[Polygenic inheritance of familial malignant melanoma].

Familial occurrence of malignant melanoma is mostly due to a hereditary disposition which is phenotypically characterized by light complexion and multiple precursor nevi. The inheritance of this disposition is not monogenic but polygenic. The following arguments are in favor of polygenic inheritance: Lack of a uniform pattern of transmission, frequent sporadic occurrence of this phenotype, variable intensity of manifestation within the same family, evidence for polygenic inheritance of fair complexion, and demonstration of polygenic inheritance of melanoma in Xiphophorin fish. In melanoma families, children of affected women develop melanoma more frequently than children of affected men. The authors interpret this phenomenon as a manifestation of the Carter effect. This mechanism is proposed as a new argument in favor of a polygenic inheritance of familial malignant melanoma.