Coats' disease of the retina (unilateral retinal telangiectasis) caused by somatic mutation in the NDP gene: a role for norrin in retinal angiogenesis.

Coats disease is characterized by abnormal retinal vascular development (so-called retinal telangiectasis) which results in massive intraretinal and subretinal lipid accumulation (exudative retinal detachment). The classical form of Coats disease is almost invariably isolated, unilateral and seen in males.
A female with a unilateral variant of Coats disease gave birth to a son affected by Norrie disease.
Both carried a missense mutation within the NDP gene on chromosome Xp11. 2 2. Subsequently analysis of the retinas of nine enucleated eyes from males with Coats disease demonstrated in one a somatic mutation in the NDP gene which was not present within non-retinal tissue.
We suggest that Coats telangiectasis is secondary to somatic mutation in the NDP gene which results in a deficiency of norrin (the protein product of the NDP gene) within the developing retina.
This supports recent observations that the protein is critical for normal retinal vasculogenesis.

