Girotto Giorgia, Morgan Anna, Krishnamoorthy Navaneethakrishnan, Cocca Massimiliano, Brumat Marco, Bassani Sissy, La Bianca Martina, Di Stazio Mariateresa, Gasparini Paolo
Department of Medicine, Surgery and Health Sciences, University of Trieste, Trieste, Italy.
Institute for Maternal and Child Health - IRCCS "Burlo Garofolo", Trieste, Italy.
Front Genet. 2019 Feb 26;10:142. doi: 10.3389/fgene.2019.00142. eCollection 2019.
Age-related hearing loss (ARHL) is the most common sensory impairment in the elderly affecting millions of people worldwide. To shed light on the genetics of ARHL, a large cohort of 464 Italian patients has been deeply characterized at clinical and molecular level. In particular, 46 candidate genes, selected on the basis of genome-wide association studies (GWAS), animal models and literature updates, were analyzed by targeted re-sequencing. After filtering and prioritization steps, has been identified as a strong candidate and then validated by " and studies. Briefly, a rare (MAF: 2.886e-5) missense variant c.539G > A, p.(R180Q) was detected in two unrelated male patients affected by ARHL characterized by a severe to profound high-frequency hearing loss. The variant, predicted as damaging, was not present in healthy matched controls. Protein modeling confirmed the pathogenic effect of p.(R180Q) variant on protein's structure leading to a change in the total number of hydrogen bonds. hybridization showed expression in zebrafish inner ear. A zebrafish knock-in model, generated by CRISPR-Cas9 technology, revealed a reduced auditory response at all frequencies in mutants compared to and animals. Moreover, a significant reduction (5.8%) in the total volume of the saccular otolith (which is responsible for sound detection) was observed in compared to ( = 0.0014), while the utricular otolith, necessary for balance, was not affected in agreement with the human phenotype. Overall, these data strongly support the role of gene in the pathogenesis of ARHL opening new perspectives in terms of diagnosis, prevention and treatment.
年龄相关性听力损失（ARHL）是老年人中最常见的感觉障碍，影响着全球数百万人。为了深入了解ARHL的遗传学，对一大群464名意大利患者进行了临床和分子水平的深度特征分析。特别是，基于全基因组关联研究（GWAS）、动物模型和文献更新选择的46个候选基因，通过靶向重测序进行了分析。经过筛选和优先级排序步骤，已被确定为一个强有力的候选基因，然后通过“和”研究进行了验证。简而言之，在两名患有以严重至极重度高频听力损失为特征的ARHL的无关男性患者中检测到一种罕见的（MAF：2.886e-5）错义变体c.539G>A，p.（R180Q）。该变体被预测为有害，在健康匹配对照中不存在。蛋白质建模证实了p.（R180Q）变体对蛋白质结构的致病作用，导致氢键总数发生变化。杂交显示在斑马鱼内耳中有表达。通过CRISPR-Cas9技术生成的斑马鱼敲入模型显示，与和动物相比，突变体在所有频率下的听觉反应均降低。此外，与相比，在中观察到球囊耳石的总体积显著减少（减少5.8%）（=0.0014），而对平衡至关重要的椭圆囊耳石未受影响，这与人类表型一致。总体而言，这些数据有力地支持了基因在ARHL发病机制中的作用，为诊断、预防和治疗开辟了新的前景。
