# Genomic Biomarkers and Mutational Landscape of Nonsyndromic Hearing Loss (NSHL) in the Singaporean Population: Clinical Translational Implications

## TL;DR

This study identifies genetic biomarkers for nonsyndromic hearing loss in Singaporeans, revealing key genes and variants linked to different hearing loss severities.

## Contribution

The study expands the mutational spectrum of NSHL in Singaporeans and identifies novel variants with clinical implications.

## Key findings

- A molecular diagnosis was achieved in 57% of NSHL cases with high pathogenic variant classification.
- Common and novel genes like GJB2, SLC26A4, and MYO6 were linked to specific hearing loss severities.
- The findings support improved diagnosis and precision medicine approaches for hearing loss in Singapore.

## Abstract

Nonsyndromic hearing loss (NSHL) is a highly prevalent, genetically heterogeneous condition, yet its molecular basis in the Singaporean population remains underexplored. We performed whole-exome sequencing and integrative bioinformatics analysis in 115 patients with NSHL to define population-specific genetic biomarkers. A molecular diagnosis was achieved in 57% of cases, with 76% of identified variants classified as pathogenic or likely pathogenic and 24% exhibiting high pathogenic potential. Common East Asian NSHL genes, including GJB2, SLC26A4, and OTOF, were frequently detected alongside less prevalent genes such as ACTG1, CEACAM16, COL11A2, DIAPH1, KCQN4, MYH14, MYO6, MYO7A, MYO15A, SLC17A8, SMPX, STRC, TJP2, TMC1, TMPRSS3, highlighting extensive genetic heterogeneity. Notably, multiple novel variants, including MYO6 c.554-2A>G, and TNC p.N750Y, were identified, expanding the known mutational spectrum of NSHL. Genotype–phenotype correlations revealed that GJB2 variants were primarily associated with mild to moderate hearing loss, whereas SLC26A4 variants correlated with severe to profound phenotypes in the Singaporean populations. Collectively, our study provides important insights into the genetic architecture of NSHL in Singapore’s population. In addition, it supports improved molecular diagnosis yield and informed clinical management decisions as well as the advancement of precision medicine approaches aimed at reducing the burden of hearing loss in the region.