Retinitis pigmentosa

Retinitis pigmentosa (RP) is a group of inherited disorders that cause vision loss. This vision loss is progressive and will typically begin in childhood, starting with the loss of night vision. This is followed by the loss of peripheral vision and eventually central vision will be affected. Many individuals with RP become legally blind in their adult years. Vision loss is variable and there is no way to predict how much vision will be lost and how fast it will happen. There is no cure for RP, though there are an increasing number of optical aids to help see with reducing vision, as well as a number of therapies that are being tested for efficacy with RP at this time. One of the many causes of RP is pathogenic variants in the DHDDS gene.

RP can be inherited in different ways. RP associated with pathogenic variants in the DHDDS gene is inherited in an autosomal recessive manner. This type of inheritance requires the presence of two copies of a pathogenic variant for a person to have the genetic disease. Both parents must be carriers of a pathogenic variant in the gene in order to be at risk to have an affected child. The child must inherit a pathogenic variant from each carrier parent in order to be affected. There is a 1 in 4 chance that a baby will inherit two mutated copies of the gene and be affected when both parents are carriers.

There are generally no signs or symptoms associated with being a carrier for RP. However, the risk to have a child affected with RP is increased. Testing of reproductive partners is recommended for carriers of RP.

RP is estimated to affect 1 in 3,500 to 1 in 4,000 people in the U.S. and Europe. RP associated with the DHDDS gene is more commonly seen in families of Ashkenazi Jewish ancestry.

The following websites may be informative: Genetic Home Reference: Retinitis Pigmentosa (http://ghr.nlm.nih.gov/)

Gene Reviews: Retinitis Pigmentosa Overview (http://www.ncbi.nlm.nih.gov/books/NBK1417/) OMIM: [613861: RETINITIS PIGMENTOSA 59] (http://www.ncbi.nlm.nih.gov/omim)

• Full gene sequencing