Retinoschisis juvenile X - linked (X-linked juvenile retinoschisis) - Gen RS1
Juvenile linked retinoschisis X is a genetic eye disease that affects the retina. Damage to the retina affects visual acuity. Generally, juvenile X - linked retinoschisis affects the cells of the macula responsible for sharp central vision, which is required for detailed tasks such as reading, driving and recognizing faces. Retinoschisis linked to juvenile X is a type of a wider disorder called macular degeneration, which involves the disruption in the normal functioning of the macula. Sometimes peripheral vision is affected in people with this condition.
Retinoschisis juvenile X - linked occurs almost exclusively in males and usually is diagnosed when the affected children start school and become apparent vision problems and reading difficulties. In more severe cases, the squint and nystagmus can be seen in childhood. Additional features include strabismus and hyperopia. In rare cases, serious complications such as retinal detachment or vitreous hemorrhage develop. These eye abnormalities can cause vision problems or blindness.
This process is due in most cases to mutations in the RS1 gene, located on the short arm of chromosome X (Xp22.13). This gene encodes retinosquisina protein found in the retina. Retinosquisina is believed to play a role in the development and maintenance of the retina and specialized cells. The protein is probably involved in the organization of cells in the retina by cell adhesion.
They have identified more than 220 mutations in the RS1 gene in people with juvenile linked retinoschisis have been identified X. Although different types of mutations, most of these mutations change retinosquisina specific amino acids in the protein. Different mutations in the RS1 gene affecting the function of the retinosquisina protein in different ways: by altering the three-dimensional structure of the protein, altering its ability to cell adhesion, making the protein is misplaced inside of retinal cells or inhibiting protein coding. The type of dysfunction of the protein depends on the location of the mutation in the gene RS1. Changes in the function of the protein retinosquisina coding or interrupt their role in the maintenance and organization of the retina, resulting in signs and symptoms of the disease.
This process is inherited as a recessive X - linked pattern in males, an altered copy of the gene in each cell is sufficient to express the disease. In women, a mutation would have to happen in both copies of the gene to be expressed alteration. Because it is unlikely that women have two altered copies of this gene, males are affected by X - linked recessive disorders much more frequently than women. A feature of the X - linked inheritance is that fathers can not pass X - linked traits to their children.
Tests performed in IVAMI: in IVAMI perform detection of mutations associated with juvenile X - linked retinoschisis, by complete PCR amplification of the exons of the gene RS1 and subsequent sequencing.
Samples recommended: EDTA blood collected for separation of blood leukocytes, or impregnated sample card with dried blood (IVAMI may mail the card to deposit the blood sample).