISORDERS - REPORT OF 3 CASESIN ONE FAMILY

We report three members of a single family with an apparently autosoma l dominant, nonparoxysmal, hyperkinetic movement disorder with onset i n adolescence. The proband, a 56-year-old woman, manifested dystonia, tremor and myoclonus; one of her daughters exhibited myoclonus with tr emor, and the other demonstrated myoclonus with chorea Inter accompani ed by tremor and dystonia. The slowly progressive but not debilitating symptoms were restricted to the head, arms and hands and were only mo derately affected by alcohol. Laboratory investigations failed to iden tify any abnormality, and linkage analysis excluded the region contain ing the DYT1 locus, indicating that the gene responsible for idiopathi c torsion dystonia was not implicated in this family. While this disor der shares manifestations with myoclonic dystonia, essential myoclonus and benign chorea, the marked intrafamilial heterogeneity and the sex -limited phenotype expressed only in females of two generations appear to be unique.