Objective: To present previously undescribed vitreoretinal findings similar to severe retinopathy of prematurity (ROP) in two siblings (daughter and son) with a thrombophilic disorder, compound heterozygous protein S (PS) deficiency.
Design: Family genotype study and literature review.
Participants: Two unrelated heterozygous PS-deficient parents and their two children with compound heterozygous PS deficiency were studied. The gestational age and birth weight of the daughter were 40 weeks and 3200 g, respectively, and those of the son were 34 weeks and 2150 g, respectively. Three other neonates with homozygous or compound heterozygous PS deficiency and ophthalmologic findings were identified in the literature.
Intervention: The daughter underwent lensectomy-vitrectomy at 48 weeks adjusted age bilaterally. The son underwent therapy developed for severe ROP: laser therapy of the peripheral avascular retina at 39 weeks adjusted age, and bilateral lensectomy-vitrectomy with membrane peel of intravitreous proliferation from the optic disc at 42 weeks adjusted age.
Main outcome measures: The main clinical outcome measures were retinal appearance and functional vision. Genotypes of the family members were determined.
Results: One of the four eyes retained functional vision. A normal-appearing posterior retina, normal scotopic and photopic flash electroretinograms, and a normal flash visual-evoked response were documented from the left eye of the son at 62 weeks adjusted age. The other three eyes had inoperable retinal detachments and no functional vision. The mother had type I PS deficiency and the father had type II PS deficiency. Compound heterozygous PS deficiency was confirmed in both children.
Conclusion: In both children, normal vasculogenesis was interrupted. At 39 weeks adjusted age, the retinal examination of the son revealed extraretinal fibrovascular proliferation at the optic disc (reactivation of the hyaloid system) and in the peripheral retina (interruption of inner retinal vascularization). Patients with homozygous or compound heterozygous PS deficiency may present as infants with severe ROP. The authors' experience suggests that appropriately timed surgical procedures, which are efficacious for ROP, can preserve vision in infants with thrombophilic disorders.