HIGH PREVALENCE OF THE POINT MUTATION IN EXON-6 OF THE XERODERMA-PIGMENTOSUM GROUP-A-COMPLEMENTING (XPAC) GENE IN XERODERMA-PIGMENTOSUM GROUP-A PATIENTS IN TUNISIA
C. Nishigori et al., HIGH PREVALENCE OF THE POINT MUTATION IN EXON-6 OF THE XERODERMA-PIGMENTOSUM GROUP-A-COMPLEMENTING (XPAC) GENE IN XERODERMA-PIGMENTOSUM GROUP-A PATIENTS IN TUNISIA, American journal of human genetics, 53(5), 1993, pp. 1001-1006
Xeroderma pigmentosum (XP) patients in Tunisia who belong to the genet
ic complementation group A (XPA) have milder skin symptoms than do Jap
anese XPA patients. Such difference in the clinical features might be
caused by the difference in the site of mutation in the XP A-complemen
ting (XPAC) gene. The purpose of this study is to identify the genetic
alterations in the XPAC gene in the Tunisian XPA patients and to inve
stigate the relationship between the clinical symptoms and the genetic
alterations. Three sites of mutation in the XPAC gene have been ident
ified in the Japanese XPA patients, and about 85% of them have a G-->C
point mutation at the splicing acceptor site of intron 3. We found th
at six (86%) of seven Tunisian XPA patients had a nonsense mutation in
codon 228 in exon 6, because of a CGA-->TGA point mutation, which can
be detected by the HphI RFLP. This type of mutation is the same as th
ose found in two Japanese XPA patients with mild clinical symptoms. Mi
lder skin symptoms in the XPA patients in Tunisia than in those in Jap
an, despite mostly sunny weather and the unsatisfactory sun protection
in Tunisia, should be due to the difference in the mutation site.