Zhi-Jun Liu

Identify mutation in amyotrophic lateral sclerosis cases using HaloPlex target enrichment system

To date, at least 18 causative genes have been identified in amyotrophic lateral sclerosis (ALS). Because of the clinical and genetic heterogeneity, molecular diagnosis for ALS faces great challenges. HaloPlex target enrichment system is a new targeted sequencing approach, which can detect already known mutations or candidate genes. We performed this approach to screen 18 causative genes of ALS, including SOD1, SETX, FUS, ANG, TARDBP, ALS2, FIG4, VAPB, OPTN, DAO, VCP, UBQLN2, SPG11, SIGMAR1, DCTN1, SQSTM1, PFN1, and CHMP2B in 8 ALS probands. Using this approach, we got an average of 9.5 synonymous or missense mutations per sample. After validation by Sanger sequencing, we identified 3 documented SOD1 mutations (p.F21C, p.G148D, and p.C147R) and 1 novel DCTN1 p.G59R mutation in 4 probands. The novel DCTN1 mutation appeared to segregate with the disease in the pedigree and was absent in 200 control subjects. The high throughput and efficiency of this approach indicated that it could be applied to diagnose ALS and other inherited diseases with multiple causative genes in clinical practice.

Clusterin variants are not associated with southern Chinese patients with Alzheimer's disease

Recent genome-wide association studies identified clusterin (CLU) to be associated with sporadic Alzheimers disease. To help clarify the relevance of CLU as genetic determinant of AD, we analyzed its association in southern Chinese Han population. This study comprised 499 sporadic Alzheimers disease patients and 592 unrelated age- and sex-matched healthy controls. Four single-nucleotide polymorphisms (rs2279590, rs9331888, rs11136000, and rs1532278) within CLU were selected for genotyping. No positive association was found between the CLU variants and AD. Our study suggests that CLU variants may not be an AD susceptibility factor in southern Chinese Han population.

Intermediate-length polyglutamine in ATXN2 is a possible risk factor among Eastern Chinese patients with amyotrophic lateral sclerosis

An effective treatment for amyotrophic lateral sclerosis (ALS) has not yet been found because the pathogenesis of this fatal disease is not well understood. A number of previous studies demonstrated that intermediate-length polyglutamine repeats within the ataxin-2 gene (ATXN2) might be a risk factor among patients with ALS in Western countries. Here, we aim to determine whether this sequence is a risk factor in Eastern Chinese ALS patients. Therefore, 379 unrelated sporadic ALS patients, 15 unrelated familial ALS patients, and 900 neurologically normal controls were studied. The ATXN2 CAG repeats were amplified using polymerase chain reaction. The products were separated on an 8% polyacrylamide gel and confirmed using Sanger sequencing. The results were evaluated using SPSS 17.0. We found that ATXN2 intermediate-length polyglutamine expansions greater than 24 and 27 repeats were associated with sporadic ALS. Our finding supports the hypothesis that ATXN2 plays an important role in the pathogenesis of ALS.

Association study of ABCA7 and NPC1 polymorphisms with Alzheimer's disease in Chinese Han ethnic population.

Department of Neurology and Institute of Neurology, Huashan Hospital, Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Shanghai Medical College, Fudan University, Shanghai and Department of Neurology, General Hospital of Ningxia Medical University, Ningxia, China Correspondence to Zhi-Ying Wu, MD, PhD, Department of Neurology and Institute of Neurology, Huashan Hospital, Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Shanghai Medical College, Fudan University, 12 Wulumuqi Zhong Road, Shanghai 200040, China Tel/fax: + 86 21 62483421; e-mail: zhiyingwu@fudan.edu.cn

The investigation of genetic and clinical features in Chinese patients with juvenile amyotrophic lateral sclerosis

Juvenile amyotrophic lateral sclerosis (JALS) occurs at an age of onset below 25 years with a heterogeneous disease onset location, variable progression and survival time. To investigate whether an ALS gene profile could resolve any aspects of clinical symptom heterogeneity, we have used targeted sequencing technology in a cohort of 12 JALS patients of Chinese descent. We detected 5 likely pathogenic mutations, 2 in familial probands and 3 in sporadic patients. One was a known TARDBP mutation (p.G348V) and 4 were FUS frameshift mutations including a known p.Gln519Ilefs*9 mutation and 3 novel mutations, p.Gly515Valfs*14, p.Gly486Profs*30, and p.Arg498Alafs*32. Of the 4 FUS mutations, 2 were able to be confirmed as de novo mutations. The TARDBP mutation carrier showed a classic ALS phenotype. All patients with FUS mutations experienced limb weakness at an early age and developed bulbar symptoms during the disease course. FUS mutations have previously been associated with increased JALS disease progression, however, we found a large range 12 to 84 months in disease survival (mean 58.2 months). Our results justify future screening for variants in FUS as it remains the most frequent genetic determinant of early onset, JALS (found in 30% of our patients).

Chinese patients with Huntington's disease initially presenting with spinocerebellar ataxia

Recent studies have described Huntingtons disease (HD) patients with atypical onset of ataxia. Symptoms in these patients can overlap with those of spinocerebellar ataxia (SCA). We retrospectively examined clinical data for 82 HD probands and found 7 had initially been clinically diagnosed as SCA cases. Clinical features in these patients were further investigated and the number of CAG repeats in the huntingtin (HTT) gene was determined by direct sequencing. Genetic screenings for SCAs in the 7 patients were all negative. By contrast, HTT was heterozygous in each patient. The distribution of CAG number in the 7 patients was statistically the same as that in the other 75 patients. Each of 7 HD patients had presented with atypical onset of ataxia. The mean time from onset to HTT genetic testing was 5.6 ± 5.52 years. Three of the patients developed chorea, but the others did not. Our observations confirm the clinical heterogeneity of HD in Han Chinese. Based on these findings, testing for HTT expansions should be considered for clinically diagnosed SCA patients who test negatively in genetic screening of SCA genes.

