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

本研究的目的是利用日本人群中XPA基因的方正突变在日本人群中存在相对较高的频率，并且使用PCR-RFLP方法可以很容易地发现的事实，通过比较非黑色素瘤皮肤癌患者中XPA基因方正突变的杂合子频率来评估杂合子的癌症风险。我们在682例对照人群中发现5个杂合子，在915例非黑色素瘤皮肤癌患者中发现13个杂合子。两组之间的频率差异无统计学意义。虽然我们之前的研究得到的频率表明，在日本人群中有大约100万个XPA方正突变杂合子，但本研究显示，在非黑色素瘤皮肤癌人群中，XPA方正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.