Tuberous sclerosis: possible modification of phenotypic expression by an unlinked dominant gene.

Abstract

A unique pedigree is presented which shows tuberous sclerosis in 3 generations of a family. Two heterozygotes for the mutant gene were clinically asymptomatic. A genetic model is proposed to explain these findings based upon the segregation of a 2nd unlinked autosomal dominant gene modifying the expression of the gene for tuberous sclerosis.