Unraveling the propensity of various genetic disorders and syndromes in the Koraga, an aboriginal tribe from southern India.

Koragas, recognized as a particularly vulnerable tribal group (PVTG) by the Government of India, are from coastal Karnataka and Kerala. They are experiencing severe socioeconomic and health-related issues and rapid depopulation. The unique genetic makeup of Koragas has been maintained by the practice of endogamy. We aimed to identify genetic factors potentially associated with the predisposition of Koragas towards genetic and multifactorial disorders. We employed genome-wise data of 29 Koraga individuals genotyped on the Infinium Global Screening Array-24 v3.0 BeadChip platform and performed various population genetic analyses including kinship, identity by descent (IBD), and runs of homozygosity (RoH). A high degree of haplotype sharing among the Koraga participants may be indicative of a recent founder event. We identified genetic variants and genes associated with several genetic disorders, higher infant mortality rate, neurological disorders, deafness, and lower fertility rate of this agrarian tribe. Ours is the first genome-wide study on the Koraga tribe that identified genetic factors associated with various genetic disorders. Our findings can provide public healthcare providers with essential genetic information that can be useful in augmenting medical and healthcare services and improving the quality of life of Koragas.

Examining the Language and Communication Factors of a Deaf Child with Autism Spectrum Disorder from an Immigrant Korean Family.

Extant research on learners who are d/Deaf or hard of hearing with disabilities who come from Asian immigrant families is extremely sparse. The authors conducted an intrinsic case study of a deaf student with autism who comes from a Korean immigrant family. To acquire a comprehensive understanding of language and communication characteristics, they analyzed (a) interview data of three administrators who worked with the student and family and (b) school documents/reports issued to the parents. Themes are reported across the three components of the tri-focus framework (Siegel-Causey & Bashinski, 1997): the learner, partner, and environment. Implications for practitioners who work with these learners and their families are discussed, including (a) compiling an individualized language and communication profile that encompasses the framework; (b) utilizing culturally and linguistically responsive practices with the family; (c) practicing interprofessional collaboration; and (d) modifying physical and social environments to increase accessibility.

MPZL2-a common autosomal recessive deafness gene related to moderate sensorineural hearing loss in the Chinese population.

BACKGROUND: Mutations in MPZL2, the characteristic genetic etiology of autosomal recessive deafness loci 111 (DFNB111), cause non-syndromic and moderate sensorineural hearing loss. METHODS: In this study, we analyzed the phenotype and genotype of eight pedigrees consisting of 10 hearing loss patients with bi-allelic pathogenic or likely pathogenic variants in MPZL2. These patients were identified from a 3272 Chinese patient cohort who underwent genetic testing. RESULTS: Apart from symmetrical and moderate sensorineural hearing loss, the MPZL2-related phenotype was characterized by progressive hearing loss with variation in the onset age (congenital defect to onset at the young adult stage). We determined that in the Chinese population, the genetic load of MPZL2 defects was 0.24% (8/3272) in patients diagnosed with hearing loss and 7.02% (8/114) in patients diagnosed with hereditary moderate sensorineural hearing loss caused by STRC, OTOA, OTOG, OTOGL, TECTA, MPZL2 and others. Three known MPZL2 variants (c.220C > T (p.Gln74*), c.68delC (p.Pro23Leufs*2), c.463delG (p.Ala155Leufs*10)) and a novel start loss variant (c.3G > T (p.Met1?)) were identified. MPZL2 c.220C > T was identified as the hotspot variant in the Chinese population and even in East Asia compared with c.72delA (p.Ile24Metfs*22) in European and West Asia through allele frequency. CONCLUSIONS: We concluded that apart from moderate HL, progressive HL is another character of MPZL2-related HL. No specified variant was verified for the progression of HL, the penetrance and expressivity cannot be determined yet. A novel MPZL2 variant at the start codon was identified, enriching the variant spectrum of MPZL2. The hotspot variants of MPZL2 vary in different ethnicities. This study provides valuable data for the diagnosis, prognosis evaluation and genetic counseling of patients with moderate sensorineural hearing loss related to MPZL2.

