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

Content: these changes may help explain variations in the development and growth of retinoblastoma and other types of tumors in different people. A small percentage of retinoblastomas are caused by deletions in the region of chromosome 13 that contains the RB1 gene. Because these chromosomal changes involve several genes in addition to RB1, affected children usually also have intellectual disability, slow growth, and distinctive facial features (such as prominent eyebrows, a short nose with a broad nasal bridge, and ear abnormalities). Learn more about the genes and chromosome associated with Retinoblastoma
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MYCN
RB1
chromosome 13
Inheritance
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Researchers estimate that one-third of all retinoblastomas are hereditary, which means that RB1 gene mutations are present in all of the body's cells, including reproductive cells (sperm or eggs). People with hereditary retinoblastoma may have a family history of the disease, and they are at risk of passing on the mutated RB1 gene to the next generation. 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.