Retinitis pigmentosa is usually an isolated problem; in that only the eye is affected. However there are several rare conditions where RP is associated with other problems, these are known as RP syndromes.
These syndromes are caused by specific faulty RP genes and can usually be diagnosed at a retinal clinic, though your ophthalmologist may well also refer you for specialist advice or testing.
If you or a family member are affected by other disabilities or difficulties as well as RP you should make this known to your consultant. RP syndromes are rarer than RP in isolation, and if you need additional support, information, or to be in contact with others who are affected in the same way RP Fighting Blindness and other organisations can make links for you.
Some of the RP syndromes are:
Usher’s Syndrome is RP accompanied by hearing loss. The hearing loss is often present from birth and varies in severity from moderate to profound. Usher syndrome is the commonest cause of people having both hearing and visual loss and thus people with Usher’s Syndrome face great challenges with both spoken and visual communication. There are three types of Usher’s Syndrome. Usher’s Syndrome type 1 and type 2 are the most common types, accounting for about 95% of affected people in the UK. Information about the three types are available on the RP Fighting Blindness website. Further detailed information on Usher’s Syndrome, and support services for deaf-blind people, are also available from the deaf-blind charity Sense.
(Laurence-Moon) Bardet-Biedl Syndrome (LMBBS)
In this condition RP is accompanied by abnormalities of the fingers and/or toes, obesity, kidney disease and sometimes developmental delay and learning difficulties. About a dozen genes have been identified that cause LMBBS. If you are affected you may like to make links with the LMBBS Society.
Bassen-Kornzweig Syndrome (Abetalipoproteinaemia)
In this condition RP is accompanied by 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). You should be referred to a suitable specialist.
In this condition RP is accompanied by hearing loss, neurological problems, heart problems, dry or flaky skin, loss of sense of smell, and oddly shaped red blood cells. Refsum Syndrome is caused by a genetic abnormality in the enzyme that breaks down phytanic acid, a type of fat commonly found in many foods. As a result, toxic levels of the acid build up in the brain, blood, and other tissues including the retina and the diagnosis of Refsum Syndrome can be made with a blood test to check the level of phytanic acid. Although the disease usually appears in early childhood, some people will not develop symptoms until their 40’s or 50’s. Life-long dietary restriction or avoidance of foods that contain phytanic acid, including dairy products and fatty fish, can be very helpful in the treatment of Refsum Syndrome by reducing the chances of the condition worsening and occasionally leading to slight improvement. Further information on Refsum Syndrome is available from http://refsumdisease.org/patients/index.shtml
In Alström Syndrome, RP is accompanied by obesity, hearing loss, diabetes, and heart problems. Abnormalities in the gene, ALMS1, have been identified as the cause of Alström Syndrome. Further detailed information on Alström Syndrome is available from Alstrom Syndrome UK and Alstrom Syndrome International
People with the rare NARP (Neuropathy, Ataxia and Retinitis Pigmentosa) Syndrome have neurological (muscle weakness, epilepsy and memory problems) and balance problems in addition to RP. The condition is inherited by maternal transmission, that is to say that it is passed on by women to both their sons and daughters, though males tend to be more affected than females. Further information on NARP Syndrome is available online at Wikipedia, (http://en.wikipedia.org/wiki/NARP_syndrome) however you should note that this information is publicly maintained and that you should take advice from your consultant above anybody else. If you are aware of any support organisation specialising in NARP Syndrome please let us know at RP Fighting Blindness in order that we can publish details here.