Juvenile retinoschisis

Mutations in the RS1 gene cause most cases of juvenile retinoschisis. The RS1 gene provides instructions for producing a protein called retinoschisin, which is found in the retina. Studies suggest that retinoschisin plays a role in the development and maintenance of the retina, perhaps playing a role in cell adhesion (the attachment of cells together).

RS1 gene mutations lead to a reduced amount or complete absence of retinoschisin, which can cause tiny splits (schisis) or tears to form in the retina. This damage often forms a "spoke-wheel" pattern in the macula, which can be seen during an eye examination. In about half of individuals, these abnormalities are seen in the area of the macula, affecting visual acuity. In the other half, the sides of the retina are affected, resulting in impaired peripheral vision.

Some individuals with juvenile retinoschisis do not have a mutation in the RS1 gene. In these individuals, the cause of the disorder is unknown.

Juvenile retinoschisis is inherited in an x-linked recessive pattern. The gene associated with this condition is located on the X chromosome, one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. In females (who have two X chromosomes), a mutation must be present in both copies of the gene to cause the disorder. Males are affected by X-linked recessive disorders much more frequently than females. A striking characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.

In X-linked recessive inheritance, a female with one mutated copy of the gene (mutation) in each cell is called a carrier. She can pass on the mutation, but usually does not experience signs and symptoms of the condition. Carrier women have a 50% chance of passing the mutation to their children, males who inherit the mutation will be affected; females who inherit the mutation will be carriers and will nearly always have normal vision. Carrier testing for at-risk female relatives and prenatal testing for pregnancies at increased risk are possible if the disease-causing mutation in the family is known.

There is no specific treatment for juvenile retinoschisis. Low vision services are designed to benefit those whose ability to function is compromised by impaired vision. Public school systems are mandated by federal law to provide appropriate education for children who have vision impairment. Surgery may be required to address the infrequent complications of vitreous hemorrhage and retinal detachment. Affected individuals should avoid high-contact sports and other activities that can cause head trauma to reduce risk of retinal detachment and vitreous hemorrhage.