Health disparities among Black deaf and hard of hearing Americans as compared to Black hearing Americans: A descriptive cross-sectional study.

ABSTRACT: There is a dearth of literature on health outcomes for Black people who identify as deaf or hard of hearing (DHH). Black DHH individuals generally experience at least 2 types of oppression, racism and audism, both of which contribute to health disparities within the Black and Deaf communities.To understand the prevalence of health outcomes in a Black DHH adult sample and compare this to a Black hearing sample.A descriptive cross-sectional study with primary Health Information National Trends Survey (HINTS)- American Sign Language survey data from Black DHH adults and secondary National Cancer Institute-HINTS English survey data from Black hearing adults.Black DHH adults and Black hearing adults (18 years or older).Using NCI's health information national trends survey in American Sign Language and English, self-reported data was gathered for all medical conditions as diagnosed by healthcare providers.The study showed that Black DHH adults had a higher likelihood for diabetes, hypertension, lung disease, cancer, and comorbidity compared to their hearing Black counterparts.Black DHH adults are at disparity for certain medical conditions compared to the general Black adult population. Future directions are needed to ensure that anti-racist policies include consideration of people with sensory disabilities. Inclusion of cultural and language needs of Black DHH patients in cultural humility training for healthcare providers is recommended to address health disparity in this population.

Emotion as Motivator: Parents, Professionals and Diagnosing Childhood Deafness.

Diagnosing deafness is a culturally situated practice generating considerable research in health sciences but limited work in anthropology. Diagnosis fast-tracks parents into a medical and education pathway but can also create tension for parents and professionals. Drawing on ethnographic fieldwork, we argue that in this biomedical context, emotions are often understood by professionals as impairing for parents, and hence problematic for the treatment process. In contrast emotions are characterized by parents as motivational and tools for decision making on a pathway that is experienced as a source of stress.

Combined hearing screening and genetic screening of deafness among Hakka newborns in China.

OBJECTIVE: Hearing loss (HL) can severely impact the quality of human life. To explore strategies for clinical interventions, we investigated hearing screening coupled with genetic testing of deafness among Hakka newborns. METHODS: The testing was performed on 4205 newborns who born in Heyuan of Guangdong province between December 2018 and November 2019. Hearing screening used otoacoustic emission(OAE) coupled with automatic auditory brainstem response(AABR). A total of 13 hot spot mutations in GJB2, SLC26A4, mtDNA, and GJB3 genes were screened using PCR accompanied by flow-through hybridization technology. RESULTS: Among the 4205 newborns, the number of 47 individuals who failed the hearing testing accounted for 1.12％(47/4205). The genetic screening displayed that 176 individuals(4.19%,176/4205) discovered to carry more than one mutant site. The gene carrier frequency of GJB2, SLC26A4, GJB3, and mtDNA was 2.24%, 1.76%, 0.19%, and 0.07% respectively. The most carried mutations were GJB2 c.235del (2.05%), followed by SLC26A4 c.IVS7-2A > G(1.38%). A total of 216 (5.14%, 216/4205) high-risk children detected by combined hearing screening and genetic screening of deafness. Pairwise comparison (1.12% vs 4.19% vs 5.14%) showed significant differences for the positive rate of detection(χ 2 = 11.045, P < 0.001). The difference was no statistical significance between neonatal demographics information and genetic mutations using logistic regression analysis(all P > 0.05). CONCLUSIONS: Among Hakka newborns in Heyuan, the carrier rate of GJB2 c.235delC was the highest. Combining with two screening methods will effectually increase the detection rate of neonatal deafness and play an essential role in clinical intervention.

Screening for deafness-associated mitochondrial 12S rRNA mutations by using a multiplex allele-specific PCR method.

