小阴茎儿童类固醇生成因子-1基因异常研究

Research about SF1 gene abnormality in children with micropenis

目的探寻45例小阴茎儿童类固醇生成因子-1(steroidogenic factor-1,SF1)的基因异常情况,进一步了解突变对阴茎分化、发育及性腺功能的影响。方法收集2011年10月至2013年2月就诊于上海市儿童医院内分泌科的小阴茎患儿并选取50名健康儿童做对照。抽取其外周血标本提取DNA,PCR扩增产物并进行SF1基因测序分析。测序结果用比对软件Sequencher进行序列比对。结果在45例患儿中检测到14例突变,共4种;其中10例突变为c.437G>C(p.G146A),经Pubmed的单核苷酸多态性(SNP)库证实为多态性,其rs编号rs1110061,对该SNP位点进行Hardy-Weinberg群体遗传平衡检验,结果P值均>0.05,符合群体遗传平衡,组间各基因型(GG、GC、CC)及等位基因(G/C)的频率在2组间的分布差异均无统计学意义。余4例突变集中在外显子4和6,包括2种未报道的错义突变及1种同义突变。2种错义突变分别是2例c.565C>T(p.P189S)突变,1例c.1056G>T(p.Q352H)突变;1例同义突变是1062(G>A)。运用Polyhen及Mutaion-tastor软件预测1056(G>T)造成的Q352H氨基酸改变引起疾病,而c.565C>T(p.P189S)突变预测对蛋白功能无明显影响。结论 SF1基因异常是单纯性小阴茎患儿的少见病因,仅1例c.1056G>T(p.Q352H)突变可能是单纯性小阴茎患儿致病突变之一,该突变对下丘脑-垂体及睾丸性激素分泌功能无影响,对以后生育功能的影响有待随访;SF1的rs1110061多态性位点与小阴茎的发生无明显相关性,需扩大样本量进一步研究。

Objective To explore steroidogenic factor 1 （steroidogenie factor 1, SF1） genetic abnormalities in 45 cases of micropenis children, and to understand the influence of mutation on the penis differentiation, development and sex gland function. Methods From October 2011 to February 2013 in endocrinology department of the Shanghai Children＇s hospital the children with micropenis were collected and 50 healthy children as control, and the peripheral blood was taken and DNA extracted, then PCR amplification products and SF1 gene sequencing analysis were made. Sequenc- ing results were compared using sequeneher software for sequence alignment. Results In 45 cases detected there were 14 cases of mutation, a total of 4 kinds, including 10 cases of mutation for c. 437 G〉 C （p.G146A） , confirmed by Pubmed SNP library as polymorphism; the rs code was rsl 110061, and the Hardy-Weinberg population genetic balance test was done on the SNP loci, the result for P values 〉 0.05, which was in line with the population genetic equilibrium ; the distribution of each genotype between the groups （CG, GC, CC） and the frequency of allele （C/C） between the two groups had no significant statistical difference. The rest 4 cases of mutation focused on Exons 4 and 6, including two kinds of missense mutation not being reported and one kind of synonymous mutation. Two missense mutations were respectively two cases of c. 565 C 〉 T （p.P189S） mutation and one case of c. 1056 G 〉 T （p.Q352H） mutation; one case of synonymous mutations was 1062 （G 〉 A）. Polyhen and Mutaion-tastor software to predict 1056 （G 〉 T） caused disease by Q352H amino acid change, however, c.565C 〉 T （p.P189S） mutations prediction had no obvious effect on protein function. Conclusion SF1 genetic abnormality is an uncommon cause in children with micropenis, only one sample c.1056 G〉 T （p.Q352H） may be one of the pathogenic mutations in children with micropenis. This mutation currently has no effect on the hypothalamus-pituitary and testicular hormone secretion, and the impact on future reproductive function needs to be followed explicitly. The correlation between SF1 rsl 110061 polymorphism and micropenis needs a further study.