Induction and Regulation of the Immunoproteasome Subunit ß5i (PSMB8) in Laryngeal and Hypopharyngeal Carcinoma Cells.

BACKGROUND The ubiquitin-proteasome pathway (UPP) is closely associated with the occurrence and progression of cancer, and the 5i immunoproteasome subunit is an important antitumor target in UPP. This study aimed to characterize the regulation of the immunoproteasome subunit ß5i (PSMB8) in JHU-011 laryngeal carcinoma cells and FaDu hypopharyngeal carcinoma cells to explore a new target for the treatment of laryngeal and hypopharyngeal carcinomas. MATERIAL AND METHODS JHU-011 and FaDu cells were used as effector cells in this study. By means of 6°Co γ-irradiation, the construction of stable cell lines of the silenced proto-oncogene c-Abl, and the addition of exogenous tyrosine kinase inhibitor (TKI) and activator, the transcription and protein expression levels of PSMB8 and its alternatively spliced isoforms in both cell lines were detected by real-time fluorescence quantitative polymerase chain reaction (RT-PCR) and Western blot. RESULTS Ionizing radiation upregulated the transcription level of the alternatively spliced isoform of PSMB8, E2, in both cell lines, thereby upregulating the mRNA and protein levels of PSMB8. The silencing of the proto-oncogene c-Abl and the activation and inhibition of its kinetic kinase product can affect the transcription and protein levels of PSMB8. CONCLUSIONS Ionizing radiation can significantly upregulate the mRNA and protein levels of PSMB8, which happens through the upregulation of its splicing isoform E2. The proto-oncogene c-Abl and its kinetic kinase protein product can regulate the transcription and protein expression levels of PSMB8 and its alternatively spliced isoforms.

The Advances in Hearing Rehabilitation and Cochlear Implants in China.

Hearing loss (HL) is a common sensory impairment in humans, with significant economic and social impacts. With nearly 20% of the world's population, China has focused on economic development and health awareness to improve the care for its hearing-impaired population. Recently, the Chinese government has initiated national programs such as the China Disabled Persons Federation to fund prevention, treatment, and rehabilitation of hearing impairment. Newborn hearing screening and auditory rehabilitation programs in China have expanded exponentially with government support. While facing many challenges and overcoming obstacles, cochlear implantation (CI) programs in China have also experienced considerable growth. This review discusses the implementation of CI programs for HL in China and presents current HL data including epidemiology, newborn hearing screening, and determination of genetic etiologies. Sharing the experience in Chinese auditory rehabilitation and CI programs will shine a light on the developmental pathway of healthcare infrastructure to meet emerging needs of the hearing-impaired population in other developing countries.

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.

Induction of the chick columella and its integration with the inner ear.

BACKGROUND: The auditory complex of the chick, like that of humans, is made of intimate and highly ordered connections between the inner ear, the middle ear, and the outer ear. Unlike mammals, the middle ear of chick has only one ossicle, known as the columella. The independent lineages of the two suggest that some mechanism must exist that ensures the connectivity between the inner ear and the columella; however, the basis of integration is not known. RESULTS: Using quail-chick chimeras, we demonstrate that columella development depends on signaling interactions. Specifically, both pharyngeal endoderm and cranial paraxial mesoderm can alter the morphology of the columella. Only a discrete region of pharyngeal endoderm exerts this patterning activity, and this region is specified by the overlying paraxial mesoderm. CONCLUSIONS: Paraxial mesoderm is also used in the induction of the inner ear, thus we propose that this overlapping source of signalling cues in both middle and inner ear development may underlie the integration of these structures.

Identification of SLC26A4 c.919-2A>G compound heterozygosity in hearing-impaired patients to improve genetic counseling.

BACKGROUND: Mutations in the SLC26A4 gene, which encodes the anion transporter, pendrin, are a major cause of autosomal recessive non-syndromic hearing loss (NSHL) in some Asian populations. SLC26A4 c.919-2A>G (IVS7-2A>G) is the most common mutation in East Asian deaf populations. To provide a basis for improving the clinical diagnosis of deaf patients, we evaluated 80 patients with the SLC26A4 c.919-2A>G monoallelic mutation from 1065 hearing-impaired subjects and reported the occurrence of a second mutant allele in these patients. METHODS: The occurrence of a second mutant allele in these 80 patients with a single c.919-2A>G mutation was investigated. Mutation screening was performed by bidirectional sequencing in SLC26A4 exons 2 to 6 and 9 to 21. RESULTS: We found that 47/80 patients carried another SLC26A4 c.919-2A>G compound mutation. The five most common mutations were: p.H723R, p.T410M, 15+5G>A (c.1705+5G>A), p.L676Q and p.N392Y. We found a Chinese-specific SLC26A4 mutation spectrum and an associated SLC26A4 contribution to deafness. CONCLUSION: Our study illustrates that mutation analysis of other SLC26A4 exons should be undertaken in deaf patients with a single heterozygous SLC26A4 mutation. Moreover, a model of compound heterozygosity may partially explain the disease phenotype.

