[Prediction of quality markers of Angong Niuhuang Pills based on LC-MS and pull-down with SPR chips].

Elucidating the quality markers(Q-markers) of traditional Chinese medicines is essential for understanding the mechanisms of action and promoting the rational use of traditional Chinese medicines as well as for developing traditional Chinese medicine-derived drugs. Studies have shown that surface plasmon resonance(SPR) is promising in this field. This study proposed a method based on pull-down with SPR chips to predict the Q-markers of Angong Niuhuang pills(AGNHP). Firstly, 71 main chemical components of AGNHP were analyzed by UPLC-Q-TOF-MS, and then network pharmacology was employed to predict the potential targets of AGNHP against stroke. Secondly, the STAT3 protein chip was constructed, and the extract of AGNHP was recovered by pull-down of the SPR system for STAT3 ligand. The potential active ingredients were collected, enriched, and identified as coptisine, palmatine, epiberberine, berberine, worenine, demethyleneberberine, jatrorrhizine, tetrahydrocoptisine, baicalein, and baicalin methyl ester. Next, the affinity constants of the 10 active ingredients were determined as 44.7, 44, 58.1, 51.3, 39.7, 32.1, 49.2, 69.1, 19.7, and 24.9 µmol·L~(-1), respectively. The molecular docking results showed that the 10 compounds could compete for binding with STAT3. This is the first report that SPR combined with UPLC-Q-TOF-MS is reliable and feasible for determining the active ingredients of AGNHP at the molecular level from complex systems. STAT3 could be used as a potential target for the biological quality evaluation of AGNHP.

ZxAKT1 is essential for K+ uptake and K+ /Na+ homeostasis in the succulent xerophyte Zygophyllum xanthoxylum.

The inward-rectifying K+ channel AKT1 constitutes an important pathway for K+ acquisition in plant roots. In glycophytes, excessive accumulation of Na+ is accompanied by K+ deficiency under salt stress. However, in the succulent xerophyte Zygophyllum xanthoxylum, which exhibits excellent adaptability to adverse environments, K+ concentration remains at a relatively constant level despite increased levels of Na+ under salinity and drought conditions. In this study, the contribution of ZxAKT1 to maintaining K+ and Na+ homeostasis in Z. xanthoxylum was investigated. Expression of ZxAKT1 rescued the K+ -uptake-defective phenotype of yeast strain CY162, suppressed the salt-sensitive phenotype of yeast strain G19, and complemented the low-K+ -sensitive phenotype of Arabidopsis akt1 mutant, indicating that ZxAKT1 functions as an inward-rectifying K+ channel. ZxAKT1 was predominantly expressed in roots, and was induced under high concentrations of either KCl or NaCl. By using RNA interference technique, we found that ZxAKT1-silenced plants exhibited stunted growth compared to wild-type Z. xanthoxylum. Further experiments showed that ZxAKT1-silenced plants exhibited a significant decline in net uptake of K+ and Na+ , resulting in decreased concentrations of K+ and Na+ , as compared to wild-type Z. xanthoxylum grown under 50 mm NaCl. Compared with wild-type, the expression levels of genes encoding several transporters/channels related to K+ /Na+ homeostasis, including ZxSKOR, ZxNHX, ZxSOS1 and ZxHKT1;1, were reduced in various tissues of a ZxAKT1-silenced line. These findings suggest that ZxAKT1 not only plays a crucial role in K+ uptake but also functions in modulating Na+ uptake and transport systems in Z. xanthoxylum, thereby affecting its normal growth.

Application and progress of high-throughput sequencing technologies in the research of hereditary hearing loss.

Hearing loss (HL) is the most common birth defect. Elucidating the genetic basis of hereditary deafness can not only assist diagnosis, provide the basis for genetic counseling and the prevention of deafness, but also bring a deeper understanding of the disease pathogenesis. In the genomic era, high-throughput sequencing technologies, represented by whole genome sequencing (WGS), whole exome sequencing (WES) or target region sequencing, have been widely used in the studies of hereditary HL. Here, we summarize the application and progress of WES and target region sequencing in the research of causative genes and clinical molecular diagnosis of hereditary HL, hoping to be helpful for the development and improvement of clinical genetic diagnosis of deafness in China.

