Types of inherited sight loss

Retinitis pigmentosa (RP) is an inherited eye condition that affects the photoreceptor cells responsible for capturing images from the visual field. These cells line the back of the eye in the region known as the retina.

Leber Congenital Amaurosis (LCA) is a rare genetic eye disease that appears at birth or in the first few months of life.

Choroideremia is a genetic condition that causes progressive vision loss, mostly in males, and is due to degeneration of the specialised light-sensing photoreceptor cells that line the back of the eye.

Stargardt disease is the most common form of inherited juvenile macular degeneration. Progressive vision loss is caused by the death of photoreceptor cells in the central portion of the retina called the macula.

Achromatopsia is a rare hereditary vision disorder resulting in an absence of colour vision along with additional visual problems.

Best disease symptoms usually appear during childhood or early adolescence, but some people may only start experiencing problems later in life. The severity of symptoms can also vary between individuals.

Juvenile macular degeneration is an umbrella term for a series of inherited eye disorders that affect children and young adults.

This very rare condition is associated with a deficiency in the enzyme ornithineaminotransferase.

Cone-rod dystrophy is less common than rod-cone dystrophy with an incidence of approximately 1 in 80,000.

Rod-cone dystrophy is an umbrella term used to describe retinal conditions in which the rod-shaped photoreceptors, found mainly in the peripheral areas of the retina, degenerate ahead of the cone-shaped photoreceptors in the centre.

In this condition RP is accompanied by abnormalities of the fingers and/or toes, obesity, kidney disease and sometimes developmental delay and learning difficulties.

In Alström syndrome, inherited progressive eye disease is accompanied by obesity, hearing loss, diabetes, and heart problems.

People with NARP (Neuropathy, Ataxia and Retinitis Pigmentosa) syndrome have neurological (muscle weakness, epilepsy and memory problems) and balance problems in addition to retinitis pigmentosa.

In Refsum syndrome, visual impairment is accompanied by hearing loss, neurological problems, heart problems, dry or flaky skin, loss of sense of smell, and oddly shaped red blood cells.

Usher syndrome is an inherited condition that affects both hearing and vision. The symptoms of Usher syndrome consist of childhood-onset hearing loss, progressive vision loss caused by degeneration of the retina (retinitis pigmentosa), and sometimes balance problems.

In this condition, retinitis pigmentosa is accompanied by progressive neurological problems, abnormal red blood cells (acanthocytosis) and defective bowel absorption of fat, leading to very low blood levels of cholesterol and absent beta lipoprotein (Abetalipoproteinaemia).