探讨MS4A2基因rs569108位点多态性与<6岁儿童喘息性疾病易感性、严重程度等临床表型的相关性。

选择2014年1月至2016年12月，于广东省妇幼保健院收治的年龄<6岁的236例儿童喘息性疾病患儿为研究对象，纳入病例组。选择同期于本院进行健康体检的同年龄段的121例健康儿童，纳入对照组。采集2组受试儿口腔上皮细胞样本，并提取DNA，采用实时荧光定量PCR法进行MS4A2基因rs569108位点多态性基因分型检测。2组受试儿的MS4A2基因rs569108位点AA、AG、GG基因型频率分布的Hardy-Weinberg平衡检验，MS4A2基因rs569108位点AA、AG、GG基因型与A、G等位基因频率，以及病例组轻、中、重度儿童喘息性疾病患儿AA、AG、GG基因型频率比较，均采用χ²检验。本研究征得受试儿监护人知情同意，并与之签署临床研究知情同意书。2组受试儿的性别构成比、年龄等一般临床资料比较，差异均无统计学意义(P>0.05)。

①病例组与对照组受试儿MS4A2基因rs569108位点AA、AG、GG基因型频率分布，均符合Hardy-Weinberg平衡定律(P>0.05)。②病例组与对照组受试儿MS4A2基因rs569108位点AA、AG、GG基因型频率及A、G等位基因频率分别比较，差异均无统计意义(P>0.05)。③病例组中，轻、中、重度<6岁儿童喘息性疾病患儿的AA、AG、GG基因型频率分别为75.5%(108/143)、23.8%(34/143)、0.7%(1/143)，67.7%(42/62)、30.1%(18/62)、3.2%(2/62)与58.1%(18/31)、32.2%(10/31)、9.7%(3/31)，其AA、AG、GG基因型频率比较，差异有统计学意义(χ²＝9.186，P＝0.039)；进一步进行两两比较的结果显示，轻、重度<6岁儿童喘息性疾病患儿AA、AG、GG基因型频率比较，差异有统计学意义(χ²＝8.506，P＝0.011)。

MS4A2基因rs569108位点多态性与<6岁儿童喘息性疾病易感性不相关，该位点突变可能不是儿童喘息性疾病的始动因素。但是，MS4A2基因rs569108位点多态性与<6岁儿童喘息性疾病严重程度相关，携带GG纯合子基因型，可能是该病病情加重的危险因素。

To investigate the association between polymorphism of MS4A2 gene rs569108 locus and susceptibility, severity of wheezing illnesses in children under 6 years old.

From January 2014 to December 2016, a total of 236 children under 6 years old with wheezing illnesses in Guangdong Women and Children Hospital were enrolled as case group. And 121 healthy children with the same age who received health examination in the same hospital during the same period were selected as control group. Oral epithelial cell samples were collected from the subjects in two groups, and DNA was abstracted from the buccal mucosa epithelia. Genotypings of MS4A2 gene rs569108 locus polymorphism were performed by real-time-fluorescence quantitation PCR. Genetic Hardy-Weinberg equilibrium, distribution of alleles A and B and genotypes AA, AG and GG of MS4A2 gene rs569108 locus polymorphism between two groups, distribution of genotypes AA, AG and GG of children with different severity degrees of wheezing illnesses in case group were compared by chi-square test. The guardians of all subjects were told and signed the informed consent agreement when their children were included as research subjects. There were no significant differences between two groups in the aspects of gender ratio and age, etc. (P>0.05).

①The distributions of genotypes AA, AG and GG of MS4A2 gene rs569108 locus polymorphism of case group and control group were both in line with Hardy-Weinberg equilibrium (P>0.05), indicating that the samples of both two groups were representative. ②There were no significant differences between two groups in the frequencies of genotypes AA, AG, GG or alleles A and G of MS4A2 gene rs569108 locus polymorphism (P>0.05). ③In case group, the frequencies of genotypes AA, AG, GG of MS4A2 gene rs569108 locus polymorphism in children with mild, moderate, severe wheezing illnesses were 75.5% (108/143), 23.8% (34/143) and 0.7% (1/143), respectively, 67.7% (42/62), 30.1% (18/62) and 3.2% (2/62), respectively, and 58.1% (18/31), 32.2% (10/31) and 9.7% (3/31), respectively. There was significant difference among the three severity degrees of wheezing illnesses in the frequencies of genotypes AA, AG, GG of MS4A2 gene rs569108 locus polymorphism (χ²=9.186, P=0.039). And there was significant difference between the children with mild or severe wheezing illnesses in the frequencies genotypes AA, AG, and GG by multiple comparisons (χ²=8.506, P=0.011).

There is no correlation between polymorphism of MS4A2 gene rs569108 locus and the susceptibility of wheezing illnesses in children under 6 years old. But there is correlation between the severity of wheezing illnesses in children under 6 years old and the polymorphism of MS4A2 gene rs569108 locus. It shows that wheezing children under 6 years old with GG genotype are more susceptible to get more severe degree when wheezing attacks.