Familial Malignant Melanoma
Familial malignant melanoma is a term usually referring to families in which 2 or more first-degree relatives, such as a parent, sibling, and/or child, have a type of skin cancer called melanoma.
Overall, about 8% of people newly diagnosed with melanoma have a first-degree relative with melanoma. A much smaller percentage, about 1% to 2%, has 2 or more close relatives with melanoma.
These families may have inherited genes which have made them especially susceptible to developing melanoma.
The risk of familial melanoma is due to an effect of genetic alterations in susceptibility genes as well as risk factors such exposure to UV radiation and pigmentation.
The most common gene implicated is CDKN2A. CDK4, another high risk gene, is rarely involved. Mutations of BAP1,POT1 or MITF have recently been reported and may explain some melanoma familial agregations.
Familial malignant melanoma due to a mutation in a gene such CDKN2A, is an autosomal dominant syndrome: one mutated copy of the gene is sufficient for a person to have melanoma susceptibility. A person with an autosomal dominant syndrome has a 50 percent chance of having an affected child with one mutated gene.
Individuals at high risk should be educated on the importance of melanoma prevention, early detection and should undergo periodically dermatologic examination by a specialist. Families with familial malignant melanoma due to a mutation in CDKN2A, may have an increased risk of pancreatic càncer (up to 17% increased risk). Therefore, in these famílies ultrasonography and/or MRI should be considered.
Development of this guideline will start in September 2023