Heping Dai

Small heat-shock protein 22 mutated in autosomal dominant Charcot-Marie-Tooth disease type 2L

Charcot-Marie-Tooth (CMT) disease is the most common inherited motor and sensory neuropathy. We have previously described a large Chinese CMT family and assigned the locus underlying the disease (CMT2L; OMIM 608673) to chromosome 12q24. Here, we report a novel c.423G→T (Lys141Asn) missense mutation of small heat-shock protein 22-kDa protein 8 (encoded by HSPB8), which is also responsible for distal hereditary motor neuropathy type (dHMN) II. No disease-causing mutations have been identified in another 114 CMT families.

Molecular analysis of hearing loss associated with enlarged vestibular aqueduct in the mainland Chinese: a unique SLC26A4 mutation spectrum.

AbstractIt has been shown that mutations in the SLC26A4 gene are involved in syndromic deafness characterized by congenital sensorineural hearing impairment and goitre (Pendreds syndrome), as well as in congenital isolated deafness (DFNB4), both of which are associated with enlarged vestibular aqueduct (EVA). The prevalence of SLC26A4 mutations in Pendreds syndrome is clearly established in many ethnic groups, but the data from Mainland Chinese patients with deafness and EVA remain poor. In this report, 15 patients from 13 unrelated Chinese families with deafness and EVA were analyzed for SLC26A4 using direct sequencing. A total of 15 pathogenic mutations were observed in 11 unrelated families, 4 of which were novel. One mutation, IVS7-2A>G, was most common, accounting for 22.3% (5/22) of all the mutant alleles, and H723R was infrequent. To date, a total of 23 mutations have been reported among the Chinese, 13 of which were unique. In conclusion, EVA could be a radiological marker for SLC26A4 analysis among Mainland Chinese hearing-loss patients, and the SLC26A4 mutation spectrum in the Chinese was different from other reported populations.

A ZRS duplication causes syndactyly type IV with tibial hypoplasia

A ZRS Duplication Causes Syndactyly Type IV With Tibial Hypoplasia Lingqian Wu,* Desheng Liang, Norio Niikawa, Fen Ma, Miao Sun, Qian Pan, Zhigao Long, Zhongmin Zhou, Koh-ichiro Yoshiura, Hua Wang, Daisuke Sato, Gen Nishimura, Heping Dai, Xue Zhang, and Jiahui Xia National Laboratory of Medical Genetics, Central South University, Changsha, Hunan, China Solution Oriented Research of Science and Technology (SORST), Japan Science and Technology Agency (JST), Kawaguchi, Japan Research Institute of Personalized Health Sciences, Health Sciences University of Hokkaido, Hokkaido, Japan McKusick-Zhang Center for Genetic Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China Department of Human Genetics, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan Women and Children’s Hospital of Hunan Province, Changsha, Hunan, China Department of Radiology, Tokyo Metropolitan Kiyose Children’s Hospital, Tokyo, Japan

A syndactyly type IV locus maps to 7q36

AbstractSyndactyly occurs as an isolated abnormality or a part of a malformation syndrome. Syndactyly types I, II, III and V have been mapped to chromosomal regions 2q34-q36, 2q31-q32, 6q21-q23.2 and 2q31-q32, respectively, whereas syndactyly type IV (SD4) is extremely rare, and its gene localization has not yet been assigned. The SD4 manifests complete syndactyly of all fingers accompanied with polydactyly, and flexion of the fingers gives the hand a cup-shaped appearance. We performed a linkage and haplotype analysis of a Chinese pedigree with autosomal dominant, non-syndromic SD4 using a set of 406 microsatellite markers. The analysis gave the maximum two-point LOD score of 1.613 at recombination fraction of 0.00 and penetrance of 1.00. Thus, the SD4 locus in the family was likely assigned to a 17.39-cM region at a segment between markers D7S3070 and D7S559 at 7q36, although the LOD score obtained was not high enough to conclude the localization. Analysis of three candidate genes, LMBR1, SHH and ZRS, failed to identify any pathogenic mutations. Our gene mapping may give a clue to identify the putative SD4 gene and provide a better understanding of normal human limb development.

A novel fusion suicide gene yeast CDglyTK plays a role in radio-gene therapy of nasopharyngeal carcinoma

To investigate a novel suicide gene for nasopharyngeal carcinoma (NPC) therapy, the yCDglyTK gene was constructed by fusing yeast cytosine deaminase (CD) and herpes simplex type 1 thymidine kinase. The expression of the yCDglyTK gene was detected by RT-PCR and Western blotting, and its bioactivity was demonstrated by an MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay. An animal study was carried out in which BALB/C nude mice bearing yCDglyTK gene-modified tumors were treated with prodrugs and radiation. Our results revealed that the yCDglyTK gene could be expressed in CNE-2 cells in vitro. In MTT analysis, at the transfection rate of 10%, 66% cells were killed. The synergistic effect of CD and TK showed 91% of yCDglyTK-transfected cells were killed with the treatment of 5-fluorocytosine (5-FC) alone, 60% killed with ganciclovir (GCV) alone, and 75% killed with 5-FC and GCV together. In vivo, the tumor volume in all of the four prodrugs and/or radiation-treated groups were significantly different from that in the PBS-controlled group (P<.01); also yCDglyTK+prodrug+radiation group was different from the other three groups (P<.05). Our findings suggested there was a synergistic antitumor effect when combining suicide gene therapy and radiation, and yCDglyTK has potent antitumor efficacy and may be a candidate suicide gene for cancer therapy.