[Changes of gamma-amino butyric acid and electrophysiology inferior colliculus after noise exposure in guinea pig].

OBJECTIVE: To explore the changes of inferior collicular (IC) neurons after noise exposure cochlea injury in guinea pig to elucidate the encoding mechanism of pure tones, observe the changes of IC gamma-amino butyric acid (GABA) after cochlear damage by acoustic trauma and understand the possible mechanism of symptoms such as noise-induced tinnitus, hyperacusis and loudness recruitment. METHODS: The responses of IC neurons to pure tone stimuli were observed in guinea pig at Day 1 and Days 11-21 after cochlear damage induced by noise exposure. And the IC neurons of normal guinea pig were assigned as the controls. Reverse transcription-polymerase chain reaction (RT-PCR) was used to measure the concentrations of GABA(A) and GABA(B) receptors. RESULTS: (1) The types of frequency reaction area (FRA) in the experiment group were the same as those in the control group (V-shape 84.8%, W-shape 8.9%, N-shape 6.3%). But the percentages of types were markedly different at Day 1 (V-shape 63.9%, W-shape 18.1%, N-shape, 18.1%) and Days 11-21 (V-shape 84.2%, W-shape 12.3%, N-shape 3.5%) after noise exposure. (2) After noise exposure, there was a marked fault in characteristic frequency (CF) and depth function map corresponding to 4 kHz (noise frequency). The rake ratio of CF and depth linear function map in the experiment group was lower than that of the control group. The control group, Day 1 and Days 11-21 after noise exposure, the rake ratios were 6.6, 5.8, 5.2 respectively. (3) GABA(A)/GABA(B) receptors decreased markedly at Days 1, 11 and 21 post-exposure compared to normal controls. And the values increased gradually with the prolonged time after exposure. The above findings conformed to the changes of electrophysiology of IC. CONCLUSIONS: After acoustic trauma, the responses of IC neurons to pure tone stimuli change with the elongation of time. It may be explained by the changes of IC GABA receptors after noise exposure.

Math1 gene transfer based on the delivery system of quaternized chitosan/Na-carboxymethyl-beta-cyclodextrin nanoparticles.

Mammalian cochlear hair cells don't regenerate naturally after injury, which usually leave permanent hearing loss. Math1 gene is a positive regulator of hair cell differentiation during cochlear development and was proved to be very critical in hair cell regeneration in deaf animals. Generating new cochlear hair cells by forced Math1 expression may be a cure for hearing loss. However, satisfying gene delivering vectors in gene therapy are not available. We combined quaternized chitosan (QCS) with Na-carboxymethyl-beta-cyclodextrin (CM-beta-CD) as novel non-viral vector, which adsorbs pRK5-Math1-EGFP perfectly at the mass ratio of 4:1. In vitro cell transfection can reach a 40% transfect efficiency and relatively low cytotoxity than liposomes. These results suggest that QCS/CM-beta-CD nanoparticle complexes could be a novel non-viral gene carrier in further clinical application.

[Evaluation of deaf-mute patients with sensitive deafness gene screening in Shandong province].

OBJECTIVE: To discuss how to determine the number of samples in epidemiological study about deafness genes and reveal the characteristics of GJB2, SLC26A4 and mitochondrial DNA A1555G mutations in deaf-mute patients in schools for deaf-mutes in Shandong Province. METHODS: A total of 485 subjects were collected from the different schools for deaf-mutes in Shandong province. Amplified target fragments included GJB2 coding sequence, mtDNA12SrRNA and exon 8, 10, 17, 19 of SLC26A4 gene. The amplicons of mtDNA 12S rRNA were subjected to restriction enzyme Alw26I. The amplicons of patients whose enzyme reaction highly indicating A1555G mutation, amplicons of GJB2 and those exons PCR products of SLC26A4 were directly sequenced. RESULTS: The study revealed that 36.29% patients had two mutated alleles (homozygote & compound heterozygote) of GJB2 (24.12%) and SLC26A4 (6.60%) and mtDNA12SrRNA A1555G (5.57%). The 235delC and IVS7-2A > G were still the mutational hot spot in GJB2 and SLC26A4 respectively. CONCLUSION: The method of determining the number of sample is very important in the epidemiological study. There were about 24 thousand deaf-mute patients who were caused by three sensitive deafness genes mutations in Shandong province. Screening the sensitive deafness genes in newborn is imminent.

