Clinical Insights and Genetic Implications: "A Comprehensive Case Series of Two Siblings with Cohen Syndrome".

INTRODUCTION: Cohen syndrome is a rare autosomal recessive developmental disorder with various clinical manifestations. These include failure to thrive, hypotonia, intellectual disability, pigmentary retinopathy, myopia, nyctalopia, microphthalmia, acquired microcephaly, truncal obesity, joint hypermobility, intermittent neutropenia, and many other less frequent or subtle features. The condition is associated with mutations in the VPS13B (vacuolar protein sorting 13 homolog B) gene, on chromosome 8. Over 150 mutations in VPS13B have been reported in more than 200 patients with Cohen syndrome. Causative mutations include nonsense, missense, indeland splice-site variants. CASE PRESENTATION: We report 2 siblings with Cohen syndrome who lacked the typical myopic phenotype and instead demonstrated significant hyperopia: +5.00-1.00*175 right eye (RE) and +5.00-1.50*180 left eye (LE) for the first case, and +3.00-1.00*180 (RE), +3.00-1.00*10 (LE) for her sister. Comprehensive ophthalmologic evaluation was performed, including fundus photography, optical coherence tomography (OCT), and electroretinography. Relevant literature was reviewed and correlated with their clinical features and genetic findings. This observation underscores the importance of reevaluating the ophthalmic manifestations and genetic spectrum of Cohen syndrome. CONCLUSIONS: To our knowledge, this is the first report of Cohen syndrome cases presenting with hyperopia rather than myopia. Further studies are necessary to establish the full range of ophthalmic presentations and their genetic implications in Cohen syndrome.