What are the other Names for this Condition? (Also known as/Synonyms)

• Congenital X-Linked Retinoschisis
• Degenerative Retinoschisis
• XJR (X-Linked Juvenile Retinoschisis)

What is X-Linked Juvenile Retinoschisis? (Definition/Background Information)

• X-Linked Juvenile Retinoschisis (XJR), as the name suggests, is a genetic disorder that is linked to the X chromosome. In this disorder, the retina splits into two, causing gradual deterioration of vision
• The gene responsible for this condition is known as the RS1 gene, which is defective or reduced in quantity. In a few cases of XJR, however, the RS1 gene is not defective and the exact cause of the disorder is unknown
• The condition is characterized by symmetric, bilateral eye (macular) involvement. The process of the disorder usually starts before the child reaches 10 years of age. Boys get diagnosed with XJR when they start attending school, when bad eyesight leading to reading problems becomes apparent
• Some women, who carry recessive genes on both X-chromosomes, are also reported to be affected by X-Linked Juvenile Retinoschisis. A familial history of XJR is a key risk factor
• The symptoms of X-Linked Juvenile Retinoschisis may be discernible in boys during infancy, and gradually they become apparent in school-age. The symptoms include squinting, involuntary eye movement, poor eyesight, and difficulties in focusing. Retinal detachment or vitreous hemorrhage as a result of XJR could cause complications, such as extremely-impaired vision, and could potentially lead to blindness
• A physician might be able to diagnose X-Linked Juvenile Retinoschisis in infants by detecting cysts in the eye. Typical diagnostic tests include an eye exam to detect the “spoke-wheel” pattern in the macula and checking for leaking blood vessels in the retina. A genetic test may be performed to diagnose XJR and rule out some similar conditions, such as retinitis pigmentosa
• Treatment options for XJR are usually focused on improving the eyesight of the affected individuals. Some individuals may benefit from large print books, high-contrast reading materials, or moving to the front of the classroom, in order to see the board better. In case of retinal detachment or hemorrhages, surgery might be an option. Regular visits to an ophthalmologist are recommended for kids with the disorder
• There is no permanent cure for XJR available at this time. The disease is reported to progress rapidly in the first two decades of an individual’s life, stabilize in adulthood (till about age 50), and decline subsequently. It is recommended that such individuals be given mobility training and low-vision aids to maintain their independence.
• Since contact sports and head injuries might trigger retinal detachment, affected individuals are also advised to refrain from such activities and avoid any head injuries

Who gets X-Linked Juvenile Retinoschisis? (Age and Sex Distribution)

• X-linked Juvenile Retinoschisis exclusively affects boys, in a majority of the cases, since they only have one X- chromosome
• It could potentially occur in girls who have two defective genes; one on each of their chromosome
• The prevalence of XJR in men (or males) worldwide is 1:5,000 to 1:25,000
• No racial or ethnic predilection is observed

What are the Risk Factors for X-Linked Juvenile Retinoschisis? (Predisposing Factors)

The risk factors for X-linked Juvenile Retinoschisis include:

• Family history of the disorder
• Male gender

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your health care provider.

What are the Causes of X-Linked Juvenile Retinoschisis? (Etiology)

X-linked Juvenile Retinoschisis is inherited in an X-linked recessive pattern.

• It occurs due to a mutation in the gene called RS1. Generally, the RS1 gene has instructions to make a retinal protein known as retinoschisin. The RS1 gene codes for this protein and is carried on the X-chromosome. Mutation in RS1 gene results in reduced production of retinoschisin
• Not all cases of X-Linked Juvenile Retinoschisis are caused by a mutation in the RS1 gene. In individuals with XJR where the RS1 gene is normal, the cause of the disease is not known
• X-Linked Juvenile Retinoschisis is usually inherited from unaffected mothers (carriers), who inherit the gene from their fathers. Since the defective, recessive RS1gene is carried on the X-chromosome (males have only one X-chromosome), it is expressed in males. Females are usually carriers of the defect

X-linked recessive: X-linked recessive conditions are traits or disorders that occur when two copies of an abnormal gene are inherited on a sex chromosome (X or Y chromosome). All X-linked recessive traits are fully evident in males, because they have only one copy of the X chromosome. This means that there is no normal gene present to mask the effects of the mutant copy. All males who are affected will pass the mutated gene onto their female offspring, because they must inherit one copy of the X chromosome from each parent. This means that they will be unaffected carriers. Females are rarely affected by X-linked recessive disorders because they have two copies of the X chromosome. In the rare case that they inherit two mutated copies of the gene, they will inherit the condition.