A novel locus for autosomal dominant nonsyndromic hearing loss identified at 5q31.1-32 in a Chinese pedigree

AbstractHearing impairment is an extremely heterogeneous disorder. A total of 35 loci and 17 related genes for autosomal dominant nonsyndromic hearing loss have been identified. In a Chinese pedigree characterized by autosomal dominant inheritance with bilateral, postlingual, progressive, and sensorineural nonsyndromic hearing impairment, the putative disease gene locus was localized to chromosome 5q31.1-32 by a genome-wide scan. Fine mapping indicated that the disease gene was located within an 8.8-cM region between markers D5S2056 and D5S638, with a maximum two-point logarithm of differences (LOD) score of 6.89 (θ = 0) at D5S2017. By the candidate gene approach, mutation screening of the DIAPH1 and POU4F3 genes at 5q31 was performed. No mutation was found, suggesting that this is a novel deafness locus, which has been named DFNA42.

A father and son with mental retardation, a characteristic face, inv(12), and insertion trisomy 12p12.3-p11.2.

A male patient with mental retardation (MR) and mild facial features was shown by high‐resolution G‐banding to have pericentric inversion of chromosome 12 with an unknown segment inserted into the long arm of the inverted chromosome [46,XY,inv(12)(pteru2009→u2009p11.2::q14.1u2009→u2009p11.2::?::q14.1u2009→u2009qter)]. Both the inverted chromosome 12 and clinical manifestations were transmitted to his son. Karyotypes of the propositus parents were normal. Studies with fluorescence in situ hybridization (FISH) in both the propositus and his son revealed that the extra segment was derived from 12p. Further FISH mapping and the genome‐wide copy number detection by GeneChip Mapping 100K Array showed that an 11‐Mb segment of 12p between two BAC clones, RP11‐22H10 and RP11‐977P2, was inserted at one of the reunion points in the long arm of the inv(12) chromosome. Analysis of parent–child transmissions of duplicated alleles using microsatellite markers defined the maternal origin of the chromosomal anomaly in the propositus and suggested a mechanism of its formation through a sister‐chromatid rearrangement (SCR), that is, mismatched pairing and unequal crossover between sister chromatids as well as three break rearrangements including a U type rearrangement. Karyotypes of the propositus and his son were thus inv(12)(pteru2009→u2009p11.22::q14.1u2009→u2009p12.3::q14.1u2009→u2009qter). This is the first report of “pure” proximal 12p‐trisomy including p12.3–p11.22 region.

Mutation analysis of the ATM gene in two Chinese patients with ataxia telangiectasia

Ataxia telangiectasia (A-T) is an autosomal recessive disorder characterized by cerebellar ataxia, telangiectasia, immunodeficiency, elevated alpha-fetoprotein level, chromosomal instability, predisposition to cancer, and radiation sensitivity. Although a lot of mutations in the ATM gene have been described, there is still no report about ATM mutations in Chinese population. Using a molecular approach, we screened for ATM mutations in two patients from two unrelated Chinese families. 100 normal controls were analyzed to exclude possibility of polymorphism. Two novel mutations in the ATM gene were identified. The first one is a novel, homozygous, 1346G>C (Gly449Ala) missense mutation. The second one is a compound heterozygous mutation, which consists of a novel, 610G>T (Gly204Stop) nonsense mutation, combined with a previously reported, 6679C>T (Arg2227Cys) missense mutation. The transversions 1346G>C (Gly449Ala) and 610G>T (Gly204Stop) are not localized either in the conserved PI-3 kinase domain or in the other domains of the ATM protein. The phenotypic features were characterized by progressive cerebellar ataxia, ocular telangiectasia, elevated alpha-fetoprotein level, immunodeficiency (agammaglo-bulinemia and T-cell defect), and rearrangements of chromosomes 7 and 14; brain MRI showed cerebellar atrophy, brain SPECT showed cerebellar regional cerebral blood flow (rCBF) hypoperfusion. To our knowledge, this is the first report of ATM mutations in Mainland China, in which the transversions 1346G>C (Gly449Ala) and 610G>T (Gly204Stop) are two novel, disease-causing mutations.

Expression of reconstructive hFVIII in the hrDNA by using hrDNA targeting vector

Our lab has constructed a new nonviral vector—hrDNA targeting vector(pHrneo). pHrneo is a human derived vector that can target gene into human ribosomal DNA(hrDNA) locus. In this study, we inserted expression cassette of reconstructive hFVIII (hFVIII-BDDAK39) to pHrneo to construct targeting vector: pHrneo-BDDAK39. Through electroporation of pHrneo-BDDAK39 into HT1080 cells, we identified the homologous recombinants by PCR and Southen blotting, and tested the expression of hFVIII-BDDAK39 in the hrDNA locus. The hFVIII-BDDAK39 was successfully targeted into hrDNA locus of HT-1080 by pHrneo-BDDAK39, and the efficiency of site-specific integration was 2.0×10−5. hFVIII-BDDAK39 in hrDNA locus of HT-1080 is found to be able to express efficiently (32±5 ng·106 cells−1 · 24 h−1). Targeting vector pHrneo-BDDAK39 can find use in gene therapy for hemophilia.

Han Chinese population data for ten STR loci in Changsha, China

Whole blood obtained by venipucture was collected in EDTA vacutainer tubes from unrelated individuals residing in Changsha, China. The DNA was extracted by phenol chloroform method (1). PCR amplification was performed using the AmpFlSTR Profiler Plus™ PCR amplification kit (PE-Biosystems, Foster City, CA) following the manufacturers protocol (2). The amplified products were separated and detected using the ABI Prism™ 377 DNA sequencer (PE-Biosystems, Foster City, CA). The data were analyzed using The Promega Software, POWERSTATS.