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Introduction: Hereditary ataxias demonstrate a high degree of clinical and genetic heterogeneity. Understanding the genetic etiology of hereditary ataxias is crucial for genetic counseling and clinical management., Methods: The clinical and genetic data of patients with familial or sporadic ataxias who referred to our tertiary medical center were retrospectively analyzed. Probands in this study underwent SCA repeat expansion panel firstly to screen for repeat expansion SCAs; those with negative results had NGS-targeted panels or WES testing to detect conventional mutations., Results: A total of 223 patients were enrolled from 206 families. 5 kinds of coexisting SCA repeat expansions were observed (SCA3/SCA17, SCA3/SCA8, SCA2/SCA8, SCA3/SCA12 and SCA8/SCA12) in 12 patients from 8 families, among which SCA2/SCA8, SCA8/SCA12 and SCA3/SCA12 were reported for the first time. The coexistence of expanded SCA3 with SCA17 alleles was the most common in our study. NGS identified pathogenic/likely pathogenic variants in 12 ataxia causative genes in 13 probands. Spastic paraplegia ataxia was the most common diagnosis. Six novel mutations were detected in five ataxia-related genes., Conclusion: Coexistence may not specific to a certain SCA subtype and the frequency might have been underestimated before. SCA repeat expansion panel should be considered in patients with overlapping SCA features. In addition, our study broadened the conventional mutation spectrum in ataxia-related genes. These results facilitate a better understanding of the genetic basis for hereditary ataxias., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Essential tremor is one of the most common movement disorders. Despite its high prevalence and heritability, the genetic aetiology of essential tremor remains elusive. Up to now, only a few genes/loci have been identified, but these genes have not been replicated in other essential tremor families or cohorts. Here we report a genetic study in a cohort of 197 Chinese pedigrees clinically diagnosed with essential tremor. Using a comprehensive strategy combining linkage analysis, whole-exome sequencing, long-read whole-genome sequencing, repeat-primed polymerase chain reaction and GC-rich polymerase chain reaction, we identified an abnormal GGC repeat expansion in the 5' region of the NOTCH2NLC gene that co-segregated with disease in 11 essential tremor families (5.58%) from our cohort. Clinically, probands that had an abnormal GGC repeat expansion were found to have more severe tremor phenotypes, lower activities of daily living ability. Obvious genetic anticipation was also detected in these 11 essential tremor-positive families. These results indicate that abnormal GGC repeat expansion in the 5' region of NOTCH2NLC gene is associated with essential tremor, and provide strong evidence that essential tremor is a family of diseases with high clinical and genetic heterogeneities., (© The Author(s) (2019). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Rationale: Deep vein thrombosis (DVT) is the formation of a blood clot formed in the deep veins of the lower limbs. Known genetic factors of DVT include deficiencies of antithrombin (AT), protein C, protein S, factor V Leiden mutation, and prothrombin G20210A mutation. Here, a 5-generation Chinese family with inherited DVT was recruited for genetic analysis., Patient Concerns: The patient came to see a doctor because of leg swelling. A color Doppler ultrasound examination showed extensive thrombosis within the deep veins of her left leg. Computed tomography angiography showed a pulmonary embolism in her right lower pulmonary artery., Diagnoses: Type II AT deficiency lead to inherited DVT., Interventions: Whole-exome sequencing and cosegregation analysis were carried for the DVT family., Outcomes: An unreported heterozygous missense variation, c.281T>C, was identified within the SERPINC1 gene. This missense variation of SERPINC1 leads to type II AT deficiency., Lessons: This result further enriched the variation spectrum of the SERPINC1 gene.

