Coats-like Retinopathy Associated With 18p Deletion Syndrome

This report examines a case of a novel association of Coats-like retinopathy and 18p deletion syndrome (18p-) and proposes a pathogenic mechanism for the association. A 4-year-old boy with 18p- presented with vision loss due to abnormal retinal vasculature associated with macular lipid exudate and exudative retinal detachment. Fluorescein angiography confirmed peripheral capillary nonperfusion, telangiectasias, and exudation. The left eye was normal. The patient was treated with indirect laser panretinal photocoagulation. Examination 6 years post-treatment revealed stable visual acuity at 20/70, with no recurrence of exudation or fluid. A plausible explanation for association of 18p- and Coats-like retinopathy involves overexpression of the homeobox gene <i>DUX4</i>, which can result from 18p deletion. Over-expression of <i>DUX4</i> causes facioscapulohumeral muscular dystrophy (FSHD), a genetic muscle disorder also associated with Coats disease. This case suggests the possibility of a spectrum of findings caused by <i>DUX4</i> overexpression, which may include exudative retinopathy in the absence of systemic FSHD.