Different genotypes of a functional polymorphism of the TSHR gene are associated with the development and severity of Graves and Hashimotos diseases
Different genotypes of a functional polymorphism of the TSHR gene are associated with the development and severity of Graves and Hashimotos diseases
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TSHR 基因功能多态性的不同基因型与格雷夫斯病和桥本病的发生和严重程度相关
DOI：
10.1111/tan.12190
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
Y
中科院分区：
文献类型：
--
作者：
Inoue;N.;Watanabe;M.;Katsumata;Y.;Hidaka;Y.;Iwatani;Y
自身免疫性甲状腺疾病（AITDs），如桥本病（Hashimoto’s disease， HD）和Graves’s disease (GD)，是非常常见的器官特异性自身免疫性疾病，其严重程度在患者之间存在差异(1)。GD由抗促甲状腺激素受体抗体（TRAb）引起。促甲状腺激素受体（TSHR）由A亚基和B亚基组成，分别由外显子1-9和外显子10编码。A和B亚基之间的分裂导致细胞外A亚基脱落到外周(2)。有研究表明，A亚基的脱落可能导致促甲状腺抗体（TSAb）的产生(3)。ST4是TSHR的一个剪接变体，包含1-9个外显子；然而，没有编码跨膜结构域的外显子10(2)。因此，增加的ST4转录可能会促进shed a亚基的产生。在TSHR基因rs179247多态性中，GD患者AA基因型和A等位基因的频率高于对照组(4)。此外，与GG基因型相比，AA基因型的ST4表达量更高(5)。上述结果表明，AA基因型和A等位基因与GD的发生有关。在这项研究中，我们对这种多态性进行了基因分型，以确定其与GD的严重程度以及HD的发展和严重程度的关系。我们筛选了98例抗甲状腺微粒体抗体（McAb）或抗甲状腺球蛋白抗体（TgAb）阳性的HD患者。在HD患者中，44例患者在50岁之前出现中度至重度甲状腺功能减退，并接受甲状腺素治疗（重度HD）， 33例50岁以上的HD患者未经治疗，表现为甲状腺功能正常（轻度HD）。所有轻度HD患者均表现为可触及的弥漫性甲状腺肿。此外，我们检查了112例诊断时TRAb阳性的GD患者，其中50例GD患者甲状腺功能正常，经甲巯咪唑治疗至少5年，但TRAb仍呈阳性（难治性GD）；停用抗甲状腺药物治疗2年以上仍保持甲状腺功能正常且TRAb阴性的GD患者33例（GD缓解期）。我们还检查了56名甲状腺功能正常且甲状腺自身抗体阴性的健康志愿者（对照组）。所有患者和对照受试者均获得了书面知情同意，研究方案经大阪大学伦理委员会批准。临床特征见表1。采用聚合酶链反应-限制性片段长度多态性（PCRRFLP）方法对rs179247多态性进行基因分型。采用上游（5- catgaagcttttggcttatattattt -3）和下游（5-CTAGTTTCTTGGCTTAAAAAAATA-3）引物扩增TSHR基因。PCR产物用SspI酶切。GD患者AA基因型频率（50.9%）高于对照组（32.1%，P= 0.0201）。HD患者GG基因型频率（23.4%）高于对照组（9.0%，P= 0.0186）。GD患者中A等位基因的频率（70.5%）高于HD患者（55.1%，P= 0.0010；表1）。顽固性GD患者AA基因型和A等位基因的频率（分别为64.0和80.0%）高于缓解性GD患者（分别为30.3和54.6%，P分别为0.0024和0.0005，表1）。重度HD患者GG基因型出现频率（27.3%）高于对照组（9.0%，P= 0.015）。50岁以下发生GD的患者比例…
Autoimmune thyroid diseases (AITDs), such as Hashimoto’s disease (HD) and Graves’ disease (GD), are very frequent organ-specific autoimmune diseases, and the disease severities can vary among patients (1). GD is caused by the anti-thyrotropin receptor antibody (TRAb). The thyrotropin receptor (TSHR) consists of an A and B subunit, which is encoded by exons 1–9 and exon 10, respectively. Cleavage between the A and B subunits results in the shedding of an extracellular A subunit into the periphery (2). It has been suggested that shedding of the A subunit may result in the production of thyroid-stimulating antibody (TSAb)(3). ST4, one of the splicing variants of TSHR, contains 1–9 exons; however, no exon 10, which encodes transmembrane domain (2). Thus, increased ST4 transcription may enhance the generation of a shed A subunit. In the rs179247 polymorphism of the TSHR gene, the frequency of the AA genotype and A allele was higher among GD patients compared with controls (4). In addition, ST4 expression was higher in the AA genotype compared with the GG genotype (5). These results indicated that the AA genotype and A allele were associated with the development of GD. In this study, we genotyped this polymorphism to determine its association with the severity of GD, as well as the development and severity of HD. We screened 98 HD patients who were positive for the anti-thyroid microsomal antibody (McAb) or anti-thyroglobulin antibody (TgAb). Of the HD patients, 44 patients developed moderate to severe hypothyroidism before the age of 50years and were treated with thyroxine (severe HD) and 33 HD patients over the age of 50years were left untreated and demonstrated euthyroid (mild HD). All of the patients with mild HD exhibited a palpable diffuse goiter. In addition, we examined 112 GD patients who were positive for TRAb at the diagnosis, including 50 GD patients who were euthyroid and had been treated with methimazole for at least 5years and were still positive for TRAb (intractable GD); and 33 GD patients who had maintained a euthyroid state and were negative for TRAb for more than 2 years after the discontinuation of the anti-thyroid drug therapy (GD in remission). We also examined 56 healthy volunteers (control subjects) who were euthyroid and negative for thyroid autoantibodies. Written informed consent was obtained from all of the patients and control subjects, and the study protocol was approved by the Ethics Committee of Osaka University. The clinical characteristics are shown in Table 1. The rs179247 polymorphism was genotyped using the polymerase chain reaction-restriction fragment length polymorphism (PCRRFLP) method. The TSHR gene was amplified by PCR using upstream (5-CATGAAGCTTTTGGCTTATATTTT-3) and downstream (5-CTAGTTTCTTGGCTTAAAAAAATA-3) primers. The PCR product was digested by SspI. The frequency of the AA genotype was higher in GD patients (50.9%) compared with control subjects (32.1%, P= 0.0201). In contrast, the frequency of the GG genotype was higher in HD patients (23.4%) compared with control subjects (9.0%, P= 0.0186). The frequency of the A allele was higher in GD patients (70.5%) compared with the HD patients (55.1%, P= 0.0010; Table 1). The frequencies of the AA genotype and A allele were higher in intractable GD patients (64.0 and 80.0%, respectively) compared with GD patients in remission (30.3 and 54.6%; P= 0.0024 and 0.0005, respectively; Table 1). The frequency of the GG genotype was higher in severe HD patients (27.3%) compared with control subjects (9.0%, P= 0.015). The proportion of patients who developed GD under 50 …