What is retinoblastoma?
Retinoblastoma (RB) is a type of eye tumor that develops during childhood. This tumor develops in the retina, which is a part of the eye that helps us detect light and color. RB may occur in one or both eyes.
The first sign of RB may be when parents notice a white light reflex (leukocoria) of the pupil that occurs when light is shone into a child's eye at a certain angle, especially when taking a photo using a flash. Children may also appear to be cross eyed (strabismus), have redness or swelling of the eye, or have poor or worsened vision.
RB can be non-hereditary or hereditary, but both forms occur when both copies of the RB1 gene are affected by a gene change (mutation). Sixty percent of children affected with RB have a non-hereditary or sporadic form. The sporadic form of RB most often develops when one cell in one eye develops two disease causing variants or mutations in the RB1 gene. It is not associated with an underlying RB1 gene change in every cell of the body or an increased risk for developing other tumors later in life.
The hereditary (or congenital) form of RB is related to an underlying genetic change (or mutation) in the RB1 gene which is found in every cell of the body and then the occurrence of a second disease causing gene change in the RB1 gene early in life. Hereditary retinoblastoma is often associated with tumors in both eyes (bilateral retinoblastoma) and also with increased risk of other cancers in adulthood.
Having a single underlying genetic change (or mutation) in the RB1 gene which is found in every cell of the body runs through families in an autosomal dominant pattern. This means that a person with hereditary retinoblastoma has a 50% chance of having a child with a RB1 mutation. Most people who inherit a RB1 mutation in all cells of their body will develop a second disease causing variant in RB1 that results in retinoblastoma, but not all.
Whether hereditary or not, if RB tumors are not treated, they can travel outside of the eye to affect other organs. Overall, with treatment, more than 90% of individuals with RB go into remission. The chances of long-term survival for a child with RB are better if the tumor is treated before it spreads to other parts of the body.
SOURCE: Emory University - Department of Human Genetics in collaboration with ThinkGenetic • https://www.thinkgenetic.com/diseases/retinoblastoma-109952/overview/67962 • DATE UPDATED: 2019-11-28
Retinoblastoma - Genetics Home Reference - NIH. (n.d.). Retrieved February 23, 2019, from https://ghr.nlm.nih.gov/condition/retinoblastoma# Accessed 27NOV19.
American Cancer Association. Retinoblastoma. https://www.cancer.org/cancer/retinoblastoma/ Accessed 27NOV19.
Childrens National. Pediatric Retinoblastoma. https://childrensnational.org/visit/conditions-and-treatments/cancer/retinoblastoma Accessed 27NOV19.