甲状腺功能亢进症儿童促甲状腺素受体基因突变分析

Analysis of thyroid stimulating hormone receptor gene mutation in children with hyperthyroidism

目的探讨中国广州地区甲状腺功能亢进症(甲亢)患儿促甲状腺素受体(thyroid stimulating hormone receptor, TSHR)基因突变特点。方法2009年7月~2014年7月在我院诊断为甲亢的患儿90例,男28例,女62例,诊断年龄(7.5±3.4)岁。提取患儿的外周血基因组DNA,采用聚合酶链式反应(PCR)扩增目的片段并直接测序,对患儿的TSHR基因第10外显子进行突变检测分析,50例健康儿童作为正常对照。探讨TSHR基因与儿童甲亢的相关性。结果在90例甲亢患儿中,检测到3种突变,1种同义突变(c.1842A>G,p.V614V),2个错义突变(c.2119C>T,p.R707W、c.2181G>C,p.D727E)。p.V614V没有改变氨基酸,不影响TSHR的结构和功能,无致病性。p.R707W是与人类癌症发病相关的SNP位点。甲亢组D727E中C等位基因的发生频率为86.7%,正常对照组为55%,两组间D727E等位基因出现的频率有显著差异(P<0.01)。进一步的logistic回归分析发现,D727E与儿童甲亢可能具有一定的相关性(OR=18.86,P<0.01)。结论本研究对中国广州地区90例甲亢患儿TSHR基因的第10外显子分析,发现3个突变位点(c.1842A>G和p.V614V、c.2119C>T和p.R707W、c.2181G>C和p.D727E),p.V614V和p.R707W与甲亢无关,p.D727E与儿童甲亢可能具有一定的相关性。

Objective To explore the characterization of thyroid stimulating hormone receptor(TSHR) gene mutational spectrum in children with hyperthyroidism from Guangzhou. Methods Ninety children were diagnosed with hyperthyroidism from July 2009 to July 2014 in our institute. Their median age at diagnosis was(7.5±3.4) years, and there were 28 males and 62 females. Mutational analysis were performed by performing polymerase chain reaction(PCR) and DNA direct sequencing of exon 10 of TSHR gene. TSHR gene mutations from 50 unrelated healthy children were served as controls. The correlation between TSHR gene and hyperthyroidism in children was explored. Results A total of 3 mutations were identified in ninety children who were diagnosed with hyperthyroidism, one synonymous mutations(p.V614V), and two missense mutations(p.R707W and p. D727E). Mutation of p. V614V do not change amino acid and do not influence the structure and function of TSHR, no pathogenicity. p. R707W is a SNP associated with human cancers. The frequency of C allele of the D727E in children with hyperthyroidism was 86.7%, while 55.0% in the controls, significant different between the children with hyperthyroidism and the controls(P<0.01). In this study, a very high association between the D727E SNP and hyperthyroidism(OR=18.86, P<0.01) was found. Conclusion Three different mutations of TSHR gene exon 10 were identified in 90 children with hyperthyroidism,(c.1842A>G, p.V614V、c.2119C>T, p.R707W、c.2181G>C, p.D727E), there were association between p. D727E and hyperthyroidism, nor p. V614V and p. R707W. Finally, p. D727E may be correlated with hyperthyroidism in children.