Retinoblastoma causes
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Simrat Sarai, M.D. [2]
Overview
Retinoblastoma is caused by
Causes
Retinoblastoma is caused by the abnormal overgrowth of retinal cells. This tumor mostly arises from a mutational change on long arm of chromosome 13. However, it may also occur due to Heritable retinoblastoma
- In children with the heritable genetic form of retinoblastoma there is a mutation on chromosome 13, called the RB1 gene.[1] The defective RB1 gene can be inherited from either parent; in some children, however, the mutation occurs in the early stages of fetal development. Inheritance is autosomal dominant with 90% penetrance.[2]
- The development of retinoblastoma can be explained by the two-hit model. According to the two-hit model, two events are necessary for the retinal cell or cells to develop into tumors. The first mutational event can be inherited (germline or constitutional) and would then be present in all cells in the body. The second “hit” results in the loss of the remaining normal allele (gene) and occurs within a particular retinal cell. In the sporadic, nonheritable form of retinoblastoma, both mutational events occur within a single retinal cell after fertilization (somatic events), resulting in unilateral retinoblastoma.
- Somatic amplification of the MYCN oncogene is responsible for some cases of non-hereditary, early-onset, aggressive, unilateral retinoblastoma.
Sporadic heritable retinoblastoma
- The exact cause of the sporadic heritable form of the disease is still unclear.
- Since the sporadic form of retinoblastoma occurs due to a new germline mutation, it should occur before the conception. For this reason, preconception exposure to mutagens is hypothesized to be the potential risk factors.[3]
- 13q deletion syndrome may also cause retinoblastoma. However, the tumor tends to occur at a later age and unilaterally.[4]
- For more information click here.
References
- ↑ Du, W; Pogoriler, J (2006). "Retinoblastoma family genes". Oncogene. 25 (38): 5190–5200. doi:10.1038/sj.onc.1209651. ISSN 0950-9232.
- ↑ Retinoblastoma. Wikipedia(2015) https://en.wikipedia.org/wiki/Retinoblastoma Accessed on October 10, 2015
- ↑ Singh, Arun (2007). Clinical ophthalmic oncology. Edinburgh: Elsevier Saunders. ISBN 978-1-4160-3167-3.
- ↑ Clark, Robin D.; Avishay, Stefanie G. (2015). "Retinoblastoma: Genetic Counseling and Testing": 77–88. doi:10.1007/978-3-662-43451-2_8.