Genetic hemochromatosis: Distribution analysis of six laboratory measures of iron metabolism

Six laboratory measures of iron metabolism were studied in a control sample, and a family sample was ascertained on the basis of probands with clinically diagnosed genetic hemochromatosis. The respective distribution of each variable evidenced a mixture of components, presumably arising from the segregation of an HLA-linked locus for hemochromatosis. There were significant differences in the distributional characteristics with respect to sex and genotype-specific variances. These aspects of the data have important implications for subsequent segregation and linkage analyses, which traditionally assume homoscedasticity and homogeneity of the genetic effect.