Objective: To investigate the clinical and genetic characteristics of nonsyndromic sensorineural hearing loss caused by STRC biallelic variation. Methods: A child with hearing impairment who was diagnosed at Gansu Provincial Maternal and Child Health Hospital on May 2022 and was selected as the research object. Peripheral blood of the child and her parents was collected, genomic DNA was extracted. IDT The xGen Exome Research Panel v2.0 whole exome capture chip was used to capture and sequence. Bioinformatics and clinical information analysis technology were used to analyze genetic data. The suspected pathogenic mutations were verified by quantitative polymerase chain reaction(QPCR)and Sanger sequencing. Results: The child had moderate hearing loss at about 1 year and 10 months, and now she is 3 years and 6 months, the hearing loss has not worsened. Whole exome sequencing(WES) testing revealed that the child carried the STRC gene with a deletion in EXON:1-29 and variants c.4561(exon24) _c.4562(exon24)insC, inherited from the mother and father, respectively. According to the relevant guidelines of the American Society for Medical Genetics and Genomics (ACMG), they were determined to be likely pathogenic variant and pathogenic variant. Conclusion: The discovery of c.4561(exon24) _c.4562(exon24)insC enriched the STRC variation spectrum, and provided a theoretical basis for the diagnosis and genetic counseling to the children.
目的： 探讨STRC双等位基因变异导致非综合征型感音神经性听力损失的遗传学特点。 方法： 以2022年5月就诊于甘肃省妇幼保健院的1例女性听力障碍患儿作为研究对象，采集患儿及父母外周血，抽提基因组DNA，用IDT The xGen Exome Research Panel v2.0全外显子（exon）捕获芯片捕获并测序，运用生物信息学及临床信息分析技术进行基因数据分析，对疑似致病变异用定量聚合酶链式反应（quantitative polymerase chain reaction，QPCR）和Sanger测序进行验证。 结果： 患儿出生时听力初筛瞬态诱发耳声发射（TEOAE）双耳未通过，42 d以及4月龄听力复筛均未通过，1岁10个月时检测发现左右耳均为中度感音神经性听力损失，现3岁6个月，听力损失无加重。全外显子组测序检测显示患儿携带STRC基因exon 1-29del和c.4561（exon 24）_c.4562（exon 24）insC变异，分别遗传自母亲和父亲，后者为新变异。根据美国医学遗传学与基因组学学会（American College of Medical Genetics and Genomics，ACMG）相关指南，分别判定为可能致病变异和致病变异。 结论： c.4561（exon 24）_c.4562（exon 24）insC变异的发现丰富了STRC基因致病变异谱，可为患儿听力损失的诊断和遗传咨询提供理论依据。.