Retinitis pigmentosa and allied diseases: numerous diseases, genes, and inheritance

Retinitis pigmentosa (RP) and allied diseases are heterogeneous clinically and genetically. Here we summarize the retinal cell types involved in these diseases, the large number of genes that cause them, and the variety of inheritance patterns that the affected families display. Special consideration is given to unusual inheritance patterns. The aggregate carrier frequency for recessive RP alleles may be as high as 10%