CRX

More than 20 mutations in the CRX gene have been found to cause cone-rod dystrophy. The problems associated with this condition include a loss of visual sharpness (acuity), an increased sensitivity to light (photophobia), and impaired color vision. These vision problems worsen over time. Cone-rod dystrophy is caused by mutations that occur in one of the two copies of the CRX gene in each cell. CRX gene mutations are responsible for about one-quarter of the cases of a form of the condition called autosomal dominant cone-rod dystrophy. These mutations lead to a reduction in the amount of functional cone-rod homeobox protein that is available to regulate other genes in the retina. As a result, maintenance of the rod and cone cells is insufficient and these cells deteriorate over time, leading to the vision problems characteristic of cone-rod dystrophy. Researchers believe that there is enough cone-rod homeobox protein function to allow for photoreceptor cell differentiation, but long-term maintenance of the cells cannot be sustained.

Several CRX gene mutations have been found to cause different forms of vision loss in different individuals. It is unclear how mutations in the CRX gene can cause different eye disorders.

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