Cystoid Macular Edema in a 10-Year-Old Boy With Cohen Syndrome

Cohen syndrome is an extremely rare disease with characteristic somatic and multi-system features that severely affect vision. Ophthalmologists must consider Cohen syndrome when developmental delay, high-grade myopia, and retinal dystrophy are present in a child. Here we report a case of Cohen syndrome in a 10-year-old boy presenting with cystoid macular edema (CME), only the second reported case of its kind. This case illustrates the phenotypic variability that can occur in Cohen syndrome, with rare features in addition to CME including trace posterior subcapsular cataracts, growth hormone deficiency, mild vermian hypoplasia, a nasolacrimal cyst, hearing loss, and high-functioning intelligence quotient (IQ). Our patient did not have an identifiable second mutation even after extensive genetic testing, which raises questions about whether the patient has a novel gene variant for the disease or an autosomal dominant mode of inheritance exists for Cohen syndrome. In addition to peripheral vision loss, the rare appearance of macular edema can threaten the remaining vision and requires intervention. This case also demonstrates that, without a high index of suspicion, there can be considerable delay in diagnosing Cohen syndrome. Though little is known about the prevalence of many of the clinical features seen in our case in the Cohen syndrome population, this case raises awareness of the syndrome and the need to recognize various clinical features, perform genetic testing, and direct appropriate treatment to prevent complications and help improve quality of life.