[Genetic counseling and instruction of marriage for deaf young people: study of 115 cases].

OBJECTIVE: To invesigate the molecular pathogenesis of deafness among the youth by means of genetic testing so as to provide pre-marriage genetic counseling and instruction for the deaf youth. METHODS: 217 deaf young people, 126 males and 91 females, aged 18.9 (16 - 26), from Yunnan and Guizhou provinces, underwent history taking, auditory testing, and collection of peripheral blood samples. Genomic DNA and mitochondrial DNA were extracted to undergo sequence analysis of the entire gene GJB2, common point mutation of SLC26A4 gene, and mutation of mtDNA A1555G. Genetic prediction and marriage instruction were provided to each subject based on these results. RESULTS: Twenty-three of the 117 persons (10.5%), 13 males and 10 females, were mtDNA A1555G mutation carriers and they were instructed that they, their maternal relatives, and the offspring of the female carriers, should they be born, should strictly avoid the administration of amino glycoside antibiotics. Twenty eight of the 115 persons (12.9%), were confirmed to carry homozygous or compound GJB2 mutations, 5 individuals (2.3%) carried heterozygous GJB2 mutation, 19 (8.8%) carried homozygous or compound SLC26A4 mutations, and one (0.5%) carried heterozygous SLC26A4 mutation. The suggestion for them was to avoid getting married with deaf partners caused by the same deaf gene or with individuals carrying mutations in the same deaf gene. Meanwhile, suggestions such as avoiding aggressive exercises and head injury were provided to the deaf young people with SLC26A4 mutations. CONCLUSION: Genetic testing can provide more accurate and useful genetic counseling and instruction to deaf young people for their partner selection and eugenics.

[Molecular etiology of non-syndromic hearing impairment in a Chinese family].

OBJECTIVE: To investigate the molecular etiology of non-syndromic hearing impairment in two patients in a maternal inherited deafness Chinese family. METHODS: Peripheral blood specimens were collected and DNA templates extracted. The complete mitochondrial genomes and GJB2 gene were sequenced in an ABI 3100 Avant sequencer. RESULTS: The proband (III-5) and her elder sister (III-1) were found to carry the mtDNA 12SrRNA C1494T mutation. The GJB2 gene showed no mutations. The proband had the history of using aminoglycosides before hearing loss, and exhibited severe sensorineural hearing impairment; the proband's sister had no history of using aminoglycosides, and showed moderate sensorineural hearing impairment. CONCLUSION: The molecular etiology of each individual patient in a family yaries with individual genetic background.

[Mutation of Gap junction protein beta 2 gene and treatment outcome of cochlear implantation in cochlear implantation recipients].

OBJECTIVE: To investigate the Gap junction protein beta 2 (GJB2) gene mutation in cochlear implantation (CI) recipients and the treatment outcome of CI in the CI recipients with GJB2 gene mutation. METHODS: Peripheral blood samples were collected from 253 CI recipients with autosomal recessive non-syndromic hearing impairment (NSHI), 174 males and 79 females, aged (8 +/- 9) (112 months-52.7 years), and 301 children with normal hearing level as controls. PCR was used to detect the GJB2 mutations. The auditory threshold with CI and speech recognition of the CI recipients with GJB2 mutation were compared with those of the CI recipients without GJB2 mutation (control group). Questionnaire survey, with meaningful auditory integration scale (MAIS), categories of auditory performance (CAP), and speech intelligibility rating (SIR), was used for young infants. RESULTS: Sixty-seven of the 253 CI recipients (26.5%) were found to have GJB2 mutations. One novel mutation, GJB2 235delC/598G > A, was identified. The detection rates of GJB2 mutations in the CI recipients were significantly higher than those among the controls (all P < 0.05). The postoperative outcomes of CI in both the GJB2 gene mutation positive and negative groups were very good, however, without significant differences among these 2 groups (all P > 0.05). CONCLUSION: GJB2 gene mutation is one of the major causes for CI recipients with autosomal recessive NSHI. The treatment outcomes of CI recipients with GJB2 gene mutations under 7 years old are satisfying.

