Evaluation of the skin cancer risk among heterozygotes bearing a founder mutation allele unique to a Japanese population at xeroderma pigmentosum group A (XPA) gene

本研究的目的是通过比较非黑色素瘤皮肤癌患者和对照人群中携带XPA基因方正突变的杂合子的频率，来评估杂合子的致癌风险。利用XPA基因方正突变在日本人群中存在的相对较高的频率，并利用PCR-RFLP方法，我们在682名对照人群中发现了5个杂合子，在915个非黑色素瘤皮肤癌中发现了13个杂合子。两组的频率在统计学上没有显著差异。虽然我们先前的研究表明，日本人群中约有100万个XPA创始人突变杂合子，但这项研究发现，在非黑色素瘤皮肤癌中，XPA创始人突变杂合子的频率并不高于对照人群。

The aim of this study is to evaluate the cancer risk of heterozygotes by comparing the frequency of heterozygotes bearing a founder mutation in the XPA gene in nonmelanoma skin cancer patients to control population, by taking advantage of the fact that a founder mutation at the XPA gene exists at a relatively high frequency among the Japanese population and can be found easily using the PCR-RFLP method.We found 5 heterozygotes among 682 individuals in a control population and 13 heterozygotes among 915 nonmelanoma skin cancers. There was no statistically-significant difference between the frequencies of both groups. Although the frequency obtained from our previous study implies that there are about 1 million heterozygotes of the XPA founder mutation in the Japanese population, this study revealed that the frequency of heterozygotes of XPA founder mutation was not higher among nonmelanoma skin cancers than that in the control population.