Autism spectrum disorder (ASD) is a neurodevelopmental disorder with considerable clinical and genetic heterogeneity. In this study, we identified all classes of genomic variants from whole-genome sequencing (WGS) dataset of 32 Chinese trios with ASD, including de novo mutations, inherited variants, copy number variants (CNVs) and genomic structural variants. A higher mutation rate (Poisson test, P < 2.2 × 10 -16 ) in exonic (1.37 × 10 -8 ) and 3'-UTR regions (1.42 × 10 -8 ) was revealed in comparison with that of whole genome (1.05 × 10 -8 ). Using an integrated model, we identified 87 potentially risk genes (P < 0.01) from 4832 genes harboring various rare deleterious variants, including CHD8 and NRXN2, implying that the disorders may be in favor to multiple-hit. In particular, frequent rare inherited mutations of several microcephaly-associated genes (ASPM, WDR62, and ZNF335) were found in ASD. In chromosomal structure analyses, we found four de novo CNVs and one de novo chromosomal rearrangement event, including a de novo duplication of UBE3A-containing region at 15q11.2-q13.1, which causes Angelman syndrome and microcephaly, and a disrupted TNR due to de novo chromosomal translocation t(1; 5)(q25.1; q33.2). Taken together, our results suggest that abnormalities of centrosomal function and chromatin remodeling of the microcephaly-associated genes may be implicated in pathogenesis of ASD. Adoption of WGS as a new yet efficient technique to illustrate the full genetic spectrum in complex disorders, such as ASD, could provide novel insights into pathogenesis, diagnosis and treatment., (Copyright © 2018. Published by Elsevier Ltd.)

Background: Birt-Hogg-Dubé syndrome is an autosomal dominant hereditary condition caused by mutations in the folliculin-encoding gene FLCN (NM&#95;144997). It is associated with skin lesions such as fibrofolliculoma, acrochordon and trichodiscoma; pulmonary lesions including spontaneous pneumothorax and pulmonary cysts and renal cancer., Methods: Genomic DNA was extracted from peripheral venous blood samples of the propositi and their family members. Genetic analysis was performed by whole exome sequencing and Sanger sequencing aiming at corresponding exons in FLCN gene to explore the genetic mutations of these two families., Results: In this study, we performed genetic analysis by whole exome sequencing and Sanger sequencing aiming at corresponding exons in FLCN gene to explore the genetic mutations in two Chinese families. Patients from family 1 mostly suffered from pneumothorax and pulmonary cysts, several of whom also mentioned skin lesions or kidney lesions. While in family 2, only thoracic lesions were found in the patients, without any other clinical manifestations. Two FLCN mutations have been identified: One is an insertion mutation (c.1579&#95;1580insA/p.R527Xfs on exon 14) previously reported in three Asian families (one mainland family and two Taiwanese families); while the other is a firstly reviewed mutation in Asian population (c.649C > T / p.Gln217X on exon 7) that ever been detected in a French family., Conclusions: Overall, The detection of these two mutations expands the spectrum of FLCN mutations and will provide insight into genetic diagnosis and counseling of Birt-Hogg-Dubé syndrome.

We investigated the association of 4 well-characterized polymorphisms in receptor for the advanced glycation end-product ( RAGE) gene with myocardial infarction (MI) risk and the changes in metabolic risk factors among 717/612 patients/controls, with the aim of constructing a predictive nomogram. The genotype/allele distributions differed significantly between the 2 groups for T-429C ( P genotype/allele = .004/.001) and G1704T ( P < .001/.001). T-429C was significantly associated with MI risk, especially under a recessive model (adjusted odds ratio: 2.24, 95% confidence interval: 1.33-3.79, P = .003). For G1704T, significance was detected under additive (1.37; 1.12-1.67; P = .002) and recessive (3.86; 2.27-6.57; P < .001) models. There were significant differences in blood pressure and low-density lipoprotein cholesterol (LDL-C) across T-429C genotypes and in total cholesterol and LDL-C across G1704T genotypes. The overall best multifactor dimensionality reduction model included dyslipidemia, G1704T, and T-429C. Further predictive nomogram on 2 significant polymorphisms, blood pressure and lipids, showed a better predictive capability (concordance index = 0.716, P < .001). Altogether, we identified 2 polymorphisms of RAGE, T-429C and G1704T, which interacted with metabolic risk factors associated with the occurrence of MI. We also constructed a genetic-metabolic nomogram that can better predict MI risk.

Background: Nance-Horan Syndrome (NHS) (OMIM: 302350) is a rare X-linked developmental disorder characterized by bilateral congenital cataracts, with occasional dental anomalies, characteristic dysmorphic features, brachymetacarpia and mental retardation. Carrier females exhibit similar manifestations that are less severe than in affected males., Methods: Here, we report a four-generation Chinese family with multiple affected individuals presenting Nance-Horan Syndrome. Whole-exome sequencing combined with RT-PCR and Sanger sequencing was used to search for a genetic cause underlying the disease phenotype., Results: Whole-exome sequencing identified in all affected individuals of the family a novel donor splicing site mutation (NM&#95;198270: c.1045 + 2T > A) in intron 4 of the gene NHS, which maps to chromosome Xp22.13. The identified mutation results in an RNA processing defect causing a 416-nucleotide addition to exon 4 of the mRNA transcript, likely producing a truncated NHS protein., Conclusions: The donor splicing site mutation NM&#95;198270: c.1045 + 2T > A of the NHS gene is the causative mutation in this Nance-Horan Syndrome family. This research broadens the spectrum of NHS gene mutations, contributing to our understanding of the molecular genetics of NHS.

