Orphan Diseases



Charcot-Marie-Tooth disease (CMT) is one of the most common inherited neurological disorders. Overall CMT affects approximately 1 in 2,500 people in the United States (250,000 US citizens). Since this condition is frequently undiagnosed, misdiagnosed or diagnosed very late in life, it should be noted that prevalence may be higher. CMT, also known as hereditary motor and sensory neuropathy or peroneal muscular atrophy, comprises a group of disorders that affect peripheral nerves. The peripheral nerves lie outside the brain and spinal cord and supply the muscles and sensory organs in the limbs. Symptoms of CMT hereditary neuropathy usually begin gradually sometime in adolescence, early adulthood or middle age. The condition affects an equal number of males and females. There is no cure for CMT, but pain killers, physical therapy, occupational therapy, braces, other orthopedic devices and surgery can help relieve some of the symptoms.

NORD Rare Disease Report on CMT


Retinal Diseases

Retinitis pigmentosa (RP) is a group of inherited disorders characterized by progressive peripheral vision loss and night vision difficulties (nyctalopia) that can lead to central vision loss. The prevalence of typical RP is reported to be approximately 1 in 4000 in the United States (100,000 patients) and it affects approximately 2,000,000 patients worldwide (prevalence is approximately 1 in 5,000). The age of onset can vary but RP is usually diagnosed in young adulthood, although it can present anywhere from infancy to the mid-30s to 50s. There is no effective treatment for this condition. Some studies have suggested that treatment with antioxidants (such as high doses of vitamin A palmitate) may slow disease progression. However, taking high doses of vitamin A is associated with hepatotoxicity. Several clinical trials are in progress to investigate new therapeutic approaches, including omega-3 fatty acid (Docosahexaenoic acid). Additionally, microchip retinal implants that act like a microscopic video camera are in the early stages of development for treating blindness associated with this and other serious eye conditions.

NORD Rare Disease Report on RP