Distinct Ocular Expression in Infants and Children With Down Syndrome in Cairo, Egypt

Abstract

The study establishes the importance of genetic background for the expression of Down syndrome phenotype. To define the ocular manifestations of Down syndrome in infants and children in Cairo, Egypt, a historically isolated region, and compare them with systemic features and with findings in other geographic groups. We prospectively studied the ocular status and systemic features of 90 infants and children with Down syndrome and monitored all patients for 3 years. The complete ophthalmic examinations were performed along with ultrasonography, if media opacities were evident. Thyroid and cardiac status were assessed. An extensive literature search for comparison was performed. Outpatient clinical genetics department at the National Research Centre in Cairo, Egypt. Ocular and systemic manifestations of Down syndrome in infants and children in Cairo, and comparison of these features with patients with this anomaly from other geographic regions and ethnic populations. Fifty-two infants or children (58%) had at least 1 abnormal ocular finding identified at the first visit. Significant refractive errors (in 37 [41%] patients) were the most common. Nasolacrimal duct obstruction, blepharoconjuctivitis, or conjunctivitis was found in 18 (20%), strabismus in 13 (14%), cataract in 5 (6%), nystagmus in 3 (3%), and optic nerve dysplasia in 2 (2%). Brushfield spots were not found. Additional ocular features developed over time. Thirty-six patients (40%) had congenital heart defects, and many (31 [86%]) had associated ocular disorders; a statistically significant correlation with myopia was established. Chromosomal translocations were high. The phenotype in Cairo was distinct. More than half of infants and children with Down syndrome in Cairo had ophthalmic abnormalities; myopia was correlated with congenital heart defects. Comparison of the specific ocular features in our population with those in previous worldwide studies shows differences that may be related to overexpression or polymorphisms of key, modifying genes or other mutations in this historically isolated region along the Nile River. Down syndrome is more common in the highly consanguineous and multiparous Middle Eastern populations, and our Cairo findings underscore regional differences.