Bilateral sudden sensorineural hearing loss following COVID-19 infection has rarely been reported. We encountered a 34-year-old patient with bilateral profound sensorineural loss after COVID-19 infection. After disappointing therapeutic result of high dose steroid therapy and intratympanic steroid injection, the patient experienced satisfactory auditory rehabilitation with bilateral cochlear implantation.

Bilateral sudden sensorineural hearing loss following COVID-19 infection has rarely been reported. We encountered a 34-year-old patient with bilateral profound sensorineural loss after COVID-19 infection. After disappointing therapeutic result of high dose steroid therapy and intratympanic steroid injection, the patient experienced satisfactory auditory rehabilitation with bilateral cochlear implantation.

Bilateral sudden sensorineural hearing loss following COVID-19 infection has rarely been reported. We encountered a 34-year-old patient with bilateral profound sensorineural loss after COVID-19 infection. After disappointing therapeutic result of high dose steroid therapy and intratympanic steroid injection, the patient experienced satisfactory auditory rehabilitation with bilateral cochlear implantation.

Bilateral sudden sensorineural hearing loss following COVID-19 infection has rarely been reported. We encountered a 34-year-old patient with bilateral profound sensorineural loss after COVID-19 infection. After disappointing therapeutic result of high dose steroid therapy and intratympanic steroid injection, the patient experienced satisfactory auditory rehabilitation with bilateral cochlear implantation.

Bilateral sudden sensorineural hearing loss following COVID-19 infection has rarely been reported. We encountered a 34-year-old patient with bilateral profound sensorineural loss after COVID-19 infection. After disappointing therapeutic result of high dose steroid therapy and intratympanic steroid injection, the patient experienced satisfactory auditory rehabilitation with bilateral cochlear implantation.

Purpose: To assess the diagnostic potential of whole-exome sequencing (WES) and elucidate the clinical and genetic characteristics of primary ciliary dyskinesia (PCD) in the Korean population. Materials and Methods: Forty-seven patients clinically suspected of having PCD were enrolled at a tertiary medical center. WES was performed in all patients, and seven patients received biopsy of cilia and transmission electron microscopy (TEM). Results: Overall, PCD was diagnosed in 10 (21.3%) patients: eight by WES (8/47, 17%), four by TEM. Among patients diagnosed as PCD based on TEM results, two patients showed consistent results with WES and TEM of PCD (2/4, 50%). In addition, five patients, who were not included in the final PCD diagnosis group, had variants of unknown significance in PCD-related genes (5/47, 10.6%).The most frequent pathogenic (P)/likely pathogenic (LP) variants were detected in DNAH11 (n=4, 21.1%), DRC1 (n=4, 21.1%), and DNAH5 (n=4, 21.1%). Among the detected 17 P/LP variants in PCD-related genes in this study, 8 (47.1%) were identified as novel variants. Regarding the genotype–phenotype correlation in this study, the authors experienced severe PCD cases caused by the LP/P variants in MCIDAS, DRC1, and CCDC39. Conclusion Through this study, we were able to confirm the value of WES as one of the diagnostic tools for PCD, which increases with TEM, rather than single gene tests. These results will prove useful to hospitals with limited access to PCD diagnostic testing but with relatively efficient in-house or outsourced access to genetic testing at a pre-symptomatic or early disease stage.

Background: Mutations in mitochondrial DNA (mtDNA) are associated with several genetic disorders, including sensorineural hearing loss. However, the prevalence of mtDNA mutations in a large cohort of Korean patients with hearing loss has not yet been investigated. Thus, this study aimed to investigate the frequency of mtDNA mutations in a cohort of with pre- or post-lingual hearing loss of varying severity. Methods: A total of 711 Korean families involving 1,099 individuals were evaluated. Six mitochondrial variants associated with deafness (MTRNR1 m.1555A>G, MTTL1 m.3243A>G, MTCO1 m.7444G>A and m.7445A>G, and MTTS1 m.7471dupC and m.7511T>C) were screened using restriction fragment length polymorphism. The prevalence of the six variants was also analyzed in a large control dataset using whole-genome sequencing data from 4,534 Korean individuals with unknown hearing phenotype. Results: Overall, 12 of the 711 (1.7%) patients with hearing loss had mtDNA variants, with 10 patients from independent families positive for the MTRNR1 m.1555A>G mutation and 2 patients positive for the MTCO1 m.7444G>A mutation. The clinical characteristics of patients with the mtDNA variants were characterized by post-lingual progressive hearing loss due to the m.1555A>G variant (9 of 472; 1.9%). In addition, 18/4,534 (0.4%) of the Korean population have mitochondrial variants associated with hearing loss, predominantly the m.1555A>G variant. Conclusion A significant proportion of Korean patients with hearing loss is affected by the mtDNA variants, with the m.1555A>G variant being the most prevalent. These results clarify the genetic basis of hearing loss in the Korean population and emphasize the need for genetic testing for mtDNA variants.

Objectives: . Noise exposure leads to an increase in the macrophage population. This increment is thought to be caused by the transformation of infiltrated monocytes into macrophages rather than by proliferation of the cochlear resident macrophages. However, studies on infiltrated monocytes in the cochlea are scarce. Thus, we aimed to investigate the infiltration of monocytes and their transformation into macrophages after noise exposure. Methods: . In wild-type and CX3CR1+/GFP C57/B6 mice, inflammatory monocytes were identified by immunofluorescence of mouse cochlear cells. The findings were confirmed and quantitated by flow cytometry. Results: . One day after noise exposure, monocytes were identified in the spiral ligament. Flow cytometric analysis confirmed that the monocyte population peaked on post-noise exposure day 1 and decreased thereafter. On day 3 after noise exposure, amoeboid-type macrophages increased in the crista basilaris, and on day 5, they spread to the basilar membrane. Conclusion . Infiltrated monocytes were successfully observed 1 day after noise exposure, preceding the increase in the macrophage population. This finding supports the proposal that infiltrated monocytes transform into macrophages.