목적: Sensorineural hearing impairment (SNHI) is the most common inherited sensory defect, affecting about 3 per 1000 children. Over 50% of these patients have genetic causes (i.e. hereditary hearing impairment HHI). HHI is very heterogeneous etiologically, with >240 deafness genes discovered to date. Mutations in specific genes were noted to be extraordinarily popular in deaf patients across different populations, making molecular screening feasible for these common deafness genes. Recently, the advent of next-generation sequencing (NGS) has revolutionized the clinical evaluation of hearing-impaired patients by making comprehensive genetic testing possible. 방법:We aimed to study the prevalence of hearing-related gene mutations and the clinical correlation of idiopathic deafness among the Mongolian population by expanding the clinical cohort study group and upgrading the genetic analysis platform using NGS techniques. 결과:The study was conducted between 2021-2024, and a detailed WES analysis was performed in 84 (80.7%) of 104 patients with hearing loss history in the family, changes detected on CT scans and suspected of other disease or syndromic disease and in 20 (19.3%) cases, NGS analysis performed. There were 52 mutational variants of 27 types of genes in 57 (54.8%) patients, of which 39 were confirmed/candidate variants and 29 were novel variants. Gene mutation analysis of a total of 16 patients with EVA, Mondini malformation, and inner ear malformation in TBCT scan showed bi-allelic SLC26A4 gene mutation in 12 (75%) of which 31.3(10/32) had the c.919-2A>G variant. 결론:A patient with clinically suspected Waardenburg syndrome had the SOX10 c.393C>G (p.N131K) mutation, which has been studied to be common in Africans and African Americans, and CHD7: c.2594dupA (p. N866Efs*8) mutation was detected in a patient with suspected CHARGE syndrome, each genotype was confirmed. Our study, using NGS and WES methods, identified confirmed/ candidate variants, many novel variants, and rare gene mutations that occur in Asian and Indian populations, indicating a unique variant spectrum in the Mongolian population.