Mitochondrial 12S rRNA A1555G and C1494T mutations are the major contributors to hearing loss. As patients with these mutations are sensitive to aminoglycosides, mutational screening for 12S rRNA is therefore recommended before the use of aminoglycosides. Most recently, we developed a novel multiplex allele-specific PCR (MAS-PCR) that can be used for detecting A1555G and C1494T mutations. In the present study, we employed this MAS-PCR to screen the 12S rRNA mutations in 500 deaf patients and 300 controls from 5 community hospitals. After PCR and electrophoresis, two patients with A1555G and one patient with C1494T were identified, this was consistent with Sanger sequence results. We further traced the origin of three Chinese pedigrees. Clinical evaluation revealed variable phenotypes of hearing loss including severity, age at onset and audiometric configuration in these patients. Sequence analysis of the mitochondrial genomes from matrilineal relatives suggested the presence of three evolutionarily conserved mutations: tRNACys T5802C, tRNALys A8343G and tRNAThr G15930A, which may result the failure in tRNAs metabolism and lead to mitochondrial dysfunction that was responsible for deafness. However, the lack of any functional variants in GJB2, GJB3, GJB6 and TRMU suggested that nuclear genes may not play active roles in deafness expression. Hence, aminoglycosides and mitochondrial genetic background may contribute to the clinical expression of A1555G/C1494T-induced deafness. Our data indicated that the MAS-PCR was a fast, convenience method for screening the 12S rRNA mutations, which was useful for early detection and prevention of mitochondrial deafness.

Evidence for gene-smoking interactions for hearing loss and deafness in Japanese American families.

BACKGROUND: This study investigated the relationship between smoking and hearing loss and deafness (HLD) and whether the relationship is modified by genetic variation. Data for these analyses was from the subset of Japanese American families collected as part of the American Diabetes Association Genetics of Non-insulin Dependent Diabetes Mellitus study. Logistic regression with generalized estimating equations assessed the relationship between HLD and smoking. Nonparametric linkage analysis identified genetic regions harboring HLD susceptibility genes and ordered subset analysis was used to identify regions showing evidence for gene-smoking interactions. Genetic variants within these candidate regions were then each tested for interaction with smoking using logistic regression models. RESULTS: After adjusting for age, sex, diabetes status and smoking duration, for each pack of cigarettes smoked per day, risk of HLD increased 4.58 times (odds ratio (OR) = 4.58; 95% Confidence Interval (CI): (1.40,15.03)), and ever smokers were over 5 times more likely than nonsmokers to report HLD (OR = 5.22; 95% CI: (1.24, 22.03)). Suggestive evidence for linkage for HLD was observed in multiple genomic regions (Chromosomes 5p15, 8p23 and 17q21), and additional suggestive regions were identified when considering interactions with smoking status (Chromosomes 7p21, 11q23, 12q32, 15q26, and 20q13) and packs-per-day (Chromosome 8q21). CONCLUSIONS: To our knowledge this was the first report of possible gene-by-smoking interactions in HLD using family data. Additional work, including independent replication, is needed to understand the basis of these findings. HLD are important public health issues and understanding the contributions of genetic and environmental factors may inform public health messages and policies.

Case report: Novel GJB2 variant c.113T>C associated with autosomal recessive non-syndromic hearing loss (ARNSHL) in a Han family.

RATIONALE: Molecular mechanism underlying the autosomal recessive non-syndromic hearing loss (ARNSHL) is still plausible. Pathogenic mutations of the gap junction beta 2 protein (GJB2) are reported to be the primary causes of ARNSHL. PATIENT CONCERNS: A propositus was diagnosed as ARNSHL with bilateral congenital profound hearing loss. DIAGNOSIS: With microarray and target gene sequencing testing methods, a novel GJB2 mutant was found to be associated with ARNSHL in this Han Chinese family. INTERVENTIONS/OUTCOMES: Based on the finding in this research, prenatal screening of GJB2 mutation and genetic counseling are recommended to this family for their next pregnancy. Our interventions allow the family to plan informatively. LESSONS: In this family, we discovered 2 heterozygous carriers of c.113T>C variation in the GJB2 gene. The propositus, who had profound hearing loss, had inherited the c.113T>C variation from his normal mother and the c.235delC from his father.

