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Retinitis pigmentosa

From SNPedia

Retinitis pigmentosa (RP) is a degenerative disease which can cause vision impairment or blindness, affecting about 1 in 4000 people worldwide. Symptoms include night blindness, the development of tunnel vision, and slowly progressive decreased central vision starting at approximately 20 years of age. See Wikipedia and similiar resources for clinical details.

In terms of genetics, RP is a heterogeneous disease that can be inherited on its own or in combination with other disorders, and there are both dominantly and recessively inherited forms as well, as shown in several databases including ClinVar, OMIM and RetNet. More than 60 genes may harbor RP mutations.GHR

While mutations in the RHO gene are the most common cause of autosomal dominant retinitis pigmentosa, accounting for 20 to 30 percent of all cases, there are ~20 additional genes known to have dominantly inherited mutations. One estimate indicates that 30 to 40% of retinitis pigmentosa cases show autosomal dominant inheritance.[PMID 17113430]

The most common gene involved in recessively inherited RP is USH2A; mutations in this gene are responsible for 10 to 15 percent of all such RP cases. At least 35 other genes have been associated with the autosomal recessive form of the disorder. Perhaps 50 to 60% of retinitis pigmentosa cases are inherited as an autosomal recessive.[PMID 17113430]

Changes in at least six genes are thought to cause the X-linked form of the disorder. Together, mutations in the RPGR and RP2 genes account for most cases of X-linked retinitis pigmentosa.GHR