To Örebro University

Importance: The genetic variation in patients with sensorineural hearing loss (SNHL) in the Nordic countries has not been previously reported.

Objectives: The aim was to describe the genetic variation in a Swedish population and identify factors in favor of a high diagnostic yield.

Design: This was a prospective cohort study. Children with bilateral SNHL and adults with bilateral SNHL and clinically suspected genetic SNHL underwent genetic testing. A gene panel with similar to 200 genes was applied on whole genome sequencing (WGS) data. Variants were classified according to American College of Medical Genetics and Genomics criteria. Personal health data were extracted from medical records.

Setting and Participants: Eighty-five patients (aged 0-73 years) from Lund and Orebro University Hospitals, 2 tertiary referral centers for audiology in Sweden, with mild to profound SNHL.

Results: In almost half (45%, n = 38) of the cases, a genetic cause was identified across 24 different genes. Eleven cases had syndromic hearing loss. A majority (n = 57) had prelingual onset (<2 years) of SNHL and most of them had moderate-to-profound hearing loss (n = 52). Prelingual onset was associated with higher yield than postlingual onset (OR 6.3, 95% CI 2.1-19.0). In patients with moderate-profound prelingual SNHL, the diagnostic yield was 60% (n = 31/52).

Conclusion: This is the first reported cohort of hearing loss patients undergoing genetic testing with WGS from a Nordic country. Early onset of hearing loss favored a higher diagnostic yield than postlingual, and a genetic cause was found in a majority of cases in patients with prelingual, moderate-to-profound SNHL.