内蒙古赤峰市聋校聋儿SLC26A4基因分析

目的 利用基因诊断的方法调查内蒙古赤峰市特教学校耳聋患者的常见分子病因,本文着重进行SLC26A4基因全序列突变分析.方法 调查对象来自赤峰市特教学校耳聋患者134例,对照组为中国北方听力正常者100例.所有受检患者均采集外周血并提取DNA,进行SLC26A4基因编码区20个外显子测序,对携带SLC26A4基因突变的患者行高分辨率颞骨CT检查,发现内耳影像学异常的患者进一步行甲状腺功能及甲状腺B超检查.结果 134例耳聋患者中32例携带SLC26A4基因突变,对其中29例进行颞骨CT检查发现20例内耳影像学异常(前庭水管扩大18例,前庭水管扩大合并其他内耳畸形1例,单纯Mondini畸形1例);进一步甲状腺B超和甲状腺功能检查发现1例前庭水管扩大的耳聋患者甲状腺右叶囊性占位,但甲状腺功能正常.其余19例患者甲状腺B超和甲状腺功能检查结果均正常或处于临界值.发现SLC26A4基因12种新的变异.结论 通过对赤峰市特教学校耳聋患者进行SLC26A4基因全序列筛查结合内耳影像学检查,诊断前庭水管扩大和/或内耳畸形20例,为该校14.93%(20/134)耳聋学生明确了病因;在该地区SLC26A4基因是仅次于GJB2基因(16.42%,22/134)的导致遗传性耳聋的常见病因.

Genotypic and phenotypic analysis of SLC26A4 gene in deaf patients of Chifeng area by whole gene sequencing strategy

OBJECTIVE To investigate the genetic causes of deaf patients in a special educational school of Chifeng city, Inner Mongolia by SLC26A4 whole gene sequencing. This study focused on analyzing mutations of coding sequence of SLC26A4 gene and their relevant phenotype. METHODS DNA were extracted from peripheral blood of 134 deaf patients of Chifeng special educational school and 100 normal hearing controls in Northern China. SLC26A4 gene mutation was analyzed by direct sequencing for its 20 coding exons. All individuals found with SLC26A4 mutation were given temporal bone CT scan, and those with confirmed enlarged vestibular aqueduct and/or other malformation of inner ear were then given further ultrasound scan of thyroid and thyroid hormone assays. RESULTS The sequencing results revealed 32 cases carried SLC26A4 mutation. Twenty-nine cases underwent temporal bone CT scan. Twentycases were confirmed to have malformation of inner ear by CT scan (eighteen were EVA, one was EVA and other inner ear malformation and one was Mondini Syndrome). The shape and function of thyroid were confirmed to be normal by ultrasound scan of thyroid and thyroid hormone assays in nineteen of these 20 patients except one who had cystoid change in the right side of thyroid. Twelve types of novel variants of SLC26A4 gene were found. CONCLUSION Byscreening SLC26A4 gene coupled with temporal bone CT scan ,we could determine genetic cause related to this gene up to 14.93 % of deaf patients in special educational school of Chifeng city. SLC26A4 is another common gene besides GJB2 that cause deafness in this area. The discovery of novel variants of SLC26A4 gene makes the mutational and polymorphic spectrum more plentiful in Chinese population.