Supplementary Material for: Association of the –1072G/A Polymorphism in the <b><i>LTC4S</i></b> Gene with Asthma in an Indian Population

<b><i>Background:</i></b> Atopic asthma, the most common chronic disease affecting children and young adults, is a complex disorder with variable phenotypes. Cysteine leukotrienes (Cys-LTs) are powerful bronchoconstrictors and play a critical role in airway inflammation and remodeling that are characteristic of asthma. <b><i>Objective:</i></b> To investigate the association of <i>ALOX5</i>, <i>LTC4S </i>and<i> CysLTR2 </i>gene polymorphisms with atopic asthma in an Indian population. <b><i>Methods:</i></b> A total of 19 single nucleotide polymorphisms (SNPs) within these genes were genotyped in a family-based cohort (n = 239) and a case-control cohort (139 cases and 194 controls) followed by association analyses. <b><i>Results:</i></b> We found a significant association of the –1072G/A (rs3776944) SNP with atopic asthma in the family-based association analysis (p = 0.0004). These results were also replicated in the case-control cohort (p = 0.009). The allele A was negatively associated with atopic asthma. We also noted a significant association in the two-locus (rs3776944G/A and rs730012A/C) haplotypic analysis of this gene both in the family-based (p = 0.03) and the case-control (p = 0.02) analyses. <b><i>Conclusion:</i></b> This study supports the role of the <i>LTC4S </i>gene polymorphism in genetic susceptibility to atopic asthma in an Indian population.**背景：** 特应性哮喘（atopic asthma）是累及儿童与青年群体的最常见慢性病，属于表型多样的复杂疾病。半胱氨酰白三烯（cysteine leukotrienes, Cys-LTs）是强效支气管收缩物质，在哮喘特征性的气道炎症与气道重塑过程中发挥关键作用。**目的：** 本研究旨在探究ALOX5、LTC4S及CysLTR2基因多态性与印度人群特应性哮喘的关联。**方法：** 本研究在基于家系的队列（n=239）与病例对照队列（包含139例病例及194名对照）中，对上述基因内的共计19个单核苷酸多态性（single nucleotide polymorphisms, SNPs）进行基因分型，随后开展关联分析。**结果：** 在基于家系的关联分析中，本研究发现–1072G/A（rs3776944）位点的单核苷酸多态性与特应性哮喘存在显著关联（p=0.0004），该结果在病例对照队列中得到了重复验证（p=0.009）。等位基因A与特应性哮喘呈负相关。此外，针对该基因开展的两位点（rs3776944G/A与rs730012A/C）单体型分析中，无论是基于家系的分析（p=0.03）还是病例对照分析（p=0.02），均观察到显著关联。**结论：** 本研究证实，LTC4S基因多态性与印度人群特应性哮喘的遗传易感性相关。