Huntington's disease with onset ages greater than 60 years

We examined five patients with late-onset Huntington's disease (HD), who developed chorea as an initial symptom at age 60 or later. The mean disease duration from the onset of chorea was approximately 8 years (range, 2-16 years). All carried expanded HD alleles with 39 or 40 CAG repeats. Cognitive or psychiatric decline was observed in four patients, the mean duration of the disease being approximately 10 years. One of them had been institutionalized in a nursing home undiagnosed for a long time. Late-onset HD patients with shorter repeat expansions may be overlooked in Japan. Non-disabling chorea, mild cognitive or psychiatric decline in such patients are sometimes unrecognized or misunderstood as aging-related phenomena, and do not come to medical attention. Considering the potential genetic risk to younger generations, however, genetic testing on such late-onset HD patients should be conducted with careful genetic counseling and psychological support for their family members.