Genetics

Approximately 1 in 75 people in North America will develop melanoma, and the presence of 1 or more of the following increases the risk 10-fold: atypical moles, more than 100 typical moles, or a family history of 2 first-degree relatives with melanoma. Five percent to 12% of melanomas occur in individuals with a familial predisposition, but not all are part of a hereditary melanoma syndrome. Two genes, cyclin-dependent kinase (CDK) inhibitor 2A and CDK4, account for up to half the cases of hereditary melanoma. Mutations in these genes are associated with a substantial lifetime risk of melanoma.

Bottom line. High-risk families can be offered referral for genetic counseling. Although genetic testing is available, there is a lack of consensus on how results should alter clinical recommendations. Melanoma prevention and surveillance recommendations should be based on the patient’s personal and family history.

The complete Gene Messenger—Familial Melanoma by the GenetiKit research team is available on CFPlus.* Past Gene Messenger articles can be accessed on-line at www.cfp.ca. On the home page, click on Collections in the left-hand menu, then click on Genetics.

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