A Systematic Review on Heritability of Sudden Sensorineural Hearing Loss

ObjectiveTo assess the evidence supporting the heritability and genetic basis of sudden sensorineural hearing loss (SSNHL).Data SourceRecords were extracted from PubMed, Scopus, and Cochrane databases.Review MethodsThe protocol was registered on PROSPERO (CRD42022357389) and includes a systematic review on the genetic contribution to SSNHL. The search strategy yielded 1.483 articles from electronic databases. After quality assessment, 34 records were selected, including 369.650 patients with SSNHL from nine prevalence studies, two familial aggregation studies, one twin study, and 22 genetic studies. The prevalence of SSNHL was calculated from data on its incidence from population-based studies (period prevalence). To evaluate the heritability of SSNHL, the sibling recurrence risk ratio (lambda s) was calculated, by comparing the prevalence of SSNHL among siblings within the same generation to the estimated prevalence in the overall population. Genetic variants were grouped, based on the pathological mechanism related to SSNHL.ResultsThe prevalence of SSNHL ranged from 0.1% to 0.0003% in America to 0.12%-0.0093% in Asia. The estimated sibling recurrence risk ratio for SSNHL (lambda s = 20.8-83.3) supports a significant familial aggregation. Although several genetic variants were reported to be associated with SSHL in controlled studies, neither was replicated in an independent cohort.ConclusionsEvidence supporting heritability of SSNHL is limited to epidemiological studies showing prevalence differences across different populations and familial aggregation. Genetic studies are of low quality and they lack replication cohort to confirm their findings. According to its low prevalence, exome or genome sequencing familial-based studies are needed to identify rare genetic variants in SSNHL.Level of EvidenceNA Laryngoscope, 2024