Macular hypoplasia and high myopia in 48, xxyy syndrome: a unique case of 48, xxyy syndrome that presents with high myopia and macular dysplasia

Among sex chromosome aneuploidies, 48, XXYY syndrome is a rare variant. This condition is marked by the existence of an additional X and Y chromosome in males, leading to a diverse range of physical, neurocognitive, behavioral, and psychological manifestations. Typical characteristics include a tall stature and infertility. Other phenotypes include congenital heart defects, skeletal anomalies, tremors, obesity, as well as the potential for type 2 diabetes and/or peripheral vascular disease. A 6-year-old boy, who had been experiencing progressive vision deterioration in both eyes for the past two years, presented with a history of poor vision, delayed motor skills. The patient was diagnosed with micropenis in the pediatric outpatient clinic. Sparse hair, an unusually tall stature and craniofacial dysmorphology characterized by ocular hypertelorism, depressed nasal bridge, and epicanthic folds were observed. Comprehensive ophthalmic examination revealed high myopia and grade 3 macular hypoplasia. Diagnostic investigations including karyotype analysis and whole-exome sequencing identified an anomalous male karyotype comprising two X and two Y chromosomes, confirming a diagnosis of 48, XXYY syndrome. This study underscores the rare association of high myopia and grade 3 macular dysplasia with 48, XXYY syndrome. To our knowledge, this case marks the first recorded instance of macular dysplasia in a patient with 48, XXYY syndrome. This novel finding enhances our understanding of this syndrome's phenotypic variability.