Dentatorubral-pallidoluysian atrophy. Clinical features of a five-generation Danish family.

We describe the first Danish family with dentatorubral-pallidoluysian atrophy (DRPLA), containing 16 clinically affected individuals in five generations. Inheritance is autosomal dominant. The disorder was diagnosed as Huntington's disease (HD), but analysis of the IT15 gene for HD revealed normal alleles. The diagnosis of DRPLA was based on the finding of elongated CAG repeats in the B37 gene on chromosome 12 in affected individuals. The age at onset ranged from 13 to 60 years, with the most severe clinical picture being associated with onset in childhood. Clinical features included varying combinations of dementia, euphoria, visuomotor disturbances, speech problems, ataxia, tremor, epilepsy and involuntary movements presenting as chorea, athetosis, and dystonia. We discuss characteristics of DRPLA that may enable the differentiation from HD on a clinical basis. In conclusion, DRPLA should be considered and DNA analysis is recommended in patients manifesting varying combinations of extrapyramidal and cerebellar symptoms, especially when clinical features show pronounced intrafamilial variability, and dyscoordination, tremor, myoclonus, epilepsy, and euphoria are part of the syndrome.