Title: Retinoblastoma: MedlinePlus Genetics
Headings: Retinoblastoma
Retinoblastoma
Description
Frequency
Causes
Inheritance
Other Names for This Condition
Additional Information & Resources
References

Content: The other two-thirds of retinoblastomas are non-hereditary, which means that RB1 gene mutations are present only in cells of the eye and cannot be passed to the next generation. In hereditary retinoblastoma, mutations in the RB1 gene 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 fertilization. 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 certain retinal cells acquire mutations. People with non-hereditary retinoblastoma are not at risk of passing these RB1 gene mutations to their children.