The spectrum of GJB2 gene mutations in Algerian families with nonsyndromic hearing loss from Sahara and Kabylie regions.

INTRODUCTION: DFNB1, caused by mutations of GJB2 or GJB6, is the most prevalent genetic form of nonsyndromic (i.e., isolated) congenital deafness in countries located around the Mediterranean Sea. Because some mutations are restricted to specific ethnic-geographic groups, we studied the prevalence and spectrum of GJB2/GJB6 mutations in deaf patients originating from two different Algerian regions, Kabylie and Sahara. PATIENTS AND METHODS: Among 91 reportedly unrelated Algerian patients affected by prelingual deafness, 80 patients (41 from Kabylie and 39 from Sahara) were diagnosed with isolated deafness. All had profound deafness, except one patient with mild deafness. They were screened for the presence of GJB2 mutations by direct sequencing of the single coding exon of GJB2. Patients without mutations were then screened for the presence of the most frequent two deletions of GJB6: del(GJB6-D13S1854) and del(GJB6-D13S1830). RESULTS: Causative mutations were found in 13 and 8 patients from Kabylie and Sahara, respectively, accounting for more than a quarter of the cohort. The c.35delG, p.Gly12Valfs*2 mutation remains the most important mutation both in Kabylie (10 patients) and Sahara (7 patients). All detected patients were homozygous for this mutation. In addition, two other mutations (c.139G > T, p.Glu47* and c.167delT, p.Leu56Argfs*26) were found homozygous in one family each, and two patients were compound heterozygotes for (c.35delG p.Gly12Valfs*2/c.139G > T, p.Glu47*). No deletion of GJB6 was detected. CONCLUSION: We confirm that mutations in GJB2, mainly c.35delG, are one of the most prevalent causes of nonsyndromic congenital deafness in Algeria, whereas the del (GJB6-D13S1854) and del (GJB6-D13S1830) deletions of GJB6 contribute little, if any. Further investigation is needed to identify the cause of deafness in other patients without diagnostic.

Deafness and Ethnicity: Taking Identity, Language, and Culture Into Account.

Deaf education professionals are regularly challenged by the linguistic and cultural diversity of deaf youth. The present article focuses on how young deaf people residing in France who are migrants or the children of migrants define themselves, and how parents and professionals perceive their linguistic and cultural diversity. The theoretical frameworks of interactionism and intersectionality were both used to analyze deafness and ethnicity. Qualitative data were collected in French schools through interviews with different members of the school community: students, parents, and professionals. The results show that deafness prevails over ethnicity in regard to self-identification, even if linguistic and cultural diversity can also be taken into account in an inclusive education.

Frequency of GJB2 mutations in patients with nonsyndromic hearing loss from an ethnically characterized Brazilian population / Frequência de mutações de GJB2 em pacientes com perda auditiva não sindrômica em uma população brasileira etnicamente caracterizada

