Evidence for a major dominance component in the variation of serum pepsinogen I levels.

We report here a variance component analysis of the distribution of serum pepsinogen I levels in normal individuals, using a maximum-likelihood method on entire pedigrees. The results indicate a broad heritability of 91%, with some 74% being attributed to a dominance component. This is consistent with the hypothesis that the pepsinogen I level in normals is principally determined by the action of major genes, as also seems to be the case for duodenal ulcer patients and families.