Zhigao Long

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.

Sodium chloride modified silica nanoparticles as a non-viral vector with a high efficiency of DNA transfer into cells.

Development of reliable vectors is a major challenge in gene therapy. Previous gene transfer methods using non-viral vectors, such as liposomes or nanoparticles, have resulted in relatively low levels (35 to approximately 50%) of gene expression. We have developed a silicon nanoparticle (SNAP) system, a novel non-viral vector, for DNA transfer into cells. SNAP was synthesized chemically and modified with sodium chloride or sodium iodide. Electronmicroscopy of SNAP and fluorescence microscopy of fluorescence-labeled SNAP revealed that they were generated uniformly, had diameters of 10-100 nm, and showed a better efficiency (about 70%) of DNA transfection into cells as well as protection of DNA against degradation. The microscopy also demonstrated the adhesion of SNAP with HT1080 cell surface and entry of SNAP into the cells without cytotoxicity. Intravenous and/or intra-abdominal administration of the SNAP to mice revealed the accumulation of SNAP in the cells of the brain, liver, spleen, lung, kidney, intestine, prostate and the testis without any pathological cell changes or mortality, suggesting that they passed through the blood-brain, blood-prostate, and blood-testis barriers. These findings indicate that the SNAP generated has good biological characteristics as a potential promising vector for gene transfer, gene therapy and drug delivery.

Mutation analysis of hereditary multiple exostoses in the Chinese

Hereditary multiple exostoses (EXT; MIM 133700) is an autosomal dominant bone disorder. It is genetically heterogeneous with at least three chromosomal loci: EXT1 on 8q24.1, EXT2 on 11p11, and EXT3 on 19p. EXT1 and EXT2, the two genes responsible for EXT1 and EXT2, respectively, have been cloned. Recently, three other members of the EXT gene family, named the EXT-like genes (EXTL: EXTL1, EXTL2, and EXTL3), have been isolated. EXT1, EXT2, and the three EXTLs are homologous with one another. We have identified the intron-exon boundaries of EXTL1 and EXTL3 and analyzed EXT1, EXT2, EXTL1, and EXTL3, in 36 Chinese families with EXT, to identify underlying disease-related mutations in the Chinese population. Of the 36 families, five and 12 family groups have mutations in EXT1 and EXT2, respectively. No disease-related mutation has been found in either EXTL1 or EXTL2, although one polymorphism has been detected in EXTL1. Of the 15 different mutations (three families share a common mutation in EXT2), 12 are novel. Most of the mutations are either frameshift or nonsense mutations (12/15). These mutations lead directly or indirectly to premature stop codons, and the mutations generate truncated proteins. This finding is consistent with the hypothesis that the development of EXT is mainly attributable to loss of gene function. Missense mutations are rare in our families, but these mutations may reflect some functionally crucial regions of these proteins. EXT1 is the most frequent single cause of EXT in the Caucasian population in Europe and North America. It accounts for about 40% of cases of EXT. Our study of 36 EXT Chinese families has found that EXT1 seems much less common in the Chinese population, although the frequency of the EXT2 mutation is similar in the Caucasian and Chinese populations. Our findings suggest a possibly different genetic spectrum of this disease in different populations.

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.

Association analysis of CNTNAP2 polymorphisms with autism in the Chinese Han population.

Objectives Autism is a neurodevelopmental disorder, and genetic factors play an important role in its pathogenesis. Earlier findings suggest the CNTNAP2 as a predisposition locus of autism, but no study has been carried out on the possible association of CNTNAP2 with autism in the Chinese Han population. Methods In this study, three single nucleotide polymorphisms located within the CNTNAP2 were genotyped in 185 Chinese Han autistic families by polymerase chain reaction–restriction fragment length polymorphism analysis, followed by a transmission disequilibrium test. Results The results show that a common noncoding variant (rs10500171) is associated with the increased risk for autism, and haplotype T-A (rs7794745- rs10500171, P=0.011) and haplotype A-T-A (rs10244837- rs7794745- rs10500171, P=0.032) also showed evidence of association. Conclusion The results of family-based association study suggested that the CNTNAP2 is a susceptibility gene of autism in the Chinese Han population.

Analysis of SCA2 and SCA3/MJD repeats in Parkinson's disease in mainland China: genetic, clinical, and positron emission tomography findings.

To investigate the prevalence and clinical feature(s) of Parkinsons disease (PD) patients with expanded (ATXN2 and MJD1) genes of spinocerebellar ataxia type 2 and 3 (SCA2 and SCA3/MJD) in a mainland Chinese population, CAG triplet repeat expansions of (SCA2 and SCA3/MJD) genes (ATXN2 and MJD1) were analyzed in a cohort of 452 PD patients, including 386 sporadic and 66 familial forms. Striatal dopamine transporter was evaluated in two SCA2 and two SCA3/MJD‐positive family members, an idiopathic PD patient and a healthy control using carbon (C11) [11C]‐radiolabeled‐CFT positron emission tomography (PET). We found two patients in one familial PD (FPD) family (1.5%) and two sporadic PD patients (0.5%) with expanded CAG repeats in the ATXN2 locus, four patients in two FPD families (3%) and another three sporadic PD patients (0.8%) in the MJD1 locus. [11C]‐CFT PET in detected members in SCA2 and SCA3/MJD families showed decrements of 11C‐CFT uptake. These findings suggest that a mutation in SCA2 or SCA3/MJD may be one of the genetic causes of PD.

A novel mutation in KCNQ2 gene causes benign familial neonatal convulsions in a Chinese family

Benign familial neonatal convulsions (BFNC) are a rare autosomal dominant inherited epilepsy syndrome. Two voltage-gated potassium channel genes, KCNQ2 on chromosome 20q13.3 and KCNQ3 on chromosome 8q24, have been identified as the genes responsible for benign familial neonatal convulsions. By linkage analysis and mutation analysis of KCNQ2 gene, we found a novel frameshift mutation of KCNQ2 gene, 1931delG, in a large Chinese family with benign familial neonatal convulsions. This mutation is located in the C-terminus of KCNQ2, in codon 644 predicting the replacement of the last 201 amino acids with a stretch of 257 amino acids showing a completely different sequence. An unusual clinical feature of this family is that the seizures of every patient did not remit until 12 to 18 months. This is the first report of KCNQ2 gene mutation in China.

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

Non‐viral ex vivo transduction of human hepatocyte cells to express factor VIII using a human ribosomal DNA‐targeting vector

Summary.  Background: In gene therapy, one of the most important issues is the choice of the vectors. pHrneo is a human‐derived vector previously constructed by our group, which can target a foreign gene into a human ribosomal DNA (hrDNA) locus. Methods and results: In this study, we inserted an expression cassette of reconstructive hFVIII (hFVIII‐BDDAK39) to pHrneo to construct a targeting vector: pHrneo‐BDDAK39. Through electroporation of pHrneo‐BDDAK39 into HL7702 cells (human hepatocyte), we identified the homologous recombinants using polymerase chain reaction, and tested the expression of hFVIII–BDDAK39 located at the hrDNA locus. The hFVIII‐BDDAK39 was successfully targeted into the hrDNA locus of HL7702 by pHrneo‐BDDAK39, and the efficiency of site‐specific integration was 1.1 × 10−5. The hFVIII‐BDDAK39 at the hrDNA locus of HL7702 was found to be able to express efficiently (4.3 ± 0.9 ng 10−6 cells 24 h−1). Conclusion: It has been indicated that the targeting vector pHrneo‐BDDAK39 can be used in gene therapy for hemophilia A.

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.