Review: Clinical findings and genetic characterization of children affected with X-linked retinoschisis in the Spanish population.

X-linked retinoschisis (XLRS) is an inherited retinal disorder due to mutations in retinoschisin 1, characterized by impaired central vision secondary to parafoveal cystic cavities and visual field loss by splitting through the retinal nerve fibre layer in the peripheral retina. It is the leading cause of juvenile macular degeneration in males, and currently there is no approved treatment but carbonic anhydrase inhibitors can be used. A retrospective review of the medical records of 17 children with confirmed XLRS seen in the Paediatric Ophthalmology Department of La Paz University Hospital from the 1st of January 2009 to the 1st of June of 2023 was conducted. Complete ophthalmological studies, genetic testing and full-field electroretinogram were performed. Topical brinzolamide was given to patients with foveoschisis, adding oral acetazolamide in those who did not improve with topical treatment alone or with very extensive foveoschisis at diagnosis. Surgical treatment was performed in retinal detahment (RD) or in no clearing hemovitreous cases. Mean age at diagnosis was 5,86 years and the most common reason for consultation was strabismus, followed by RD. The most frequently affected retinal later on Optic coherence tomography was the inner nuclear layer and throughout the follow-up we observed a decrease in central macular thickness. We found some genotype-phenotype correlation in our series and more severe phenotypes if the first amino acid of the protein is affected or in frameshift mutations. We found that medical treatment (topical and oral) improves foveoschisis, and that surgery shows poor outcomes, especially in younger patients.