Melanoma is etiologically a very heterogenic malignancy with high aggressiveness and bad prognosis. The incidence of malignant melanoma is increased very probably due to sun abuse. Familial occurrence of malignant melanoma is genetically determined and apart from mutations in genes for CCM1, CCM2, CCM3, CCM4, was repeatedly found in the heterozygotes of mutations for chromosomal instability syndromes with hypersensitivity to ionization. Authors refer the family with familial occurrence of malignant melanoma in middle age in the carrier of 'Slavic' mutation in NBS1 gene on 8q21.

        Key words: familial malignant melanoma, autosomal dominant inheritance, tumour suppressor gene NBS1, Slavic mutation 657del5