What are the Signs and Symptoms of X-Linked Juvenile Retinoschisis?

• X-Linked Juvenile Retinoschisis is sometimes detected in infants; one may be able to detect squinting and involuntary movement of the eyes
• Small cysts may form in the center of the retina, often giving a ‘spoke wheel pattern,’ which may be detected by the examining physicians
• Development of cysts in the eye and rupturing of blood vessels between the layers of the retina could result in splitting of the retina from its surrounding tissues
• The most common complaints of children with this condition are an inability to see clearly, difficulty in focusing on an object, or involuntary eye movements. This is due to the splitting of the retina and changes in the macula
• In XJR, one’s vision is reported to gradually decrease in the first two decades of life, and then remain stable till about 50 years of age

How is X-Linked Juvenile Retinoschisis Diagnosed?

A physician may request one or more of the following tests and evaluations to arrive at an accurate diagnosis of X-linked Juvenile Retinoschisis:

• Ophthalmological evaluation (eye examination)
• Molecular Testing for RS1 gene: The molecular tests can be performed utilizing various methods, including targeted mutation analysis, sequence analysis, deletion duplication testing, etc.
• Optical coherence tomography (OCT) of the eye
• Intravenous fluorescein angiogram of the eye
• Electro-physiologic testing such as electroretinogram (ERG)
• Fundal examination: Fundus findings are usually present on fundal examination. It might show areas of schisis (splitting of the nerve fiber layer of the retina) in the macula portion of the retina. This finding is called spoke wheel pattern sign

Tests to differentiate between XJR and other conditions that might be present with similar signs and symptoms include:

• Retinitis pigmentosa (RP)
• Goldman-Favre vitreoretinal dystrophy
• Wagner's vitreoretinal dystrophy
• Sticklers syndrome

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of X-Linked Juvenile Retinoschisis?

The following are some complications that could potentially arise from X-Linked Juvenile Retinoschisis:

• Vitreous hemorrhage
• Full-thickness retinal detachment (could occur as a result of sporting activities and head injuries)
• Extremely impaired vision
• Blindness

How is X-Linked Juvenile Retinoschisis Treated?

At this time, no permanent treatment for X-Linked Juvenile Retinoschisis exists. Treatments are generally focused on symptoms’ relief and aiding patients lead fairly independent lives. These include:

• Surgery in case of hemorrhage and retinal detachments
• Regular annual visit to a pediatric ophthalmologist or retina specialist
• Large print books help in reading
• Moving kids with vision problems to the front of the classroom
• Study materials with high contrast to aid in reading
• Mobility training, to help the patients manage extremely poor eyesight
• Low-vision aids, to help when the eyesight gets highly impaired

How can X-Linked Juvenile Retinoschisis be Prevented?

• Currently, there are no specific methods or guidelines to prevent X-Linked Juvenile Retinoschisis, since it is a genetic condition
• Genetic testing of the expecting parents (and related family members) and prenatal diagnosis (molecular testing of the fetus during pregnancy) may help in understanding the risks better during pregnancy
• If there is a family history of the condition, then genetic counseling will help assess risks, before planning for a child
• Active research is currently being performed to explore the possibilities for treatment and prevention of inherited and acquired genetic disorders, such as X-Linked Juvenile Retinoschisis

Accidental retinal detachment could be prevented by avoiding contact sports and possible head injuries.

What is the Prognosis of X-Linked Juvenile Retinoschisis? (Outcomes/Resolutions)

• The prognosis of X-Linked Juvenile Retinoschisis depends on the severity of the signs and symptoms
• The symptoms of XJR progress at a faster rate during the first 20 years of a patient’s life
• As the individual ages, the disease progression somewhat slows down until age 50, beyond which a steady decline in visual acuity is reported
• Severe visual impairment could occur, which could potentially lead to blindness

Additional and Relevant Useful Information for X-Linked Juvenile Retinoschisis:

It is advised that the patients take ample care so as to not have any head injury, for this might trigger retinal detachment. Refraining from high contact sports is an option to avoid injuries that could potentially result in accidental retinal detachment.