[Simultaneous determination of seven bioactive compounds and pharmacokinetics in rat plasma after oral administration of Yindan Xinnaotong Ruanjiaonang by UPLC-MS/MS].

To estabish ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for simultaneous determination of quercetin(QCT), isorhamnetin(ISR), kaempferol(KMF), ginkgolide A(GA), ginkgolide B(GB), ginkgolide C(GC) and bilobalide(BB) in rat plasma and investigate the pharmacokinetic process of seven compounds after oral administration of Yindan Xinnaotong Ruanjiaonang, The results indicated that all calibrations curves showed good linearity (r≥0.997 1). RSD of intra-day and inter-day precisions were all within 11%. The matrix effects and extraction recovery were in the range of 93.28%-103.6% and 72.43%-95.77% respectively. The peak concentration (Cmax) of QCT, ISR, KMF, GA, GB, GC and BB were (45.02±11.28), (49.90±13.82), (27.85±8.38), (76.31±18.19), (76.54±15.43), (35.35±10.28), (48.70±12.34) µg•L⁻¹, respectively. The peak time (tmax) of seven constituents were (0.33±0.11), (0.50±0.23), (0.33±0.14), (0.75±0.29), (1.0±0.35), (1.5±0.23), (0.75±0.50) h, respectively. UPLC-MS/MS method established in this research was proved to be so rapid and sensitive that it can be applied to the pharmacokinetic study of seven bioactive constituents in Yindan Xinnaotong Ruanjiaonang.

ZxNHX controls Na⁺ and K⁺ homeostasis at the whole-plant level in Zygophyllum xanthoxylum through feedback regulation of the expression of genes involved in their transport.

BACKGROUND AND AIMS: In order to cope with arid environments, the xerohalophyte Zygophyllum xanthoxylum efficiently compartmentalizes Na(+) into vacuoles, mediated by ZxNHX, and maintains stability of K(+) in its leaves. However, the function of ZxNHX in controlling Na(+) and K(+) homeostasis at the whole-plant level remains unclear. In this study, the role of ZxNHX in regulating the expression of genes involved in Na(+) and K(+) transport and spatial distribution was investigated. METHODS: The role of ZxNHX in maintaining Na(+) and K(+) homeostasis in Z. xanthoxylum was studied using post-transcriptional gene silencing via  Agrobacterium-mediated transformation. Transformed plants were grown with or without 50 mm NaCl, and expression levels and physiological parameters were measured. KEY RESULTS: It was found that 50 mm NaCl induced a 620 % increase in transcripts of ZxSOS1 but only an 80 % increase in transcripts of ZxHKT1;1 in roots of wild-type (WT) plants. Consequently, the ability of ZxSOS1 to transport Na(+) exceeded that of ZxHKT1;1, and Na(+) was loaded into the xylem by ZxSOS1 and delivered to the shoots. However, in a ZxNHX-silenced line (L7), the capacity to sequester Na(+) into vacuoles of leaves was weakened, which in turn regulated long-distance Na(+) transport from roots to shoots. In roots of L7, NaCl (50 mm) increased transcripts of ZxSOS1 by only 10 %, whereas transcripts of ZxHKT1;1 increased by 53 %. Thus, in L7, the transport ability of ZxHKT1;1 for Na(+) outweighed that of ZxSOS1. Na(+) was unloaded from the xylem stream, consequently reducing Na(+) accumulation and relative distribution in leaves, but increasing the relative distribution of Na(+) in roots and the net selective transport capacity for K(+) over Na(+) from roots to shoots compared with the WT. Silencing of ZxNHX also triggered a downregulation of  ZxAKT1 and ZxSKOR in roots, resulting in a significant decrease in K(+) accumulation in all the tissues in plants grown in 50 mm NaCl. These changes led to a significant reduction in osmotic adjustment, and thus an inhibition of growth in ZxNHX-silenced lines. CONCLUSIONS: The results suggest that ZxNHX is essential for controlling Na(+), K(+) uptake, long-distance transport and their homeostasis at whole-plant level via feedback regulation of the expression of genes involved in Na(+), K(+) transport. The net result is the maintenance of the characteristic salt accumulation observed in Z. xanthoxylum and the regulation of its normal growth. A model is proposed for the role of ZxNHX in regulating the Na(+) transport system in Z. xanthoxylum under saline conditions.

