Clinical anticipation in Japanese families of benign adult familial myoclonus epilepsy.

The clinical anticipation in Japanese benign adult familial myoclonus epilepsy (BAFME), defined as earlier onset age of either cortical tremor or generalized seizures or new appearance of those symptoms in the next generation, remains unknown. The onset age and the degree of both cortical tremor and generalized seizures were investigated in nine patients of four BAFME families (mean age: 46.6 ± 18.7 years). Clinical anticipation in the onset age of cortical tremor or generalized seizures was observed in three families, and generalized seizures newly appeared in the next generation in those two families and in another family. Clinical anticipation was observed in four families, which suggests the clinical progression over generation in Japanese BAFME families.