Normal CAG repeats in the Huntington gene in a family with benign familial chorea.

Benign familial chorea (BFC) is a rare neurological disease with an autosomal dominant transmission. The disorder is characterized by its early onset in childhood, a non-progressive course of choreatic movements and the absence of intellectual impairment. There is one study describing an expanded (CAG)n repeat in the gene IT15 (Huntington) on chromosome 4p (causative for Huntington's chorea) in a family reported to have BFC that was diagnosed on the basis of onset and non-progressive course. We failed to find an expansion of the (CAG)n repeats in an Austrian family having BFC. The three affected individuals of the family had 18-25 CAG repeats. These results indicate that the diagnostic criteria for BFC should include a normal result in the analysis of the (CAG)n repeat region of the Huntington gene.