[Visual evoked potentials in adults with migrainous vertigo].

OBJECTIVE: To investigate the visual evoked potentials in adults with migrainous vertigo (MV). METHODS: Totally 113 patients with MV were enrolled from vertigo clinic. Patients received necessary laboratory examinations as well as pattern visual evoked potential (PVEP) testing. RESULTS: Definite MV accounted for 46.9% (53/113) and probable MV accounted for 53.1% (60/113). Among 74 patients who received PVEP, the results were normal in 35 patients (47.3%) and abnormal in 39 patients (52.7%). The abnormal manifestations included lowered N75-P100 amplitude, elongated latency of P100, and lowered N75-P100 amplitude combined with delayed latency of P100. Seven patients with MV had unilateral lowered N75-P100 amplitude and 4 had bilateral abnormal amplitude. Nine patients had unilateral delayed latency of P100 and 11 had bilateral abnormal latency. Four patients had unilateral and 4 had bilateral abnormal N75-P100 amplitude and latency of P100. CONCLUSIONS: MV patients usually have abnormal PVEP. PVEP may become a useful electrophysiological test in the diagnosis of MV.

Satisfactory surgical option for congenital microtia with defects of external auditory meatus (EAM) and middle ear.

CONCLUSIONS: Improved appearance and hearing and increased efficiency are achievable for congenital microbia with defects of external auditory meatus (EAM) and middle ear. First the site of the external auditory meatus (EAM) orifice must be located according to the results of the temporal CT scan, then the auricle can be reconstructed employing the three-stage method. At the third stage, the EAM and middle ear can be reconstructed at the same time. OBJECTIVE: To select the best approach for reconstruction of congenital microtia with defects of the EAM and middle ear. PATIENTS AND METHODS: This study analyzed 498 cases (528 ears) of auricle reconstruction by the three-stage method and 77 cases (91 ears operation/120 ears) of EAM and middle ear reconstruction. RESULTS: For auricular reconstructions, the effects of reconstructed auricles were classified into four grades according to their structure verisimilitude and the bilateral symmetry. The majority of patients/families were satisfied. For 52 ears with normal movement of stapes, reconstructions of EAM and middle ear improved hearing by 15-50 dB, but long-term improvement was not ideal. In bilateral patients, 20 of 24 ears with reconstructed EAMs exhibited relapse of stenosis or atresia. For patients whose EAMs were reconstructed first, scar developed around the orifice and affected the skin flap and later auricle reconstruction, while reconstructing the auricle first sometimes resulted in the location of the EAM orifice deviating from an ideal position.

Nonsense mutations in the PAX3 gene cause Waardenburg syndrome type I in two Chinese patients.

BACKGROUND: Waardenburg syndrome type I (WS1) is an autosomal dominant disorder characterized by sensorineural hearing loss, pigmental abnormalities of the eye, hair and skin, and dystopia canthorum. The gene mainly responsible for WS1 is PAX3 which is involved in melanocytic development and survival. Mutations of PAX3 have been reported in familiar or sporadic patients with WS1 in several populations of the world except Chinese. In order to explore the genetic background of Chinese WS1 patients, a mutation screening of PAX3 gene was carried out in four WS1 pedigrees. METHODS: A questionnaire survey and comprehensive clinical examination were conducted in four Chinese pedigrees of WS1. Genomic DNA from each patient and their family members was extracted and exons of PAX3 were amplified by PCR. PCR fragments were ethanol-purified and sequenced in both directions on an ABI_Prism 3100 DNA sequencer with the BigDye Terminator Cycle Sequencing Ready Reaction Kit. The sequences were obtained and aligned to the wild type sequence of PAX3 with the GeneTool program. RESULTS: Two nonsense PAX3 mutations have been found in the study population. One is heterozygous for a novel nonsense mutation S209X. The other is heterozygous for a previously reported mutation in European population R223X. Both mutations create stop codons leading to truncation of the PAX3 protein. CONCLUSIONS: This is the first demonstration of PAX3 mutations in Chinese WS1 patients and one of the few examples of an identical mutation of PAX3 occurred in different populations.

[The roles of connexin genes in sporadic hearing loss population].

