Huntington Disease: No Evidence for Locus Heterogeneity

Abstract A total of 63 families with Huntington disease (HD) were examined for linkage between HD and G8 ( D4S10 ). The families included 57 Caucasian, four Black American, and two Japanese. The combined maximum lod score was 87.69 at θ = 0.04 (99% confidence interval 0.018–0.071). The maximum frequency of recombination was 0.03 in males and 0.05 in females. Fifty-seven families gave positive lod scores; five small families gave mildly negative lod scores. The maximum likelihood estimate of α, the proportion of linked loci, was 1.0 with a lower 99% confidence interval of 0.88. These data suggest that there is only one HD locus, although a second rare locus cannot be ruled out.