X-linked Juvenile Retinoschisis
X-linked juvenile retinoschisis (XLRS) is a genetic ocular disease characterized by reduced visual acuity in males due to juvenile macular degeneration.
X-linked juvenile retinoschisis manifests with poor vision and reading difficulties.
In severe cases, nystagmus, full-thickness retinal detachment that leads to impaired vision or blindness.
In advanced stages, vitreous hemorrhage, retinal detachment, and neovascular glaucoma, which may induce severe loss of vision, can be seen. Female carriers rarely have any vision impairment.
Mutations on the RS1 gene (Xp22.2-p22.1), including missense, nonsense, and splice site mutations, deletions, and insertions. RS1 codes for retinoschisin, an adhesive protein that is believed to participate in the structural and functional integrity of the retina.
The diagnosis can be clinically, based on fundus appearance. Fundus examination shows microcystic changes of the macular region of the retina and areas of splitting within the nerve fiber layer, or schisis (spoked-wheel pattern), and vitreous veils.
Electroretinogram (ERG) shows a reduction in the amplitude of the beta-wave and a relative preservation of the negative alpha-wave in scotopic ERG (electronegative rods and mixed ERG) and a normal photopic ERG.
Optical coherence tomography (OCT) shows schisis areas in the macular region. There is also a family history consistent with X-linked inheritance. Molecular genetic analysis by direct sequencing of the RS1 gene detects mutations in approximately 90% of patients.
In X-linked juvenile retinoschisis, vision decreases slowly until adolescence, and then in most cases remains relatively stable during young adulthood. The disease does not progress again until the fouth or fifth decade of life, when a significant decline in visual acuity typically occurs.
Treatment includes periodic ophthalmologic examination to monitor progression of X-linked juvenile retinoschisis. More, patients are informed about possible ophthalmic complications that can be surgically treated (i.e., retinal detachment, vitreous hemorrhage, cataracts or strabismus). Therefore, patient education and close follow-up are the only clinical alternatives to early identification and treatment of vision-threatening complications.