Hearing loss and PRPS1 mutations: Wide spectrum of phenotypes and potential therapy.

OBJECTIVE: The purpose of this review was to evaluate the current literature on phosphoribosylpyrophosphate synthetase 1 (PRPS1)-related diseases and their consequences on hearing function. DESIGN: A literature search of peer-reviewed, published journal articles was conducted in online bibliographic databases. STUDY SAMPLE: Three databases for medical research were included in this review. RESULTS: Mutations in PRPS1 are associated with a spectrum of non-syndromic to syndromic hearing loss. Hearing loss in male patients with PRPS1 mutations is bilateral, moderate to profound, and can be prelingual or postlingual, progressive or non-progressive. Audiogram shapes associated with PRPS1 deafness are usually residual and flat. Female carriers can have unilateral or bilateral hearing impairment. Gain of function mutations in PRPS1 cause a superactivity of the PRS-I protein whereas the loss-of-function mutations result in X-linked nonsyndromic sensorineural deafness type 2 (DFN2), or in syndromic deafness including Arts syndrome and X-linked Charcot-Marie-Tooth disease-5 (CMTX5). CONCLUSIONS: Lower residual activity in PRS-I leads to a more severe clinical manifestation. Clinical and molecular findings suggest that the four PRPS1 disorders discovered to date belong to the same disease spectrum. Dietary supplementation with S-adenosylmethionine (SAM) appeared to alleviate the symptoms of Arts syndrome patients, suggesting that SAM could compensate for PRS-I deficiency.

[Clinical features and screening of ACVRL1 gene in II hereditary hemorrhagic telangiectasia].

OBJECTIVE: To analyze the clinical features and pathogenic gene of the patients with hereditary hemorrhagic telangiectasia (HHT). METHODS: The clinical features of 3 HHT families were collected. And the patients were diagnosed according to clinical diagnostic analyzed criteria of HHT, the ACVRL1 gene screened and the conservation of mutation protein. RESULTS: Three probands and 1 patient were diagnostic for HHT and 2 patients were suspected. In family I, there was a missense mutation of ACVRL1 gene in c.287A > G on 2 patients, leading to the transferal of amino acids from Asn to Ser at 96(th) place. In family II, there was a missense mutation of c.1271C > T on ACVRL1 in 2 patients, leading to the transfer of amino acids from Pro to Leu at 424(th) place. In family III, there was a deletion mutation of c.147delC on ACVRL1 so as to produce only the former 53 amino acids of ALK1 protein. Through an analysis of multi-species conservation, the mutations were conserved between multiple species. By querying the National Center for Biotechnology Information (NCBI) database, we confirmed that the mutation was not of a single nucleotide polymorphism (SNP). CONCLUSION: The genetic screening of HHT patients may identify their virulence gene. And genetic screening of their offspring is helpful for the early diagnosis and prevention before disease onset.

[Detection of trisomy 21 by quantitative fluorescent PCR in clinical samples undergoing prenatal diagnosis for hereditary hearing loss].

