目的　探讨甲状腺球蛋白（TG）低下的先天性甲状腺功能减退症（CH）家系TG基因突变特点，并分析基因型 与临床表型的关系。方法　回顾1个姐弟2人同患TG低下的 CH 家系，从外周血中提取基因组 DNA，进行TG基因突变检 测。结果　患儿父亲TG基因发生c.274+2T>G杂合变异，母亲为c.2512C>T杂合变异。患儿姐弟二人TG基因均发现上 述2个变异，为复合杂合变异，c.2512C>T为新发现的突变位点，致病性尚未见文献报道。结论　TG基因突变引起蛋白质 功能改变导致CH。该研究发现1个新的TG基因突变位点。

Objective　To explore the characteristics of TG gene mutation in a family with congenital hypothyroidism (CH) and low thyroglobulin (TG) and further to analyze the relationship between genotype and clinical phenotype. Method　The genomic DNA was extracted for TG gene detection from peripheral blood of two siblings in a CH family with low TG. Results Two heterozygous variations, c.274+2T>G and c.2512C>T, were found in TG gene of their father and mother, respectively. Both of the two mutations above were found in the TG gene of two siblings and are compound heterozygous mutations. The c.2512C>T was a newly discovered mutation site, and the pathogenicity has not been reported in the literature. Conclusion　Mutations in the TG gene cause changes in protein function leading to CH. The study found a new TG gene mutation site.