Abstract
The goal of our research is to determine the genes and mutations causing autosomal dominant retinitis pigmentosa (adRP) and related diseases. As is now common knowledge, this deceptively-simple goal is confounded by the exceptional heterogeneity of retinitis pigmentosa and other forms of retinal degeneration. This heterogeneity includes allelic heterogeneity, i.e., different mutations in the same gene causing different clinical phenotypes or modes of inheritance; genetic heterogeneity, i.e., different genes causing similar diseases; and clinical heterogeneity, i.e., the same gene—even the same allele—causing disimilar diseases in different individuals, even within the same family.