Abstract Introduction: In different parts of the world, mutations in the GJB2 gene are associated with nonsyndromic hearing loss, and the homozygous 35delG mutation (p.Gly12Valfs*2) is a major cause of hereditary hearing loss. However, the 35delG mutation is not equally prevalent across ethnicities, making it important to study other mutations, especially in multiethnic countries such as Brazil. Objective: This study aimed to identify different mutations in the GJB2 gene in patients with severe to profound nonsyndromic sensorineural hearing loss of putative genetic origin, and who were negative or heterozygote for the 35delG mutation. Methods: Observational study that analyzed 100 ethnically characterized Brazilian patients with nonsyndromic severe to profound sensorineural hearing loss, who were negative or heterozygote for the 35delG mutation. GJB2 mutations were detected by DNA-based sequencing in this population. Participants' ethnicities were identified as Latin European, Non-Latin European, Jewish, Native, Turkish, Afro-American, Asian and Others. Results: Sixteen participants were heterozygote for the 35delG mutation; 14 participants, including three 35delG heterozygote's, had nine different alterations in the GJB2 gene. One variant, p.Ser199Glnfs*9, detected in two participants, was previously unreported. Three variants were pathogenic (p.Trp172*, p.Val167Met, and p.Arg75Trp), two were non-pathogenic (p.Val27Ile and p.Ile196Thr), and three variants were indeterminate (p.Met34Thr, p.Arg127Leu, and p.Lys168Arg). Three cases of compound heterozygosity were detected: p.[(Gly12Valfs*2)];[(Trp172*)], p.[(Gly12Valfs*2)](;)[(Met34Thr)], and p.[(Gly12Valfs*2)(;)[(Ser199Glnfs*9)]). Conclusion: This study detected previously unclassified variants and one case of previously unreported compound heterozygosity.

Resumo Introdução: Em diferentes partes do mundo, mutações do gene GJB2 estão associadas a perda auditiva não sindrômica e a mutação homozigótica 35delG (p.Gly12Valfs*2) é uma das principais causas de perda auditiva hereditária. No entanto, a mutação 35delG não é igualmente prevalente em todas as etnias, faz com que seja importante estudar outras mutações, especialmente em países multiétnicos, como o Brasil. Objetivo: Identificar diferentes mutações no gene GJB2 em pacientes com perda auditiva neurossensorial grave ou profunda não sindrômica de origem genética putativa e negativos ou heterozigotos para a mutação 35delG. Método: Estudo observacional que analisou 100 pacientes brasileiros caracterizados etnicamente, com perda auditiva neurossensorial grave ou profunda não sindrômica, negativos ou heterozigotos para a mutação 35delG. As mutações de GJB2 foram detectadas por sequenciamento baseado no DNA nessa população. As etnias dos participantes foram identificadas como latino-europeia, não latino-europeia, judaica, nativa, turca, negra, asiática e outras. Resultados: Dezesseis participantes eram heterozigotos para a mutação 35delG e 14, incluindo três heterozigotos para 35delG, apresentaram nove alterações no gene GJB2. Uma variante, p.Ser199Glnfs*9, detectada em dois participantes, não havia sido relatada anteriormente. Três variantes eram patogênicas (p.Trp172*, p.Val167Met, e p.Arg75Trp), duas não patogênicas (p.Val27Ile e p.Ile196Thr) e três indeterminadas (p.Met34Thr, p.Arg127Leu, e p.Lys168Arg). Três casos de heterozigosidade composta foram detectados: p.[(Gly12Valfs*2)];[(Trp172*)], p.[(Gly12Valfs*2)](;)[(Met34Thr)], e p.[(Gly12Valfs*2)(;)[(Ser199Glnfs*9)]). Conclusão: Este estudo detectou variantes não classificadas anteriormente e um caso de heterozigosidade composta ainda não relatada.

Frequency of GJB2 mutations in patients with nonsyndromic hearing loss from an ethnically characterized Brazilian population.

