“…Those first affected were the children of first-cousin marriages: the appearance of the character in the subsequent generation in each pedigree can be explained only by the mating of a homozygous affected with a heterozygous normal, a circumstance indicative of a relatively high rate of heterozygous normals in the population. The family histories of cases described by Schottky (1932), Grunthal and Wenger (1939), van Bogaert, Maere, and de Smedt (1940), who described two cases, and Essen-Moller (1946) all admit of transmission of an autosomal or partially sex-linked dominant gene, there being in each instance a " vertical " distribution ofaffected persons, of whom all had one affected parent so far as could be traced.…”