Detection of a rare CDKN2A intronic mutation in a Hungarian melanoma-prone family and its role in splicing regulation.

BACKGROUND: The major locus for melanoma predisposition is the cell cycle regulatory CDKN2A gene on chromosome 9p21. However, the frequency of germline coding mutations of the CDKN2A gene is lower than expected in melanoma-prone families linked to chromosome 9p21. OBJECTIVES: To investigate whether the rare IVS1+37 G/C intronic mutation of the CDKN2A gene, recently identified in a Hungarian melanoma-prone family, influences mRNA splicing regulation. METHODS: CDKN2A minigenes containing the wild-type and the mutant intronic sequence were created and transfected into HeLa cells with the aim of studying the mRNA transcripts. RESULTS: The results revealed the emergence of a differential splicing pattern from the wild-type and the mutant minigene, suggesting that this mutation may alter the splicing of CDKN2A primary mRNA and therefore might have a pathogenetic role in familial melanoma. CONCLUSIONS: We believe that these results confirm the importance of the identification and characterization of CDKN2A intronic mutations with a view to improving our understanding of the pathogenesis, and explain why the frequency of germline coding mutations of the CDKN2A gene is lower than expected in melanoma-prone families linked to chromosome 9p21.