INTRODUCTION: In different parts of the world, mutations in the GJB2 gene are associated with nonsyndromic hearing loss, and the homozygous 35delG mutation (p.Gly12Valfs*2) is a major cause of hereditary hearing loss. However, the 35delG mutation is not equally prevalent across ethnicities, making it important to study other mutations, especially in multiethnic countries such as Brazil. OBJECTIVE: This study aimed to identify different mutations in the GJB2 gene in patients with severe to profound nonsyndromic sensorineural hearing loss of putative genetic origin, and who were negative or heterozygote for the 35delG mutation. METHODS: Observational study that analyzed 100 ethnically characterized Brazilian patients with nonsyndromic severe to profound sensorineural hearing loss, who were negative or heterozygote for the 35delG mutation. GJB2 mutations were detected by DNA-based sequencing in this population. Participants' ethnicities were identified as Latin European, Non-Latin European, Jewish, Native, Turkish, Afro-American, Asian and Others. RESULTS: Sixteen participants were heterozygote for the 35delG mutation; 14 participants, including three 35delG heterozygote's, had nine different alterations in the GJB2 gene. One variant, p.Ser199Glnfs*9, detected in two participants, was previously unreported. Three variants were pathogenic (p.Trp172*, p.Val167Met, and p.Arg75Trp), two were non-pathogenic (p.Val27Ile and p.Ile196Thr), and three variants were indeterminate (p.Met34Thr, p.Arg127Leu, and p.Lys168Arg). Three cases of compound heterozygosity were detected: p.[(Gly12Valfs*2)];[(Trp172*)], p.[(Gly12Valfs*2)](;)[(Met34Thr)], and p.[(Gly12Valfs*2)(;)[(Ser199Glnfs*9)]). CONCLUSION: This study detected previously unclassified variants and one case of previously unreported compound heterozygosity.

The Prevalence of Ultrarapid Metabolizers of Codeine in a Diverse Urban Population.

OBJECTIVE: To examine the prevalence of ultrarapid metabolizers of codeine among children in an ethnically diverse urban community. STUDY DESIGN: Cross-sectional study. SETTING: A tertiary care academic children's hospital in the Bronx, New York. SUBJECTS AND METHODS: In total, 256 children with nonsyndromic congenital sensorineural hearing loss were analyzed. DNA was assessed for 63 previously described single-nucleotide polymorphisms (SNPs) and copy number variants (CNVs) known to alter the function and expression of the CYP2D6 gene primarily responsible for codeine metabolism. The rate of CYP2D6 metabolism was predicted based on participants' haplotype. RESULTS: Ethnic distribution in the study subjects paralleled recent local census data, with the largest portion (115 children, 45.8%) identified as Hispanic or Latino. A total of 154 children (80.6%) had a haplotype that corresponds to extensive codeine metabolism, 18 children (9.42%) were identified as ultrarapid metabolizers (UMs), and 16 children (8.37%) were intermediate metabolizers. Only 3 children in our cohort (1.57%) were poor metabolizers. Patients identifying as Caucasian or Hispanic had an elevated incidence of UMs (11.3% and 11.2%, respectively) with extensive variability within subpopulations. CONCLUSIONS: The clinically significant rate of ultrarapid metabolizers reinforces safety concerns regarding the use of codeine and related opiates. A patient-targeted approach using pharmacogenomics may mitigate adverse effects by individualizing the selection and dosing of these analgesics.

Predicament and Pilgrimage: Hearing Families of Deaf Children in Mexico City.

In this article, I trace the most salient features of Mexican families' complex journeys as they coped with the "predicament" of childhood deafness. Framing support seeking through the theoretical lens of pilgrimage brings into focus family introspection and captures their tenacity while facing culture-specific obstacles. Ultimately, families realized their quests were not about "fixing" their children's hearing, but finding more reliable communication in sign language. Pilgrimage, as a metaphor for the journeys described by participants, helps us understand families' realizations that the biomedical options most commonly available in Mexico City were of limited efficacy, and reveals collective desire for alternatives to these options.

Service Providers' Perspective on the Education of Students Who Are Deaf or Hard of Hearing and English Learners.