OBJECTIVE: To investigate the roles of connexin genes in Chinese population. METHODS: Peripheral blood samples were collected from 214 patients with hearing loss, 160 with sensorineural hearing loss (66 with prelingual hearing loss and 94 with postlingual hearing loss), 32 with auditory neuropathy, and 22 with enlarged vestibular aqueduct syndrome (EVAS), 110 males and 104 females, all from 14 provinces north of the Yangtze River, all of Han nationality, and 86 normal controls. PCR and sequencing of the PCR products were used to screen 3 connexin genes: GJB2, GJB3, and GJB6. RESULTS: The frequency of connexin gene sequence variant was 73.36% (157/214), higher than that of the controls (60.05%, 42/86). 34 of the 157 patients carried pathogenic mutations (15.89%). The frequency of 235delC deletion was 16.67% among patients with prelingual hearing loss (11/66). Six known polymorphisms and six new mutations were found in these patients. CONCLUSION: The pathogenic mutations of the patients with hearing loss are distributed quite differently between the patients and normal persons. The genetic variants GJB2 235delG and GJB6-Delta (GJB6/D13S1830) were not common. Relevant information is helpful in early diagnosis of hearing loss in Chinese population.

[Prevalence of GJB2 mutations in Uigur and Han ethnic populations with deafness in Xinjiang region of China].

OBJECTIVE: To investigate the prevalence of GJB2 mutations in Uigur and Han ethnic groups in Xinjiang Uigur Autonomous Region, China and to understand the mutation spectrum and frequency of the GJB2 gene in these 2 ethnic groups. METHODS: Questionnaire survey was conducted among 61 Uigur deaf-mute students, 60 Han deaf-mute students, and 98 normal Uigurs and 301 normal Han people as controls. Peripheral blood samples were collected to undergo PCR and sequencing of GJB2 gene. RESULTS: The GJB2 mutation rate of the Uigur deaf-mute students was 19.7%, not significantly different from that of the Han deaf-mute students (17.2%). GJB2 35delG was found only in the Uigur deaf-mutes with a carrier rate of 11.5%, whereas 235delC was identified in both Uigur and Han deaf-mutes. The allelic frequency of 35delG mutation in the Uigur and Han deaf-mutes and the Uigur controls were 7.4% (9/122), 0 (0/128), and 0 (0/196) respectively. The allelic frequencies of the GJB2 235delC mutations in the Uigur and Han deaf-mute students were 5.7% and 9.8%, and the allelic frequencies of 299 - 300delAT were 0.8% and 5.5%. V27I and E114G were the most frequent types of polymorphism. CONCLUSION: There is a rather high mutation rate of GJB2 gene in Xinjiang. The carrier frequency of 35delG of the Uigurs is significantly higher than that of the Han population. 235delC is common in both Uigur and Han people.

[Mutation screening of the COCH gene in familial and sporadic patients with late onset nonsyndromic sensorineural hearing loss among Chinese population].

OBJECTIVE: To investigate the mutational of the coagulation factor C homology (COCH) gene related to autosomal dominant sensorineural nonsyndromic hearing loss (DFNA) with late onset in Chinese population. METHODS: Peripheral blood samples were collected from he members of 26 DFNA families, members of 19 small DFNA families with un recognized inheritance pattern, and 22 sporadic patients with sensorineural nonsyndromic late onset hearing loss, the hearing loss of all of which occurred during the age range 10 - 40, and 100 normal controls. From different parts of China, these subjects underwent questionnaire survey too. Genomic DNA was isolated, COCH mutation was screened by PCR and sequencing, and restriction endonuclease analysis was used to detect the mutation sites of the COCH gene. The conservation in evolution of the target amino acid sequences was analyzed using CluatalX1.82 software. RESULTS: DNA sequencing of coding regions and exon/intron boundaries of COCH 2 - 12 exons identified a heterozygous G-to-A substitution at position 1625 in exon 12 in a large DFNA family, leading to a C542Y substitution, and a heterozygous T-to-C substitution at position 1535 in exon 12 in a small family, leading to a M512T substitutions. Both the residues of Cys542 and M512 were conserved across human, mouse, chicken, and zebrafish. These mutations were not detected in the 100 control subjects. CONCLUSION: The C542Y and the M512T mutations cause hearing loss in Chinese DFNA families.

[Genetic counseling and intervention for families with deaf-mute patients based on genetic testing: analysis of 5 families].

