分子诊断在性别发育异常诊断中的应用

目的 性发育异常是一组多基因介导的遗传性疾病,其遗传学病因异常复杂,但临床表型的多样化,导致临床实践中诊断比较困难.近年来,基因测序技术广泛应用于多种先天性疾病的诊断领域,本研究利用基因测序和基因芯片技术对临床诊断为性发育异常患儿进行基因检测,初步探讨性发育异常的分子病因,探索分子诊断技术用于性发育异常诊断的可能性.方法 22例患儿临床诊断为性发育异常,取全血2 ml并获取DNA.其中5例采用基因芯片技术检测已知的性发育异常相关基因,另17例采用全外显子测序技术检测可能的基因变化.检测结果再采用一代的Sanger测序进行验证.对于阳性发现患儿,取其父、母全血各2 ml,采用Sanger测序探究基因变化来源.结果 5例基因芯片检测患儿中,1例卵睾型性发育异常存在17号染色体中SOX9基因重复(Chr17:70,117,161-70,122,560).其余行全外显子测序17例患儿中5例发现阳性基因变化.这5例致病性基因变化分别为:1例肾上腺发育不良存在DAX1基因错义突变(c.871T＞G,p.W291G),1例肾上腺皮质增生为CYP21A2基因中2个致病性无义突变(c.292+ 1G＞A,c.293-13 A/C＞G),1例Charge综合征为CDH7基因移码突变(c.2916_2917delGT;p.Gln972HisfsX22),2例雄激素不敏感综合征患儿分别存在AR基因错义突变(c.2612C＞T;p.Ala871Val) AR基因错义突变(c.528C＞A;p.Ser176Arg).结论 二代测序技术及基因芯片发现可导致性发育异常的基因突变,可帮助明确病因,提高了诊断精准度.分子诊断技术在性发育异常诊断中的作用已初步显现.

Molecular diagnostics of disorders of sex development

Objective To elucidate the molecular pathogenesis of DSD and exploring the possibility of its molecular diagnostics.Methods Genomic DNA was extracted from peripheral blood samples from 22 DSD patients.Five samples were detected by CMA while genomic DNA of other samples was analyzed by whole exome sequencing.And positive variants and parental blood samples were verified by Sanger sequencing.Results Among 6 novel mutations,1 duplication upstream of SOX9 in chromosome 17(Chr17:70,117,161-70,122,560) with ovotesticular DSD was identified by CMA and 5 genetic mutations by whole exome sequencing and verified by Sanger sequencing.There were 5 each of missense mutation (c.871T＞G,p.W291G)in DAX1 with congenital adrenal hypoplasia,nonsense mutation(c.292 + 1G＞A,c.293-13A/C＞G)in CYP21 A2 with congenital adrenal hyperplasia,frameshift mutation(c.2916_2917delGT;p.Gln972 HisfsX22)in CDH7 with CHARGE syndrome,missense mutation (c.2612C＞T;p.Ala871Val) and missense mutation (c.528C＞A;p.Ser176 Arg) in AR with androgen insensitivity syndrome.Conclusions Genetic diagnosis via CMA and whole exome sequencing is feasible for DSD patients.Thus it provides rationales for clinical diagnosis of other diseases.