OBJECTIVE: To establish the genetic test technique of trisomy 21 concurrently conducts with prenatal diagnosis for hereditary hearing loss. METHODS: Fifty-four pregnant women who underwent prenatal diagnosis for hearing loss of their fetuses in Chinese People's Liberation Army General Hospital from March 2009 to May 2010 were enrolled in this study. All probands from the deaf families have confirmed the causative mutation for hearing loss in Genetic Testing Center in Chinese People's Liberation Army General Hospital. The mean age of 54 pregnant women is 31 years at pregnancy of 18 - 26 weeks, 5 cases > pregnancy of 23 weeks, 9 cases ≥ 35 years. All subjects did not conduct the serologic tests for trisomy 21 before. Fifteen to twenty ml amniotic fluid was drawn from 49 cases at pregnancy of 18 - 23 weeks and 5 cases > pregnancy of 23 weeks. One to two ml umbilical blood was drawn from 5 cases > pregnancy of 23 weeks. For 9 cases ≥ 35 years, amniotic fluid cell culture and karyotyping analysis were conducted concurrently. A multiple quantitative fluorescent (QF) PCR and six microsatellite markers were applied to diagnosis trisomy 21. The samples with peaks of 1:1:1 or 2:1 at two microsatellite markers can be diagnosed as trisomy 21. RESULTS: (1) Fifty-four fetuses were successfully conducted prenatal genetic diagnosis for hearing loss (included GJB2 and SLC26A4). Ten fetuses copied the exactly same genotypes as the probands. The other 44 cases fetuses did not copy the same genotypes as the probands and won't develop hearing loss. The hearing test showed normal hearing for the neonates. (2) All the 54 fetuses were excluded of trisomy 21 by QF-PCR and were verified after birth. Five fetuses with advanced maternal age were performed karyotyping analysis and showed normal. The diagnostic results of QF-PCR can be obtained in 1-3 days without misdiagnosed. CONCLUSIONS: QF-PCR is an efficient, rapid and accurate technique for detection of trisomy 21 without increasing sample amount. It can be used for fetuses who were undertaken hearing loss gene test or other prenatal gene test.

ZxNHX1 indirectly participates in controlling K+ homeostasis in the xerophyte Zygophyllum xanthoxylum.

The succulent xerophyte Zygophyllum xanthoxylum (Bunge) Engl. can absorb Na+ from the soil as an osmoticum in order to resist osmotic stress. The tonoplast Na+/H+ antiporter ZxNHX1 is essential for maintaining the salt-accumulation characteristics of Z. xanthoxylum by compartmentalizing Na+ into vacuoles. Previous results revealed that the silencing of ZxNHX1 greatly decreased Na+ accumulation in Z. xanthoxylum under 50 mM NaCl due to the weakened compartmentalisation; in addition, K+ concentration also significantly reduced in ZxNHX1-RNAi lines. Yet, whether the reduction of K+ concentration was directly triggered by the silencing of ZxNHX1 remains unclear. In this study, the growth parameters and expression levels of ZxSOS1, ZxHKT1;1, ZxAKT1 and ZxSKOR were measured in wild-type and ZxNHX1-RNAi lines under control or -0.5 MPa osmotic stress. The results showed that the silencing of ZxNHX1 inhibited the plant growth, decreased Na+ concentration in leaves, reduced the transcript abundance of ZxSOS1 and dramatically increased that of ZxHKT1;1 in roots of Z. xanthoxylum under osmotic stress; whereas tissue K+ concentrations and the expression level of ZxSKOR displayed no significant variations, and the expression of ZxAKT1 were significantly reduced in ZxNHX1-RNAi lines under osmotic stress, compared with the wild type. These results suggest that in Z. xanthoxylum, ZxNHX1 can maintain the normal growth by compartmentalizing Na+ into vacuoles, and regulate the spatial distribution of Na+ indirectly by affecting the expressions of ZxSOS1 and ZxHKT1;1. Moreover, the silencing of ZxNHX1 is not the main reason that led to the reduction of K+ concentration in ZxNHX1-RNAi lines under 50 mM NaCl, and ZxNHX1 might be indirectly involved in regulating K+ homeostasis.

[Development of multiple quantitative fluorescent PCR for rapid diagnosis of common aneuploidy and it's clinical application].

