Molecular testing for the study of non-syndromic hearing loss

Objective: Hearing loss (HL) is the most common sensory disorder, with more than 460 millions of people affected worldwide. Among the genetic cases of HL, Non-Syndromic Hearing Loss (NSHL) accounts for the majority of them, and its diagnosis still represents a challenge for both clinicians and geneticists. In the present work we reviewed the current approaches employed for the genetic study of this heterogeneous disorder, providing specific recommendations intended to help scientists in reaching the correct molecular diagnosis in NSHL patients. Methods: A review of the most widespread approaches for the study of NSHL has been performed, with an eye on the common difficulties that geneticists and clinicians can encounter in the diagnostic process. Results: An accurate clinical evaluation together with the application of a multi-step approach, based on next-generation sequencing technologies and copy number variations assays, represents the most effective strategy for the molecular diagnosis of NSHL. Conclusion: NSHL is a high genetically heterogeneous condition that required proper technological platforms, as well as trained staff with a deep knowledge of its genetic background for the identification of the correct molecular diagnosis.