The Relation of Sex of Affected Parent to the Age at Onset of Huntington's Disease

Abstract

Subjects affected with Huntington's disease were ascertained from the literature and their sex, age at onset of symptoms, major neurological sign (choreo-athetosis or rigidity), and sex of affected parent were recorded. The onset ages of 130 rigid subjects had a lognormal distribution, while those of 434 choreic subjects were normally distributed. Regression analysis indicated that there was an inverse relation between paternal descent and the logarithm of the onset age of rigid persons. It was shown that the well-known predominance of paternal cases of early onset is an extrapolation from adulthood of a general effect. No such relation was found for choreic subjects. It is concluded that there are no genetic reasons to support the idea of a distinct juvenile variant of the disorder.