Abstract
Retinopathy of prematurity (ROP) is the most common avoidable cause of blindness and impaired vision among children in developed countries. It is unclear at present why ROP progresses to severe disease in one group of very low birth-weight infants but regresses spontaneously in other infants with similar clinical characteristics. Prevalence of ROP in monozygotic and dizygotic twins and ethnic differences in the prevalence of ROP suggest that genetic predisposition is a probable risk factor. Morphological changes in the retina, such as retinal fold, retinal detachment and cicatrisation, observed in children with advanced ROP are similar to those observed in some children with congenital, genetically determined disorders of the retina, such as familial exudative vitreoretinopathy (FEVR). In this way, the genes responsible for FEVR are likely ‘candidates’ causing ROP. However, the results of recent studies indicate that, although mutations or polymorphisms of frizzle-4 or norrin may play a role in the pathogenesis of ROP, they do not appear to be a major causative factor. Recently, other genes have been suggested as candidate genes for ROP: genes coding for growth factors, pro- and antiinflammatory cytokines, and molecules involved in free radical elimination. This selection has been based on potential involvement in the angiogenesis-regulating mechanisms. Currently, there is no strong evidence supporting the association of any studied gene just mentioned and the risk of advanced ROP. Promising preliminary data concerned with the role of polymorphism in the promotor region of the vascular endothelial growth factor gene have not been confirmed in any recently published study.