A rare inherited form of cutaneous melanoma with characteristics of development of histologically confirmed melanoma in two first degrees relatives or more relatives in an affected family. It is thought to account for about 10% of all cases of cutaneous melanoma. Tends to occur earlier than non-familial melanoma. The risk of familial melanoma is closely related to a wide range of genetic alterations in susceptibility genes but also appears to be influenced by phenotypic risk factors, such as pigmentation, freckling and sun reactions. Complex interactions between genetic and environmental factors are therefore thought to underlie the disease. The most common high-penetrance susceptibility gene implicated is CDKN2A, accounting for predisposition in approximately 20% of cases. In some affected families, susceptibility is consistent with autosomal dominant inheritance but in most cases, a polygenic mode of inheritance appears likely.