A Novel Frameshift Mutation of the USH2A Gene in a Korean Patient with Usher Syndrome Type II

Usher syndrome type II (USH2) is the most common form of Usher syndrome, characterized by moderate to severe hearing impairment and progressive visual loss due to retinitis pigmentosa. It has been shown that mutations in the USH2A gene are responsible for USH2. The authors herein describe a 34-year-old Korean woman with the typical clinical manifestation of USH2; she had bilateral hearing disturbance and progressive visual deterioration, without vestibular dysfunction. Molecular genetic study of the USH2A gene revealed a novel frameshift mutation (c.2310delA; Glu771LysfsX17). She was heterozygous for this mutation, and no other mutation was found in USH2A, suggesting the possibility of an intronic or large genomic rearrangement mutation. To the best of our knowledge, this is the first report of a genetically confirmed case of USH2 in Korea. More investigations are needed to delineate genotype-phenotype correlations and ethnicity-specific genetic background of Usher syndrome.

Standardization for a Korean Adaptation of the International Outcome Inventory for Hearing Aids: Study of Validity and Reliability / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The evaluation of subjective outcomes of hearing aid fitting is of paramount importance along with audiometric improvement. The aim of this study was to develop a Korean adaptation of the International Outcome Inventory for Hearing Aids (IOI-HA) and to determine its reliability and validity. SUBJECTS AND METHOD: The translation of IOI-HA into the Korean version (K-IOI-HA) was completed through a process of forward translation, reconciliation, reverse translation and cognitive debriefing. K-IOI-HA was administered to 101 patients using hearing aids and visiting any the 10 referral hospitals. Reliability was evaluated by Cronbach's alpha coefficient and by test-retest analysis. Validity was assessed by confirmatory factor analysis and criterion validity based on the results of pure tone audiometry. RESULTS: K-IOI-HA showed a good internal consistency (Cronbach's alpha=0.83) and a high test-retest reliability (r=0.943, p<0.01). Validity checked by confirmatory factor analysis also showed good construct validity. CONCLUSION: The Korean version of IOI-HA is a reliable and valid tool for evaluating subjective outcomes of hearing aids.

Standardization for a Korean Version of Chronic Ear Survey: Translation and Verification of Validity and Reliability / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The Chronic Ear Survey (CES) has been known to be a valid, disease-specific measure for the evaluation of health status and treatment effectiveness for chronic otitis media patients. As part of this study, we developed a Korean version by adapting from this CES, determined its reliability and validity. MATERIALS AND METHOD: The development of the Korean version of CES (K-CES) included the processes of standard independent translation and cross-cultural adaptation to check for cultural inconsistency. The finalized K-CES was administered to 166 patients visiting 10 referral hospitals in a prospective manner. K-CES was validated by using the Cronbach's alpha coefficient, confirmatory factor analysis and test-retest analysis for reliability and validity. The 36-Item Short Form Health Survey Instrument (SF-36) was assessed and the result was used to evaluate the criterion validity. RESULTS: The K-CES demonstrated good test-retest reliability and internal consistency (Cron-bach's alpha=0.850). Scale-item correlation coefficient was even higher than 1.0, which shows a very high reliability of K-CES. The validity of K-CES, checked by confirmatory factor analysis, also showed good construct validity. There was high correlation between SF-36 and the scores of K-CES, which indicates high criterion validity. CONCLUSION: We concluded that K-CES is a valid tool for clinical use and research studies in Korean patients with chronic otitis media.

Hearing Outcomes According to the Types of Mastoidectomy: A Comparison between Canal Wall Up and Canal Wall Down Mastoidectomy

OBJECTIVES: The aim of this study was to compare the hearing outcomes between canal wall up mastoidectmy (CWUM) and canal wall down mastoidectmy (CWDM). METHODS: One hundred seventy one chronic suppurative otitis media (CSOM) patients were enrolled in this retrospective study. The patients who underwent the second staged ossiculoplasty at least 6 months after mastoidectomy and who had an intact, well aerated tympanic cavity as well as intact mobile stapes at the time of operation were selected from the medical record. Based on the type of mastoid surgery, the patients were categorized into two groups: the CWUM (n=38) and CWDM groups (n=133). The hearing results of the CWUM and CWDM groups were compared using the pre- and post-operative air-bone gap (ABG) at 3 months after ossiculoplasty. RESULTS: The preoperative ABG in both groups (CWUM and CWDM) were 28.4+/-15.6 dB and 31.8+/-14.5 dB, respectively (P=0.18). Both groups didn't show any significant difference (10.9 dB vs. 13.5 dB, respectively) (P=0.21) for the postoperative ABG closure. The proportion of patients with an ABG less than 20 dB was 58.6% of the CWDM patients and 68.4% of the CWUM patients (P=0.25). CONCLUSION: The type of mastoid surgery (CWUM and CWDM) did not affect the hearing results of CSOM patients. When choosing the type of mastoidectomy procedure for CSOM surgery, the hearing outcomes are basically the same for both types of procedure.

Sequence Variations and Haplotypes of the GJB2 Gene Revealed by Resequencing of 192 Chromosomes from the General Population in Korea

OBJECTIVES: Hearing impairment (HI) is the most common sensory deficit in human. The Gap Junction Protein, Beta-2 (GJB2) gene encodes the protein connexin 26, and this gene accounts for up to half of the cases of autosomal recessive nonsyndromic HI. This study was conducted to obtain a set of sequence variations (SVs) of the GJB2 gene among Koreans from the general population for making molecular genetic diagnoses and performing genetic counseling. METHODS: We resequenced the GJB2 gene in 192 chromosomes from 96 adult individuals of Korean descent and who were without a history of hearing difficulty. The data of the SVs was obtained and the haplotypes were reconstructed from the data. RESULTS: Five SVs were observed, including a novel one (c.558G>A; p.T186T), with the allele frequencies ranging from 0.5% (1/192) to 41% (79/192). The linkage disequilibrium study and haplotype construction showed that some of the SVs are in tight linkage, resulting in a limited number of haplotypes. CONCLUSION: We observed SVs of the GJB2 gene with different allele frequencies, and a limited number of haplotypes were constructed. The data from this study can be used as reference data for GJB2-related hearing genetic studies, including studies on the founder effect and population genetics, and this data is particularly relevant to people of East Asian decent.