CHARACTERIZATION OF MOLECULAR DEFECTS IN XERODERMA-PIGMENTOSUM GROUP-C

Xeroderma pigmentosum (XP) is a rare autosomal recessive disease of hu mans characterized by an accelerated chronic degeneration of sun-expos ed areas of the body, including an elevated risk of developing cancers of the skin. We recently reported the isolation of a gene XPCC that c omplements the repair deficiency of cultured XP-C cells. Here we repor t the results of a characterization of XPCC at the nucleotide level in five XP-C cell lines. Each cell line exhibited a unique mutation that correlated well with the cellular DNA repair deficiency and the clini cal severity of the disease. These results extend our previous observa tions and indicate that defects in XPCC cause Xeroderma pigmentosum gr oup C.