Alternative Names
Glioblastoma, retinal; Glioma, retinal; Neuroblastoma, retinal; RB
Symptoms & Characteristics
Retinoblastoma is a rare type of eye cancer that develops in the retina, the part of the eye that detects light and color. Although this disorder can occur at any age, it usually develops in young children.
Most cases of retinoblastoma occur in only one eye, but both eyes can be affected. The most common sign of this disorder is a visible whiteness in the normally black pupil (the opening through which light enters the eye). This unusual whiteness is particularly noticeable in photographs taken with a flash, and is called "cat's eye reflex" or leukocoria. Other signs and symptoms of retinoblastoma include crossed eyes or eyes that do not point in the same direction (strabismus); persistent eye pain, redness, or irritation; and blindness or poor vision in the affected eye.
Some people with retinoblastoma have an hereditary cancer syndrome called inherited retinoblastoma. These people are also at risk to develop a brain tumor called pinealoma. Pinealoma develops in the pineal gland, which is located at the base of the skull. The presence of retinoblastoma and pinealoma together is called trilateral retinoblastoma. Later in life, people with inherited retinoblastoma also have an increased risk of developing bone cancer (osteosarcoma), soft tissue cancers, a form of skin cancer called melanoma, and other types of cancer.
Treatment
Early diagnosis and treatment of retinoblastoma may help save life, eye, and sight.
How Common Is It?
Retinoblastoma affects an estimated 1 in 15,000 to 1 in 20,000 live births. This disease is diagnosed in about 250 children per year in the United States. It accounts for about 3% of all cancers in children younger than 15 years.
Genetics & Inheritance
Retinoblastoma is related to chromosome 13. Variations of the RB1 gene increase the risk of developing retinoblastoma. Mutations in the RB1 gene are responsible for most cases of retinoblastoma.
We have two copies of the RB1 gene – one from each parent. Mutations in the RB1 gene are inherited in an autosomal dominant pattern, which means that one copy of the altered gene in each cell is sufficient to increase cancer risk. A person with retinoblastoma may inherit an altered copy of the gene from one parent, or the altered gene may be the result of a new mutation. For retinoblastoma to develop, a second mutation in the other copy of the RB1 gene must occur in retinal cells during the person's lifetime.
- A person with retinoblastoma is more likely to have inherited retinoblastoma if they have a positive family history or if both their eyes are affected.
A small number of cases of retinoblastoma are caused by a chromosome deletion at 13q14. These affected people may also have mental retardation, growth deficiencies, and characteristic facial features.
Recurrence risk for retinoblastoma within a family depends on different factors. These factors may include if there is a positive family history, if one or both eyes are affected, and the results of genetic testing. A cancer genetic consultation with a trained genetic professional is important for a complete evaluation, accurate diagnosis, as well as discussion of the benefits and limitations of testing and recurrence risk.
Genetic Testing
Cancer predisposition testing for retinoblastoma may be available through an in person genetic consultation for people who are considered at risk. Use our find a genetic professional directory to locate a trained genetic professional in your area.
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