Background: Adolescent idiopathic scoliosis exhibits high heritability and is one of the most common spinal deformities found in adolescent populations. However, little is known about the disease-causing genes in families with adolescent idiopathic scoliosis exhibiting Mendelian inheritance., Objective: The aim of this study was to identify the causative gene in a family with adolescent idiopathic scoliosis., Methods: Whole-exome sequencing was performed on this family to identify the candidate gene. Sanger sequencing was conducted to validate the candidate mutations and familial segregation. Real-time QPCR was used to measure the expression level of the possible causative gene., Results: We identified the mutation c.2645A>C (p.E882A) within the AKAP2 gene, which cosegregated with the adolescent idiopathic scoliosis phenotypes. AKAP2 is located in a previously reported linkage locus (IS4) on chromosome 9q31.2-q34.2 and has been implicated in skeletal development. The mutation was absent in dbSNP144, ESP6500 and 503 ethnicity-matched controls. Real-time QPCR revealed that the mRNA expression level in the patients was increased significantly compared with the family controls (p<0.0001)., Conclusions: AKAP2 was therefore implicated as a novel gene mutated in a Chinese family with adolescent idiopathic scoliosis. Further studies should be conducted to validate the results from the perspective of both the genetics and pathogenesis of this disease., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/)

Autism is a neurodevelopmental disorder with unclear etiology. Reelin had been proposed to participate in the etiology of autism due to its important role in brain development. The goal of this study was to explore the association and gene-gene interactions of reelin signaling pathway related genes (RELN, VLDLR, LRP8, DAB1, FYN, and CDK5) with autism in Han Chinese population. Genotyping data of the six genes were obtained from a recent genome-wide association study performed in 430 autistic children who fulfilled the DSM-IV-TR criteria for autistic disorder, and 1,074 healthy controls. Single marker case-control association analysis and haplotype case-control association analysis were conducted after the data was screened. Multifactor dimensionality reduction (MDR) was applied to further test gene-gene interactions. Neither the single marker nor the haplotype association tests found any significant difference between the autistic group and the control group after permutation test of 1,000 rounds. The 4-locus MDR model (comprising rs6143734, rs1858782, rs634500, and rs1924267 which belong to RELN and DAB1) was determined to be the model with the highest cross-validation consistency (CVC) and testing balanced accuracy. The results indicate that an interaction between RELN and DAB1 may increase the risk of autism in the Han Chinese population. Furthermore, it can also be inferred that the involvement of RELN in the etiology of autism would occur through interaction with DAB1., (© 2015 International Society for Autism Research, Wiley Periodicals, Inc.)

Charcot-Marie-Tooth disease 2A (CMT2A), caused by mutations in the mitofusin 2 gene (MFN2), is the most common CMT2 subtype. The aim of our study is to assess the frequency and summarize the genetic and clinical characteristics of Chinese CMT2A patients. A total of 17 coding exons of MFN2 were detected by direct sequencing in 82 unrelated Chinese families diagnosed as CMT2. Clinical evaluations were analyzed among CMT2A patients. We identified 14 missense variants in 9 sporadic and 6 familial cases, including four novel mutations (T129A, S249F, Q367P, and Q674L), 4 known mutations (R94W, R94Q, T105M, C132Y, M376V and Q751X), and 4 rare missense variants (K120E, C217F, K307E and T356S). A total of 23 patients had early-onset phenotype. Two patients had a CMTNS score of 0 to 10; 16 had a score of 11 to 20; and 7 had a score greater than 20. Five patients were confirmed a de novo origin. Six of 14 variants were located or closed to the GTPase domain. We report four novel mutations and four rare missense variants. MFN2 mutations account for 18% of CMT2 families in mainland China. The common characteristics of Chinese pedigree are early disease onset and moderate phenotypes., (© 2016 Peripheral Nerve Society.)