OBJECTIVE: To analyze the molecular genetic mechanisms of pathogenesis of deafness in the families with deaf-mute patients and analyze the strategies of genetic counseling and intervention for these families. METHODS: Peripheral blood samples were collected from the probands with deaf-muteness and their parents of five families and genetic tests were conducted to analyze the GJB2, SLC26A4 (PDS), and mitochondrial DNA (mtDNA) A 1555G genes for the existence of mutation. Families 1-3 had one child with hearing loss each while the parents had normal hearing and the mothers had been pregnant for 6-18 weeks. Both parents of family 4 were deaf-mute, and the wife of family 5 was deaf-mute while her husband had normal hearing. RESULTS: The proband from family 1 was proven to carry compound GJB2 mutations while his parents carried a single GJB2 mutation; prenatal testing showed that the fetus only carried the paternal mutation. The proband from family 2 was proven to carry compound SLC26A4 (PDS) mutations while his parents carried a single SLC26A4 (PDS) mutation; prenatal testing showed that the fetus only carried the paternal mutation. The proband from family 3 and his parents didn't carry any GJB2, SLC26A4 and mtDNA A1555G mutation. Observation showed that the new born babies of these three families all had normal hearing revealed by new born hearing screening and ABR test. The husband from family 4 was homozygous GJB2 235delC while his wife was mtDNA A1555G positive. This couple was advised to strictly avoid the administration of aminoglycoside antibiotics to their future offspring. In family 5, the wife carried compound SLC26A4 (PDS) mutations while her husband carried a single SLC26A4 (PDS) mutation; and they were told about the 50% risk of their offspring's suffering from enlarged vestibular aqueduct syndrome. CONCLUSION: Genetic testing with prenatal testing and relevant intervention for the families with deaf-mute patients can be applied to prevent another deaf-mute member from being born.

[Mutation of GJB2 gene in nonsyndromic hearing impairment patients: analysis of 1190 cases].

OBJECTIVE: To analyze the sequence of GJB2 gene in nonsyndromic hearing impairment (NSHI) patients in China. METHODS: Peripheral blood samples were obtained from 1190 NSHI patients randomly selected from the Deaf and Mute Schools of Beijing, Hebei, Heilongjiang, Jilin, Inner Mongolia, Shanxi, Henan, Hubei, Shaanxi, Gansu, Ningxia, Qinghai, Anhui, Jiangsu, Shanghai, Fujian, Guangdong, and Guangxi, and 301 children with normal hearing level used as controls. Genomic DNA was extracted by extraction kits to undergo polymerase chain reaction and sequencing so as to detect the mutations of GJB2 gene. RESULTS: Sixteen pathogenic mutations of GJB2 gene were found, the most common of which included 235delC, 299-300delAT, and 176del16bp. 250 patients (21.05%) carried definite GJB2 mutations, 245 of which (98%) carried at least one of these 3 common mutations. 222 of the 250 patients (88.80%) carried the mutation 235delC with a detection rate of 18.66%. 62 of the 250 patients (24.80%) carried the mutation 299-300delAT with a detection rate of 5.21%. 19 of the 250 patients (7.60%) carried the mutation 176del16bp with a detection rate of 1.60%. The detection rates of these 3 mutations in the NSHI patients were all significantly higher than those among the controls (all P<0.01). CONCLUSION: The hot spot of GJB2 gene mutations in Chinese NSHI patients is 235delC, followed by 299-300delAT and 176del16bp. These results establish a fundamental basis for drawing a spectrum of GJB2 gene mutation among Chinese population.

A novel mutation of POU3F4 causes congenital profound sensorineural hearing loss in a large Chinese family.

OBJECTIVES/HYPOTHESIS: It is known that approximately 5% of congenital profound hearing impaired cases are inherited in X-linked inheritance. This study aimed at identifying its underlying molecular determinant(s) using a large, five-generation Chinese family with multiple familial cases. STUDY DESIGN: Model-based linkage analysis and positional cloning. METHODS: Model-based genetic linkage analyses were performed with the use of microsatellite polymorphisms to determine disease locus. Mutation screening was performed within the family and unrelated population-based controls to establish molecular evidence as to what caused the specific X-linked inheritance pattern in the family. RESULTS: Clinical investigations of the pedigree demonstrated the extremely high penetrance in the male members but no penetrance in the female members. Linkage analyses mapped the disease to the chromosomal region Xq13.I-Xq23 (maximum X-linkage logarithm of odds score = 3.27). Mutation screening of the candidate genes in the linkage region by direct sequencing revealed a de novo missense substitution (925T>C) in the well-known deaf gene. POU3F4. Direct sequencing on 240 unrelated controls did not detect any mutation. CONCLUSIONS: Multiple analysis approaches demonstrated that these disorders in the family were caused by a founder mutation in the POU3F4 gene. Our findings provided confirmatory molecular evidence to support that development of congenital profound sensorineural hearing loss in the Chinese population results from a novel mutation in the same gene.