Angiotensin-converting enzyme gene insertion/deletion polymorphism in Kuwaiti children with retinopathy of prematurity.

Retinopathy of prematurity (ROP) is a disease characterized by neovascularization which occurs in infants with short gestational age and low birth weight and can lead to retinal detachment and blindness. In a proportion of ROP cases, the disease progresses to advanced stages despite rigorous intervention. The genotypes for angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism were determined in 181 premature Kuwaiti infants using a polymerase chain reaction (PCR) method. The incidence of different I/D genotypes was compared in ROP cases (n = 74) and non-ROP controls (n = 107) and within 2 subgroups of ROP patients: (1) in which ROP regressed spontaneously (stages 1-3, n = 53), and (2) in which ROP progressed to advanced stages (stages 4 and 5, n = 21). When the ROP cases were considered collectively as one group, the incidence of the DD genotype was almost identical to that of non-ROP controls. The incidence of heterozygous ID genotype was higher in non-ROP controls. The incidence of the II genotype was higher in ROP cases compared to non-ROP controls (p < 0.01). In contrast to this, when ROP cases were divided in 2 subgroups the incidence of the DD genotype was significantly higher in advanced stage ROP cases compared to spontaneously regressing ROP cases (p < 0.04). The incidences of ID and II genotypes were not significantly different amongst the 2 subgroups of ROP patients.