Recently, mutations in transmembrane protein 240 (TMEM240) were identified as the cause of spinocerebellar ataxia type 21 (SCA21) in several French families. Clinically, SCA21 is characterized as an early-onset, slowly progressive cerebellar syndrome typically associated with cognitive impairment. To date, molecular screening of SCA21 has not been reported among patients of other ethnic origins or in other areas. Here we used Sanger sequencing to detect mutations in exons of TMEM240 in 340 unrelated probands with spinocerebellar ataxia for whom commonly known causative mutations have been excluded (96 probands of autosomal dominant spinocerebellar ataxia families and 244 patients with sporadic spinocerebellar ataxia). As a result, a de novo missense mutation (c.509C > T/p.P170L) was identified in one sporadic SCA patient. The condition manifested as early-onset (30 years old), slowly progressive cerebellar ataxia accompanied by mild early evidenced mental retardation, mild frontal behavior disorders and intentional hand tremors. Although rare, a SCA21 case was identified and described in mainland China, thus broadening the ethnic distribution of SCA21 beyond French families.

This study aimed to investigate the validity and reliability of the Chinese parent version of the Autism Spectrum Rating Scale (ASRS, 6-18 years) for a general sample of Chinese children. The study involved assessing 1625 community-based subjects aged 6-12 years from four sites (Shanghai, Guangzhou, Changsha, and Harbin city) in China and 211 clinic-based participants aged 6-18 with a confirmed diagnosis of autism spectrum disorders (ASDs). The internal consistency (Cronbach's alpha) ranged from 0.585 to 0.929, and the test-retest reliability (interclass correlations) ranged from 0.542 to 0.749, indicating no significant difference between the two tests at an interval of 2-4 weeks. The construct validity was relatively excellent, and the concurrent validity with the Social Responsiveness Scale (SRS) (Pearson correlations) was 0.732 between the two total scores. Receiver operating characteristics (ROC) analyses showed excellent and comparable discriminant validity of the ASRS with respect to the SRS, with an area under the curve (AUC) of 0.9507 (95% CI: 0.93-0.97) versus 0.9703 (95% CI: 0.96-0.98), respectively. Our data suggested a cutoff ≥60 for the Chinese version of the ASRS, with good accuracy in screening autism symptoms (sensitivity=94.2%, specificity=77%). The Chinese parent version of the ASRS is therefore a reliable and valid tool for screening autistic symptoms in Chinese children in general., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Autism is a childhood neurodevelopmental disorder with high heterogeneity. Following our genome-wide associated loci with autism, we performed sequencing analysis of the coding regions, UTR and flanking splice junctions of AMPD1 in 830 Chinese autism individuals as well as 514 unrelated normal controls. Fourteen novel variants in the coding sequence were identified, including 11 missense variants and 3 synonymous mutations. Among these missense variants, 10 variants were absent in 514 control subjects, and conservative and functional prediction was carried out. Mitochondria activity and lactate dehydrogenase assay were performed in 5 patients' lymphoblast cell lines; p.P572S and p.S626C showed decreased mitochondrial complex I activity, and p.S626C increased lactate dehydrogenase release in medium. Conclusively, our data suggested that mutational variants in AMPD1 contribute to autism risk in Han Chinese population, uncovering the contribution of mutant protein to disease development that operates via mitochondria dysfunction and cell necrosis.