In this study we have established a technique of multiple quantitative fluorescent polymerase chain reaction (QF-PCR) for prenatal diagnosis of common chromosomal abnormality using multiple short tandem repeat markers (STR-marker) on chromosomes 21 and 18 with the DNA samples from 20 cases of Down's syndrome, 3 cases of trisomy 18 and 40 cases normal controls. The technique established was applied in prenatal diagnosis in 165 clinical cases and 4 cases of newborn infants with digestive tract obstruction. The result this technique was compared with the results of karyotyping. Four cases of trisomy 21 and 1 case of trisomy 18 were identified among 169 samples, which was completely concordant with the results of karyotyping. All clinical samples were diagnosed in 1-3 days without misdiagnosis and missed diagnosis. Five cases were diagnosed by QF-PCR only due to the failure of karyotyping. Twenty-two cases of fetuses with structure malformation indicated by B-ultrasonography were subjected to karyotyping. One case of 45, X and 1 case of 47, XXY were identified. In conclusion, QF-PCR technique is rapid and accurate for the detection of trisomy 21 and trisomy 18. It is suitable for prenatal diagnosis of common chromosomal abnormality for pregnant women with advanced ages who were identified as having a high risk by serum screening. QF-PCR technique combined with karyotyping can provide better service for clinical demanding of prenatal diagnosis.

[Study on the association between IL-2R and IL-7R gene polymorphism and idiopathic demyelinating optic neuritis].

OBJECTIVE: To analyze the relationship between the gene polymorphism of IL-2R (rs2104286) and IL-7R (rs6897932) and the susceptibility to idiopathic demyelinating optic neuritis (IDON). METHODS: A case-control study was performed in 72 IDON patients and 81 healthy individuals as the control group. DNA was extracted from peripheral blood leukocytes. PCR was used to amplify the aim genes; the SNP of IL-2R were analyzed by restriction fragment length polymorphism (RFLP) assay and the SNP of IL-7R were analyzed by gene sequencing. The χ2 test was used to compare genotype and allele frequencies between the IDON and control populations. Odds ratio (OR) was calculated using the approximation of Woolf for the 95% confidence interval (CI). RESULTS: No significant difference of genotype (χ2=0.410, P=0.815) and allele frequency(χ2=0.413, P=0.520) of IL-2R gene existed in IDON group(AA:54/AG:15/GG:3;A:123/G:21) as compared with the control group (AA:57/AG:20/GG:4;A:134/G:28). No significant difference of genotype frequency (χ2=3.787, P=0.150) of IL-7R existed in IDON group (CC:56/CT:13/TT:3) as compared with the control group (CC:52/CT:21/TT:8). However, there was a significant difference in IL-7R allele (C/T) between IDON group (C:125/T:19) and the controls (C:125/T:37) (χ2=4.743, P=0.029), OR=1.95 (95%CI: 1.07-3.55). CONCLUSIONS: There is no significant difference in IL-2R rs2104286 polymorphism between IDON group and the controls; the frequencies of IL-7R rs6897932 C allele in IDON group was significantly greater than that of the controls. Polymorphism of IL-7R gene (rs6897932) may contribute to the risk of IDON.

The genetic bases for non-syndromic hearing loss among Chinese.

Deafness is an etiologically heterogeneous trait with many known genetic, environmental causes or a combination thereof. The identification of more than 120 independent genes for deafness has provided profound new insights into the pathophysiology of hearing. However, recent findings indicate that a large proportion of both syndromic and non-syndromic forms of deafness in the Chinese population are caused by defects in a small number of genes. Studies of the genetic epidemiology and molecular genetic features revealed that there is a clear relevance of genes causing deafness in Chinese deaf patients as well as a unique spectrum of common and rare deafness gene mutations in the Chinese population. This review is focused on the genetic aspects of non-syndromic and mitochondrial deafness, in which unique molecular genetic features of hearing impairment have been identified in the Chinese population. The current China population is approximately 1.3 billion. It is estimated that 30,000 infants are born with congenital sensorineural hearing loss each year. Better understanding of the genetic causes of deafness in the Chinese population is important for accurate genetics counseling and early diagnosis for timely intervention and treatment options.

