高通量基因捕获测序技术在12个耳聋家庭中的应用

A next-generation sequencing gene panel for molecular diagnosis in twelve Chinese families with non-syndromic sensorineural hearing loss

目的分析12个耳聋家庭的临床特征,进行候选致病基因的突变检测。方法对12个耳聋家庭的患者进行病史采集、全身检查、听力学评估及颞骨CT检查;抽提家庭成员外周血基因组DNA;整理分析家系资料绘制系谱图;使用定向捕获联合二代测序技术进行耳聋基因检测;对可疑基因进行Sanger测序验证。结果 12个耳聋家庭的13名耳聋患者表现为双侧不同程度的感音神经性耳聋。家庭1-7耳聋患者明确GJB2双等位基因突变致聋,分别是:c.235del C/c.235del C,c.235del C/c.176del16,c.235del C/c.299del AT,c.235del C/c.511_512ins AACG/c.235del C/c.605ins46,c.235del C/c.109G>A,c.109G>A/c.109G>A;家庭8-9先证者均为SLC26A4复合杂合突变致聋,分别是:c.589G>A/c.1975G>C,c.919-2A>G/c.-2071_307+3801del7666;其中,家庭10-12先证者,经过数据分析后分别得到8、5和3个可疑突变位点,在相应的家系中不与耳聋表型共分离,故未发现其致病基因。结论本研究明确了9个非综合征耳聋家庭的致病突变,同时证实高通量基因捕获测序技术是一种高效的耳聋基因检测工具。

Objective To investigate the clinical characteristics and genetic etiology of non-syndromic deafness in twelve Chinese families. Methods Detailed medical and audiological examinations,as well as a computed tomography scan of the temporal bone,were performed. Genomic DNA was also extracted from the peripheral blood samples obtained from the family members. Targeted next-generation sequencing（ NGS） for deafness-related genes was used to identify the mutation in the probands in the 12 families. The results were confirmed using Sanger sequencing. Results All probands exhibited different degrees of non-syndromic sensorineural hearing loss. GJB2 mutations were identified in seven families. The mutations included c. 235 del C/c. 235 del C, c. 235 del C/c. 176del16, c. 235 del C/c. 299 del AT,c.235 del C/c.511_512ins AACG,c.235 del C/c. 605ins46,c. 235 del C/c. 109 G A,and c. 109 G A/c. 109 G A. Bi-allelic mutations of SLC26A4 were identified in 2 families. The mutations included c. 589 G A/c. 1975 G C; c. 919-2A G/c.-2071_307＋3801del7666. Co-segregation of mutations and deafness was confirmed within each family using Sanger sequencing. No pathogenic mutations within known deafness genes were identified in families 10,11, and 12.Conclusion Different combinations of mutations of GJB2 and/or SLC26A4 lead to different hearing impairment phenotypes. This study also confirmed that the targeted NGS technique is an efficient genetic test.