It has been reported that some single-nucleotide polymorphisms (SNPs) are associated with the risk of Parkinson's disease (PD), but whether a combination of these SNPs would have a stronger association with PD than any individual SNP is unknown. Sixteen SNPs located in the 8 genes and/or loci (SNCA, LRRK2, MAPT, GBA, HLA-DR, BST1, PARK16, and PARK17) were analyzed in a Chinese cohort consisting of 1061 well-characterized PD patients and 1066 control subjects from Central South of Mainland China. We found that Rep1, rs356165, and rs11931074 in SNCA gene; G2385R in LRRK2 gene; rs4698412 in BST1 gene; rs1564282 in PARK17; and L444P in GBA gene were associated with PD with adjustment of sex and age (p < 0.05) in the analysis of 16 variants. PD risk increased when Rep1 and rs11931074, G2385R, rs1564282, rs4698412; rs11931074 and G2385R, rs1564282, rs4698412; G2385R and rs1564282, rs4698412; and rs1564282 and rs4698412 were combined for the association analysis. In addition, PD risk increased cumulatively with the increasing number of variants (odds ratio for carrying 3 variants, 3.494). In summary, we confirmed that Rep1, rs356165, and rs11931074 in SNCA gene, G2385R in LRRK2 gene, rs4698412 in BST1 gene, rs1564282 in PARK17, and L444P in GBA gene have an independent and combined significant association with PD. SNPs in these 4 genes have a cumulative effect with PD., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Background: Retinitis pigmentosa (RP) is a group of inherited retinal dystrophies characterized by night blindness, progressive peripheral visual field loss, and loss of central vision. Fifty-three RP pathogenic genes are responsible for RP. Pre-mRNA processing factor 31(PRPF31) gene is the third most common cause of autosomal dominant retinitis pigmentosa (adRP), and so far more than 40 mutations in PRPF31 have been detected., Purpose: To identify the underlying genetic defect in a five-generation Chinese family affected with adRP and to study the genotype-phenotype relationship of this family., Methods: Detailed clinical investigations were undertaken and peripheral blood samples were collected from 25 individuals. Microsatellite (STR) markers tightly linked to genes known to be responsible for adRP were selected for linkage analysis. Exons and adjacent splice junctions of the candidate gene were amplified and sequenced., Results: This adRP family exhibited an incomplete penetrance of the RP phenotype. In affected individuals, age of disease onset was from infancy to 4 years of age. Typical RP features were associated with this mutation. Linkage analysis identified a maximum two-point LOD score of 3.20 with D19S418, which is close to PRPF31. A mutation PRPF31: (c.358-359 del AA) was identified by linkage analysis., Conclusions: A PRPF31 mutation was identified to be responsible for adRP in a large Chinese family. Our findings expand the mutation spectrum of RP in the Chinese population.

The GGGGCC repeat expansion in the C9orf72 gene was recently identified as a major cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) in white populations. To estimate the frequency of hexanucleotide repeats in patients with ALS and FTD from mainland China, we screened for C9orf72 in a cohort of 128 patients and 150 control subjects using the repeat-primed polymerase chain reaction method. We observed pathogenic repeat expansions in a family with ALS-FTD and in a patient with sporadic FTD. In the family with ALS-FTD, the proband and the 2 asymptomatic siblings exhibited C9orf72 repeat expansions, and the clinical feature of the proband was characterized by pure motor syndrome with no cognitive impairment. The patient with sporadic FTD presented primarily with deteriorating behavior and mental status. Genotype analysis revealed that the proband shared the previously reported 20-single nucleotide polymorphism risk haplotype, whereas the patient with sporadic FTD carried all single nucleotide polymorphisms except rs2814707-A. To our knowledge, this study is the first to report 2 C9orf72 mutation patients in mainland China, and they shared the similar risk haplotype identified in white populations, suggesting that ALS and FTD associated with C9orf72 mutation was probably derived from a single founder., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Background: Recent studies suggest that epigenetic factors may play an important role in the pathogenesis of Parkinson's disease (PD). In our previous work, we sequenced the exomes of sixteen patients from eight Chinese PD families using whole exome sequencing technology, consequently three patients from different pedigrees were found sharing the variant c.1460C > T (rs150689919) in the coding region of the Tet methyl cytosine dioxygenase 1 (TET1) gene., Methods: In order to evaluate the possible association between sporadic PD and the single nucleotide polymorphism (SNP) rs150689919 in TET1, a case-control cohort study was conducted in 514 sporadic PD patients and 529 normal controls. Genotyping was determined by PCR and direct sequencing. Statistical significance was analyzed by the Chi-squared test., Results: There was no statistical significance in TET1 rs150689919 genotype or allele frequencies between the PD cases and healthy controls, even after being stratified by gender and age at onset., Conclusions: Our findings suggest that rs150689919 in TET1 may not be associated with PD in Chinese population. However, due to the limited data in this study, replication studies in larger sample and other populations are required.

