Hereditary hearing impairment (HHI) is a common but heterogeneous clinical entity caused by mutations in a plethora of deafness genes. Research over the past few decades has shown that the genetic epidemiology of HHI varies significantly across populations. In this study, we used different genetic examination strategies to address the genetic causes of HHI in a large Taiwanese cohort composed of >5000 hearing-impaired families. We also analyzed the clinical features associated with specific genetic mutations. Our results demonstrated that next-generation sequencing-based examination strategies could achieve genetic diagnosis in approximately half of the families. Common deafness-associated genes in the Taiwanese patients assessed, in the order of prevalence, included GJB2, SLC26A4, OTOF, MYO15A, and MTRNR1, which were similar to those found in other populations. However, the Taiwanese patients had some unique mutations in these genes. These findings may have important clinical implications for refining molecular diagnostics, facilitating genetic counseling, and enabling precision medicine for the management of HHI.

Genetic factors are an important cause of idiopathic sensorineural hearing impairment (SNHI). From the epidemiological perspective, mutations of three deafness genes: GJB2, SLC26A4, and MT-RNR1, are much more prevalent than those of other genes worldwide. However, mutation spectra of common deafness genes differ remarkably across different populations. Here, we performed comprehensive genetic examination and haplotype analyses in 188 unrelated Mongolian families with idiopathic SNHI, and compared their mutation spectra and haplotypes to those of other European and Asian cohorts. We confirmed genetic diagnoses in 18 (9.6%) of the 188 families, including 13 with bi-allelic GJB2 mutations, three with bi-allelic SLC26A4 mutations, and two with homoplasmic MT-RNR1 m.1555A>G mutation. Moreover, mono-allelic mutations were identified in 17 families (9.0%), including 14 with mono-allelic GJB2 mutations and three with mono-allelic SLC26A4 mutations. Interestingly, three GJB2 mutations prevalent in other populations, including c.35delG in Caucasians, c.235delC in East Asians, and c.-23+1G>A in Southwest and South Asians, were simultaneously detected in Mongolian patients. Haplotype analyses further confirmed founder effects for each of the three mutations, indicating that each mutation derived from its ancestral origin independently. By demonstrating the unique spectra of deafness-associated mutations, our findings may have important clinical and scientific implications for refining the molecular diagnostics of SNHI in Mongolian patients, and for elucidating the genetic relationships among Eurasian populations.

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Objective: To compare the clinical characteristics and treatment results of different clinical types of benign paroxysmal positional vertigo (BPPV). Methods: A total of 162 patients diagnosed with BPPV between January 2019 to January 2021 at EMJJ ENT Hospital's vestibular laboratory in Mongolia were included in our study. The diagnosis of BPPV was made according to the 2017 AAO-HNS clinical practice guideline for BPPV. Clinical questionnaires, Dizziness Handicap Inventory (DHI) questionnaires, and videonystgamography were obtained for all patients. Results: From a total of 162 patients diagnosed as BPPV, 62.4% had posterior canal BPPV, 27.1% had horizontal canal BPPV, and 10.5% had anterior canal BPPV. Fischer's exact test showed a higher incidence on the right side (p = 0.000). The mean age 50 ± 11.7; the male to female ratio 1:4. When the relationship between the effectiveness and duration of the treatment was assessed, 123 (75.9%) recovered after 7 days. DHI score after treatment signi cantly after treatment (p = 0.000) regardless of the clinical type. Conclusions: Patients who had a longer duration of symptoms underwent unnecessary diagnostic tests and developed additional psychologic problems. There were no statistically signi cant differences when we compared the characteristics and treatment between the three clinical types of BPPV.