中国人哮喘易感性与染色体5q31～33区连锁关系的初步研究

目的获得中国人相关位点的资料，确定中国人哮喘易感性与染色体５ｑ３１～３３区域的连锁关系。方法采集３２个哮喘家系共１９２份样品，并取３９个正常无关个体为对照；用同位素掺入的聚合酶链反应（ＰＣＲ）法扩增多态性遗传标记Ｄ５Ｓ４３６和Ｄ５Ｓ３９３，通过受累同胞配对法进行Ｄ５Ｓ４３６和Ｄ５Ｓ３９３与哮喘和高血清总ＩｇＥ的连锁分析。结果正常对照分析：Ｄ５Ｓ４３６共获得９个等位片段，多态性信息含量（ＰＩＣ）为０．８０３，杂合度（ＨＥＴ）为０．８２３，Ｄ５Ｓ３９３共有１１个等位片段，ＰＩＣ为０．８９２，ＨＥＴ为０．８９８，表明两个位点均属于高度多态性的遗传标记。连锁分析：Ｄ５Ｓ４３６与哮喘呈连锁状态（Ｐ＜０．０５），Ｄ５Ｓ３９３与哮喘没有连锁关系；Ｄ５Ｓ４３６和Ｄ５Ｓ３９３与高血清总ＩｇＥ都没有显示连锁关系。结论染色体５ｑ３１～３３区可能存在与中国人哮喘易感基因相关的１个或多个位点，是进行中国人哮喘易感基因研究的重要候选区域之一。

A preliminary study on linkage between genetic susceptibility to asthma and chromosome 5q31 33 region in Chinese population

Objective To accumulate data on the asthma related loci in Chinese population and determine whether genetic susceptibility to asthma was linked to the chromosome 5q31 33 region. Methods One hundred ninety two samples from 32 families from Zhaoan county in Fujian province were collected. Specimens from 39 unrelated individuals were collected and used as normal controls. The polymorphic markers D5S436 and D5S393 were amplified by PCR incorporated with radioactive isotope. Linkage analysis was performed using the sib pair method. Results Nine alleles in D5S436 were obtained. The polymorphism information content (PIC) and heterozygosity of D5S436 was 0.803 and 0.823 respectively. There were 11 alleles in D5S393. The PIC and heterozygosity was 0.892 and 0.898, respectively. These data indicated that both were highly polymorphic markers and can be convincingly used in positional cloning. Significant evidence for linkage to asthma was observed with D5S436 ( P <0.05) but not with D5S393. No significant linkage of total serum IgE to D5S 436 or to D5S 393 could be identified. Conclusion The preliminary results suggested that the region of chromosome 5q31 33 may contain one or more loci associated with the susceptibility to asthma in Chinese population. Therefore, it may still be a very attractive candidate region for further approach.