Retinitis pigmentosa (RP) is the most common inherited retinal dystrophy, with around 1 in 5000 people affected. There are hundreds of mutations in over 50 genes that have been found to cause retinitis pigmentosa, resulting in many types of RP with varying degrees of severity. Retinitis pigmentosa is a disease affects the rod photoreceptors initially – patients with RP typically experience difficulty with seeing in the dark, or “nyctalopia” (night blindness) as the first symptom, along with diminished visual fields (peripheral vision). This may manifest as difficulty walking or functioning in the dark, problems with driving, or bumping into objects that are not directly looked at. Retinitis pigmentosa is a progressive condition that eventually affects the cone photoreceptors as well in advanced disease, causing loss of central and colour vision. However, it is important to understand not all patients with retinitis pigmentosa have the same disease; depending on the specific gene mutation and pattern of inheritance two patients with RP can have very different symptoms. Sometimes even individuals with the same mutation can be affected to different degrees. Generally patients with the autosomal dominant form of retinitis pigmentosa tend to have a more mild disease and develop symptoms later in life. Patients with autosomal recessive (AR) RP and X-linked (XL) RP may be more severely affected and present at a younger age.
For more information please visit:
http://ghr.nlm.nih.gov/condition/retinitis-pigmentosa