National Research Centre for Audiology and Hearing Rehabilitation, Moscow, 117513, Russia; Russian Medical Academy for Continuous Professional Training, Moscow, 125993, Russia.
Research Centre for Medical Genetics, Moscow, 115478, Russia.
Int J Pediatr Otorhinolaryngol. 2020 Nov;138:110247. doi: 10.1016/j.ijporl.2020.110247. Epub 2020 Jul 19.
Congenital sensorineural hearing loss is related to mutations in numerous genes encoding the structures of the inner ear in majority of the cases. Mutations in GJB2 gene are the most frequently identified causes of congenital nonsyndromal hearing loss. GJB2 gene testing became a routine clinical tool. For GJB2-negative patients new genetic approaches including methods based on new generation sequencing give a chance to identify mutations in other genes. The frequent reason of mild-to-moderate hearing loss such as the deletions/mutations of the gene STRC encoding stereocilin protein were recognized (OMIM: 606440).
To evaluate the audiological features in hearing impaired patients with deletions and point mutations in the STRC gene.
The group of 28 patients from 21 unrelated families with pathological mutations in the STRC gene underwent audiological examination. The description and analysis of the results of full audiological examination was provided.
All patients initially had bilateral nonsyndromal sensorineural hearing loss. Among 11 homozygotes of large deletion harboring STRC to CATSPER2 genes were 7 male individuals indicating the presence of male infertility syndrome. In general, 7 children failed audiological screening and 4 children underwent audiological assessment in the age of 3 and 6 months. The most frequently hearing thresholds were registered between 35 and 55 dB that corresponds to mild-to-moderate hearing impairment. The average age of diagnostics was 7.9 years (ranged from 3 months to 45 years). In the majority of patients the audiological profiles were flat or descending with elevation of thresholds at middle and high frequencies and relatively preserved thresholds at low frequencies. Hearing thresholds are symmetric and stable with age.
STRC-linked hearing loss is congenital, of mild and moderate severity. Special clinical and genetic approach for children who failed newborn hearing screening with mild-to-moderate hearing loss is necessary.
评估 STRC 基因缺失和点突变致听力受损患者的听力学特征。
21 个无关家系的 28 例 STRC 基因病理性突变患者接受了听力学检查。对全听力学检查结果进行了描述和分析。
所有患者最初均为双侧非综合征性感觉神经性听力损失。11 例携带 STRC 至 CATSPER2 基因大片段缺失的纯合子中，有 7 例为男性，提示存在男性不育综合征。总体而言，7 例患儿未通过听力筛查，4 例患儿在 3 月龄和 6 月龄时进行了听力评估。最常见的听力阈值在 35 至 55dB 之间，对应于轻度至中度听力障碍。诊断的平均年龄为 7.9 岁（范围为 3 个月至 45 岁）。在大多数患者中，听力学特征为平坦或下降型，中频和高频阈值升高，低频阈值相对保留。听力阈值随年龄增长而对称且稳定。
STRC 相关听力损失为先天性，程度为轻度至中度。对于新生儿听力筛查未通过且有轻度至中度听力损失的儿童，需要进行特殊的临床和遗传方法评估。
