The inheritance pattern of familial retinoblastoma is
Ref Robbins 7/e p1442,299- 300,9/e p292-293 In hereditary retinoblastoma, mutations in the RB1gene appear to be inherited in an autosomal dominant pattern. Autosomal dominant inheritance means that one copy of the altered gene in each cell is sufficient to increase the risk of cancer. A person with hereditary retinoblastoma may inherit an altered copy of the RB1 gene from one parent, or the altered gene may be the result of a new mutation that occurs in an egg or sperm cell or just after feilization. For retinoblastoma to develop, a mutation involving the other copy of the RB1 gene must occur in retinal cells during the person's lifetime. This second mutation usually occurs in childhood, typically leading to the development of retinoblastoma in both eyes. In the non-hereditary form of retinoblastoma, typically only one eye is affected and there is no family history of the disease. Affected individuals are born with two normal copies of the RB1 gene. Then, usually in early childhood, both copies of the RB1 gene in ceain retinal cells acquire mutations. People with non-hereditary retinoblastoma are not at risk of passing these RB1 gene mutations to their children. However, without genetic testing it can be difficult to tell whether a person with retinoblastoma in one eye has the hereditary or the non-hereditary form of the disease.
Autosomal recessive
Autosomal dominant
X linked dominant
X linked recessive
General anatomy