![]() Retinitis pigmentosa is a genetically inherited disease caused by either autosomal dominant, autosomal recessive, or x-linked genes. In the late stage of the disease, central vision can start to decrease, typically to 20/200 or below. Loss of peripheral vision occurs as the disease progresses and can cause tunnel vision (a visual field of less than 10 degrees as measured by a Humphrey visual field test). This occurs because the photoreceptor responsible for seeing in low-light settings (retinal rods) become damaged in retinitis pigmentosa. Patients with night blindness have problems seeing or are clumsy in dimly lit rooms. Typically the first symptom of retinitis pigmentosa is night blindness. Autosomal dominant Retinitis Pigmentosa is the least pervasive of the three, where as X-linked Retinitis Pigmentosa is the most pervasive. Most genes causing retinitis pigmentosa are autosomal recessive. X-linked genes are responsible for determining gender (XX for females and XY for males). The main difference between recessive genes and dominant genes is that in-order to develop the disease, you need two copies (from both parents) of recessive genes, whereas you only need one copy of a dominant gene (from either parent). Mutations in over 50 genes have been shown to cause retinitis pigmentosa and there are three main categories of the disease autosomal dominant, autosomal recessive and x-linked. In other cases, retinitis pigmentosa progresses quickly and can cause severe vision problems early in life. In some instances, retinitis pigmentosa progresses slowly and goes relatively unnoticed (until in later stages of the disease), with atrophying of the retina occurring over a life-span. It affects the peripheral retina first (the outer retina) and progressively moves toward the central retina. Typically the disease begins in childhood or early adulthood and the rate of progression varies between cases. It is one of the most common forms of inherited retinal degenerative conditions, and affects 1 in 3,700 people within the United States. Retinitis Pigmentosa is a group of genetic eye disorders that progressively causes atrophy of the retina and typically affects both eyes. Pigmentosa (black areas) Fundus photo showing atrophy of the retina with visible choroidal vessels (not usually visible)
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