Definition

A term that describes when different gene mutations (changes) cause the same disease or condition. Genetic heterogeneity occurs when a single gene has different mutations (allelic heterogeneity) or when there are mutations in different genes (locus heterogeneity), and in both cases the same disease or condition occurs. For example, tuberous sclerosis (an inherited disorder in which tumors form in the kidneys, brain, eyes, heart, lungs, and skin) is caused by having mutations in a gene on chromosome 9 or chromosome 16.