Common variants at Bin1 are associated with sporadic Alzheimer's disease in the Han Chinese population.

Objectives Recent genome-wide association studies identified bridging integrator 1 (Bin1) to be associated with sporadic Alzheimer’s disease (SAD). To clarify the relevance of Bin1 as a genetic determinant of AD, we analyzed its association in a Han Chinese population from the South East part of mainland China. Methods This study investigated 427 SAD patients and 451 unrelated age-matched and sex-matched healthy controls. Two single nucleotide polymorphisms (rs7561528 and rs744373) adjacent to Bin1 that emerged from previous genome-wide association studies were genotyped using the MassARRAY Analyzer 4 Sequenom platform. Results As expected, the genotype distribution of rs7561528 was significantly different between the SAD group and the controls, with more AG in controls [odds ratio (OR) 0.605, 95% confidence interval (CI) 0.429–0.854, P=0.004], and the difference increased using an additive genetic model (OR 0.593, 95% CI 0.425–0.828, P=0.002). However, we did not observe a difference in the genotype distribution of the rs744373 between the SAD and the control group (OR 1.189, 95% CI 0.809–1.747, P=0.378). Conclusions To the best of our knowledge, our study is the first to confirm the association of the variant rs7561528 adjacent to Bin1 with SAD in a Han Chinese Population.

Associations between apolipoprotein E gene polymorphisms and Alzheimer's disease risk in a large Chinese Han population.

Objective Apolipoprotein E gene (APOE) polymorphisms contributing to the risk of sporadic Alzheimer’s disease (AD) have been identified for decades, but it has not been investigated in large AD samples of Chinese Han population. Methods We performed a cross-sectional study to explore the effect of APOE polymorphisms on sporadic AD in 875 sporadic AD patients and 1,195 cognitive normal controls of Chinese Han. Genotyping of APOE was determined by multiplex amplification refractory mutation system polymerase chain reaction. Results APOE ε3ε4 and ε4ε4 genotypes increased AD risk with dosage effect. The odds ratio (OR) of ε3ε4 was 1.89 and the OR of ε4ε4 was 15.64 compared with that of ε3ε3 in all the subjects. E2ε3 genotype decreased AD risk in all the subjects (OR=0.64), female subgroup (OR=0.57), and late-onset AD subgroup (OR=0.60). However, neither ε2ε2 nor ε2ε4 affected AD risk. About the age at onset (AAO), the influence of APOE ε4 was only exhibited in late-onset AD subgroup, with 1 year lower in ε4-positive ones than negative ones. Further analysis did not show the dosage effect of ε4 pertinent to AAO, though the AAO of ε4ε4 patients decreased by 2 years. E2 did not affect the AAO of AD. Conclusion APOE ε4 is a strong risk factor of AD risk in Chinese Han population, and APOE ε4ε4 genotype might be related to the AAO of late-onset AD.

Clinical features of Chinese patients with Huntington’s disease carrying CAG repeats beyond 60 within HTT gene

Patients with Huntingtons disease (HD) carrying CAG repeats beyond 60 are less frequently seen and clinical features of them have been rarely reported. We identified four unrelated patients carrying CAG repeats beyond 60 (84.0 ± 13.76, ranging from 74 to 104) from 119 Chinese HD patients via direct sequencing. These four were all early onset with a mean age at presenting symptom of 9.8 ± 1.71 years. Paternal transmission was found in three of them and the fourth was apparently sporadic. In addition, they had atypical onset symptoms including epilepsy, intellectual decline, tics and walking instability, which might lead the clinicians to make the wrong diagnosis in the early stage of disease. Our work explores clinical features of Chinese HD patients with an expanded CAG repeat over 60 and may help the clinicians make a correct diagnosis in the early stage of disease.

A variant within FGF1 is associated with Alzheimer's disease in the Han Chinese population

Alzheimers disease (AD) is the most common neurodegenerative disorder characterized by the accumulation of amyloid beta (Aβ) plaques and Tau‐containing neurofibrillary tangles in vulnerable brain areas. The progression of AD is well correlated with hippocampal neuron loss which highly suggests genes associated with neuron survival would be important for AD pathogenesis. According to the recent results of genome‐wide association studies (GWAS) and other reported studies, we selected two single nucleotide polymorphisms (SNPs), rs3765728 within tumor protein p73 (P73), and rs34011 within fibroblast growth factor 1 (FGF1), both genes were related to neuron survival. We analyzed the distribution of rs3765728 and rs34011 in 1,083 Chinese subjects including 429 unrelated sporadic AD patients and 654 unrelated age and gender‐matched control subjects. We found that the genotype distribution of rs34011 was significantly different between AD and control group (χ2 = 9.048, df = 2, P = 0.011). Logistic regression manifested the risk of AD increased in TT genotype carriers in total subjects (Wald = 8.892, df = 1, P = 0.003, odds ratio [OR]:2.009, 95% confidence interval [95%CI]: 1.270–3.178). This effect was also found in APOE ϵ4 carrier group (Wald = 7.844, df = 1, P = 0.005, OR: 4.201, 95%CI: 1.539–11.472), suggesting the rs34011 has a synergetic effect of APOE on AD risk. However, no association was observed between rs3765728 and AD in the Han Chinese population (χ2 = 0.431, df = 2, P = 0.806).