甲状腺发育不全的先天性甲状腺功能减退患儿甲状腺激素受体β基因突变研究

Screening of thyroid hormone receptor β mutations in patients with congenital hypothyroidism combined with thyroid dysgenesis

目的：研究山东地区甲状腺发育不全（TD）的先天性甲状腺功能减退（CH）患儿甲状腺激素受体β（TRβ）基因突变类型及特点，为基因诊断及产前诊断提供理论依据。方法通过山东省新生儿筛查系统选取山东省60例 TD 的 CH 病例，提取患儿外周静脉血白细胞全基因组 DNA，用8对序列特异性引物对 TRβ基因的第6-12外显子进行 PCR 扩增，扩增后运用一代测序法（Sanger 测序法）对 PCR 产物直接进行测序。测序结果用 DNA MAN 软件与 TRβ基因的参考序列[美国国立生物技术信息中心（ NCBI）Reference Sequence：NC 000003.12]进行比对，结合比对结果分析是否存在基因突变。结果分析外显子测序结果，在60例患者中并未发现 TRβ基因突变，但在第9外显子和第6外显子区分别发现1个单核苷酸多态性（ SNP）位点（rs3752874，c.735C ﹥ T；rs79220627，c.162G ﹥ A），经分析，这2个 SNP 位点均为同义突变（ Phe→Phe；Ser→Ser），并未引起相应氨基酸发生改变。结论山东地区 TD 的 CH 患者中 TRβ基因突变率低，可能不是该地区TD 的 CH 患者的主要突变类型。

Objective To study the thyroid hormone receptor β（TRβ）gene mutation types and characteristics in children with congenital hypothyroidism（CH）and thyroid dysgenesis（TD）from Shandong Province,and to provide theoretical basis for gene diagnosis and prenatal diagnosis. Methods Sixty cases of TD patients of which genomic DNA were isolated from peripheral blood leukocytes were selected by neonatal screening system in Shandong Province. The exon 6 to 12 of TRβ gene were amplified with 8 pairs of sequence specific primers using PCR and the first generation of sequencing method（Sanger method）to detect mutation. The sequencing results were compared with the TRβ gene reference sequence[National Center for Biotechnology Information（NCBI）Reference Sequence：NC 000003. 12]to see whether there was a mutation. Results Analysis of TRβ in 60 cases of CH patients with TD revealed no mutation was demonstrated in exons 6 - 12,but 2 single nucleotide polymorphism（SNP）（ rs 3752874,c. 735C ﹥ T;rs79220627, c. 162G ﹥ A）were detected. Through the analysis,the 2 SNP were all synonymous mutations（Phe→Phe;Ser→Ser）, without the change of the amino acids. Conclusions TRβ mutation rate is very low,which may not be the main mutation type in CH patients with TD in Shandong Province.