Norrie disease is caused by a change (mutation) in the NDP gene, which is located on the X chromosome. It is inherited in an X-linked recessive manner. The NDP gene provides instructions for making a protein called norrin, which affects the way cells and tissues develop. In particular, the norrin protein seems to play an important role in the development of retinal cells in the eye. It is also involved in creating a blood supply to tissues of the retina and the inner ear, and the development of other body systems. Mutations in the NDP gene can prevent the norrin protein from working correctly, resulting in the signs and symptoms of Norrie disease.
Last updated: 3/11/2016
What causes autism spectrum disorder (ASD)?
The underlying cause of autism spectrum disorder (ASD) is generally unknown. Scientists suspect that it is a multifactorial condition, meaning that a variety of factors (both genetic and environmental) likely contribute to the development of the condition.
Having older parents (a mother who is 35 or older, and/or a father who is 40 or older when the baby is born)
Having certain genetic conditions (including Down syndrome, fragile X syndrome, and tuberous sclerosis)
Exposure to certain prescriptive medications during pregnancy (such as valproic acid, thalidomide)
Of note, no scientific evidence for a relationship between vaccines and autism has been identified.
Last updated: 12/2/2016
Is the X chromosome associated with autism?
Certain genes on the X chromosome (known as X-linked genes) may play a role in the development of autism spectrum disorders, as several genetic disorders caused by changes in genes on this chromosome share the features of autism. Increasing evidence suggests that genetic influences from the X chromosome play a crucial role in the fact that many more males than females have autism.
Researchers have noted that it is difficult to identify a clear relationship between the influence of any single gene (out of several potential candidates) and any aspect of the signs of autism spectrum disorders. Many experts believe that there are probably other important influences that could be environmental in origin.
Last updated: 11/30/2010
Is there a relationship between Norrie disease and autism?
We were not able to locate any reported cases of individuals diagnosed with both Norrie disease and autism. However, approximately 30-50% of males with Norrie disease have developmental delay, intellectual disability, behavioral abnormalities, or psychosis. These features have also been observed in some individuals with autism.
Last updated: 11/30/2010
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