Norrie Disease

Norrie disease is an inherited disorder that leads to blindness at birth or soon after, hearing loss, and developmental delay. Mutations in the NDP gene on the X chromosome cause Norrie disease. It is inherited in an X-linked recessive pattern. Because of this reason, Norrie disease affects mostly boys. It is not known how often Norrie disease occurs.

Symptoms

Symptoms of Norrie disease may include:

• blindness in both eyes at birth or soon after
• pupils appear white when light is shined on them (leukocoria)
• colored parts of the eyes (irises) may shrink after birth
• eyeballs may shrink after birth
• cloudiness in the lenses of the eyes (cataracts)
• mild to profound hearing loss may develop over time
• developmental delays in motor skills such as sitting up and walking
• mild to moderate mental retardation

Norrie disease may also cause problems with circulation, breathing, digestion, and excretion.

Diagnosis

If the symptoms a child has suggest Norrie disease, an eye doctor (ophthalmologist) will examine the child's eyes. If Norrie disease is present, the ophthalmologist will see an abnormal retina at the back of the eye. The diagnosis can also be confirmed by genetic testing for mutation of the NDP gene on the X chromosome.

Treatment

There is no specific treatment for Norrie disease and no way to stop or reverse the loss of vision and possibly hearing. Medical treatment may be needed for other problems the disease may cause, such as with breathing or digestion. A child with Norrie disease will need special education due to his visual impairment and hearing loss.

_Sources:

""Norrie Disease." Index of Rare Diseases. 7 Apr 2008. National Organization for Rare Disorders. 16 Apr 2008.

Roche, O. "Norrie Disease." Rare Diseases. July 2005. OrphaNet. 16 Apr 2008.

"Norrie Disease." Genetics Home Reference. Apr 2007. National Library of Medicine. 16 Apr 2008.

"Norrie Disease." Index of Conditions. Oct 2005. Contact A Family. 16 Apr 2008.