The researchers examine the perspectives of service providers involved in educating students who are both deaf or hard of hearing (DHH) and English Learners (EL). Using qualitative phenomenology methodology, the researchers interviewed eight service providers in one school district about their perspectives on the unique challenges and issues related to educating students who are DHH EL. An overarching finding was the uniqueness of each individual student, which was found in the combination of factors, or "influencers of diversity" (Leigh, 2008, p. 25), for each student. The service providers reported that the students had unique communication, academic, and cultural needs beyond what one would expect to see only in EL or only in DHH learners. The results provide insights into service providers' challenges and needs and how they are met in the provision of effective services to DHH EL students.

Genetic Testing of Non-familial Deaf Patients for CIB2 and GJB2 Mutations: Phenotype and Genetic Counselling.

CIB2 and GJB2 genes variants contribute significantly in familial cases of prelingual recessive hearing loss (HL). This study was aimed to determine the CIB2 and GJB2 variants and associated phenotype in 150 non-familial individuals with HL. After getting informed consent, 150 non-familial deaf patients were enrolled and blood samples were obtained for DNA extraction. Pure tone air conduction audiometry was performed. Coding exons of CIB2 and GJB2 genes were Sanger sequenced. A tetra primer ARMS assay was developed for recurrent CIB2 variant. Four bi-allelic GJB2 variants, c.71G>A p.(Trp24*), c.231G>A p.(Trp77*), c.235delC p.(Leu79Cysfs3*) and c.35delG p.(Gly11Leufs24*), were found in nine hearing impaired individuals. We also found four homozygotes and five carriers of c.380G>A p. (Arg127His) variant of controversial clinical significance. CIB2 sequencing revealed single recurrent variant c.272T>C p. (Phe91Ser) segregating with HL in ten individuals. Among our patients, c.71G>A (p.Trp24*) was the most common variant, accounted for 45% of GJB2 variants. Two known GJB2 variants, c.235delC p. (Leu79Cysfs3*) and c.310del14 p. (Lys105Argfs2*), are reported here for the first time in Pakistani population. Our data further support the benign nature of c.380G>A p. (Arg127His) variant. For CIB2, c.272T>C p. (Phe91Ser) is the second common cause of HL among our sporadic cases. Phenotypically, in our patients, individuals homozygous for GJB2 variants had profound HL, whereas CIB2 homozygotes had severe to profound prelingual HL. Our results suggest that GJB2 and CIB2 are common cause of HL in different Pakistani ethnicities.

Simultaneous multi­gene mutation screening using SNPscan in patients from ethnic minorities with nonsyndromic hearing­impairment in Northwest China.

The present study aimed to investigate the molecular etiology of nonsyndromic hearing impairment (HI) in hearing impaired populations of Hui, Tibetan, and Tu ethnicities in northwest China. A total of 283 unrelated subjects with HI who attended special education schools in northwest China were enrolled in the present study. Single-nucleotide polymorphisms (SNPs) in three common deafness­related genes, gap junction protein ß2 (GJB2), solute carrier family 26 member 4 (SLC26A4) and mitochondrially encoded 12S RNA (mtDNA12SrRNA), were detected using a SNPscan technique. GJB2 mutations were detected in 14.89% of Hui patients, 9.37% of Tibetan patients and 11.83% of Tu patients. The most prevalent GJB2 mutation in the Hui and Tu patients was c.235delC. In the Tibetan patients, the c.109G>A SNP exhibited the highest allele frequency. SLC26A4 mutations were detected in 10.64% of Hui patients, 6.25% of Tibetan patients, and 8.6% of Tu patients. The most common SLC26A4 mutation was c.919­2A>Gin the Hui, Tibetan, and Tu patients, and the second most common SLC26A4 mutations in these patients were c.1517T>G, c.1226G>A andc.2168A>G, respectively. The mutation rates ofmtDNA12SrRNA in the Hui, Tibetan, and Tu patients were 1.06, 5.21, and 5.38%, respectively. These findings demonstrate that the mutation spectra of these deafness­related genes are unique amongst these three ethnic groups. This information will be helpful in designing a protocol for genetic testing for deafness and for achieving accurate molecular diagnoses in northwest China.