[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.

[Study on the chemical constituents from Clematis brevicaudata].

OBJECTIVE: To study the chemical constituents from Clematis brevicaudata. METHODS: The compounds were isolated by column chromatography and their structures were elucidated through spectroscopic analysis (NMR). RESULTS: Eight compounds were isolated and identified as: palmitic acid (1), 1-docosanol (2), pentacosanoic acid-2', 3'-dihydroxypropyl ester (3), beta-sitosterol (4), daucosterol (5), a mixture of the trans-p-coumarate of the n-alkanols (6), 3,4-dihydroxy-trans coumatate ethyl ester (7), syringaresinol-O-D-glucopyranoside (8). CONCLUSION: All these compounds are obtained from Clematis brevicaudata for the first time.

[Mutation screening of MITF gene in patients with Waardenburg syndrome type 2].

Warrgenburg syndrome type 2 (WS2) is the most common autosomal dominantly-inherited syndrome with hearing loss. MITF (microphthalmia associated transcription factor)is a basic-helix-loop-helix-luecine zipper (bHLHZip) factor which regulates expression of tyrosinase, and is involved in melanocyte differentiation. Mutations in MITF associated with WS2 have been identified in some but not all affected families. Here, we report a three-generation Chinese family with a point mutation in the MITF gene causing WS2. The proband exhibits congenital severe sensorineural hearing loss, heterochromia iridis and facial freckles. One of family members manifests sensorineural deafness, and the other patients show premature greying or/and freckles. This mutation, heterozygous deletion c.639delA, creates a stop codon in exon 7 and is predicted to result in a truncated protein lacking normal interaction with its target DNA motif. This mutation is a novel mutation and the third case identified in exon 7 of MITF in WS2. Though there is only one base pair distance between this novel mutation and the other two documented cases and similar amino acids change, significant difference is seen in clinical phenotype, which suggests genetic background may play an important role.

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.

[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.

[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.

[The mutation R672H in SCN4A gene exists in Chinese patients with hypokalaemic periodic paralysis].

OBJECTIVE: Mutation screening was performed on two Chinese families with HOKPP to locat the corresponding mutations and to specify the clinical features associated with the mutation. METHODS: Target-exon PCR and direct sequencing were used to screen mutation in the CACNA1S and SCN4A gene of all numbers of the two families. The clinical features of patients were summary. RESULTS: A heterozygous point mutation 2015G-->A causing R672H in the SCN4A was found in five patients and five normal relatives of the two families. Features of R672H mutation are incomplete penetrance, especially non-penetrance of phenotype in women and potassium is effective, but acetazolamide is not. CONCLUSION: The SCN4A R672H mutation exists in the Chinese family with HOKPP.

[Large-scale screening of mtDNA A1555G mutation in China and its significance in prevention of aminoglycoside antibiotic induced deafness].

OBJECTIVE: To explore the necessity of large-scale screening of mtDNA A1555G mutation in prevention of aminoglycoside antibiotic induced deafness (AAID) and to develop a feasible method to prevent AAID. METHODS: A total of 1836 patients with non-syndromic hearing impairment (NSHI), 1352 students of schools for deaf-mutes in 11 provinces and municipality in China, 413 out-patients, and 71 persons from the families with maternal relatives suffering from AAID, underwent questionnaire survey and/or PCR for A-to-G mutation at nucleotide 1555 of the mitochondrial genome. RESULTS: Sixty three patients with mtDNA A1555G mutation were found among the 1836 NSHI patients. Fifty-two maternal pedigrees were identified. 536 cases with normal hearing from these pedigrees were informed to avoid using aminoglycoside antibiotics (AmAn). CONCLUSION: Large-scale screening of mtDNA A1555G mutation and relevant health education to avoid use of AmAn are effective to prevent ototoxicity in the A1555G carriers and their maternal relatives.