Clinical and genetic characteristics of Mexican Huntington's disease patients.

We report the characteristics of 691 Mexican patients with Huntington's disease (HD). These patients, representing 401 families, constitute the largest series of Mexican HD cases as yet described in the literature. We found the clinical characteristics of these patients to be similar to those of other populations, but we observed a higher frequency of infantile cases, a shorter disease duration and a lower suicide rate. In 626 cases, for which molecular analyses were available, CAG-trinucleotide expansion size ranged from 37-106 repeats. The large number of CAG repeats (19.04 +/- 3.02) in normal alleles and the presence of new mutations suggest that the overall prevalence of HD in the Mexican population could be expected to be within range of, or higher than, that reported for Europeans.