Tumor necrosis factor superfamily member 4 (TNFSF4) plays a key role in the process of atherosclerosis, a common risk factor for both myocardial and cerebral infarctions. Recent studies indicate that the single nucleotide polymorphism (SNP) rs3850641 in TNFSF4 is associated with higher risk of myocardial infarction, but little is known about the association between TNFSF4 variation and cerebral infarction (CI). A case-control study involving 385 CI patients and 385 age-matched, sex-matched non-CI controls was conducted in a Chinese population, only the most common subtype, atherosclerosis CI, was recruited. Two SNPs of TNFSF4, rs3850641 and rs3861950, were genotyped by the TaqMan SNP genotyping method, and verified partly by genomic DNA sequencing. The results revealed a significant allelic association between rs3861950 and CI (Odds ration = 1.733, 95 % confidence interval = 1.333-2.254, P = 0.000). Genotypic association analysis demonstrated that the CC genotype of rs3861950 confers susceptibility to CI (Odds ration = 2.896, 95 % confidence interval = 1.368-6.132), and it was associated with a significantly higher risk of ischemic stroke (Odds ration = 3.520, 95 % confidence interval = 1.546-8.015, P = 0.003) after adjusting for the other confirmed risk factors such as the history of hypertension, diabetes, CAD, smoking and alcohol drinking. While the odds ratio of the T allele to the C allele was 1.733 (95 % confidence interval: 1.333-2.254). However, there was no significant association between rs3850641 and CI (Odds ration = 1.288, 95 % confidence interval = 0.993-1.670, P = 0.056). TNFSF4 gene polymorphism rs3861950, but not rs3850641, is associated with the risk of atherosclerosis CI in a Chinese population.

Background: The association between family history and risk of triple negative breast cancer and ductal carcinoma in situ (DCIS) has not been well investigated, especially in Asian populations. We investigated the association between family history and risk of DCIS or triple negative breast cancer in a Han Chinese population., Methods: A case-control study, comprising 926 breast cancer patients and 1,187 benign breast disease controls, was conducted in our hospital. Multivariate logistic regression was used to assess the relationships between family history and risk of DCIS or triple negative breast cancer., Results: Subjects with a family history of breast cancer had higher breast cancer risk than those without a family history (odds ratio (OR) = 2.11, 95% confidence interval (CI) = 1.26 to 3.52). Family history was not significantly associated with an increased risk of DCIS (OR = 1.27, 95% CI = 0.36 to 4.46), while family history was significantly associated with an increased risk of invasive breast cancer (OR = 2.22, 95% CI = 1.32 to 3.75), irrespective of triple negative breast cancer (OR = 3.35, 95% CI = 1.43 to 7.88) or non-triple negative breast cancer (OR = 2.14, 95% CI = 1.21 to 3.80)., Conclusion: Our results indicate that having a family history of breast cancer is associated with an increased risk of triple negative breast cancer with a magnitude of association similar to that for non-triple negative breast cancer. Furthermore, family history is not significantly associated with an increased risk of DCIS. Future cohort studies with larger sample sizes are still needed to explore these relationships.

8-hydroxy-2'-deoxyguanine (8-OHdG), a typical product of oxidative stress-induced DNA damage, can cause a G-T transversion during DNA replication if it is not removed. Human 8-oxoguanine glycosylase 1 (hOGG1), a key DNA repair gene, recognizes and excises 8-OHdG from damaged DNA accurately; however, a c.977C>G (Ser326Cys) polymorphism in hOGG1 can inhibit the gene's ability to remove 8-OHdG. The aim of present study was to investigate the association between the c.977C>G polymorphism in hOGG1 and the risk of breast cancer in Chinese Han women. We used high-resolution melting and sequencing to analyze the genotypes of 630 patients with sporadic breast cancer patients and 777 healthy controls. We also performed risk-stratified subgroup analyses to determine the association between the c.977C>G polymorphism and other characteristics of breast cancer subgroups. Breast cancer patients and healthy controls did not have significantly different of c.977C/G genotypes (odds ratio [OR] = 1.10, 95% confidence interval [CI] = 0.82-1.49, p = 0.57) and c.977G/G genotypes (OR = 1.34, 95% CI = 0.97-1.84, p = 0.09). However, the c.977G/G genotype was especially prevalent in breast cancer patients who were younger than 55 years (OR = 1.58, 95% CI = 1.05-2.39, p = 0.04), were premenopausal status (OR = 1.87, 95% CI = 1.14-3.06, p = 0.02), had triple-negative disease (OR = 2.14, 95% CI = 1.06-4.29, p = 0.04), or p53-positive disease (OR = 1.56, 95% CI = 1.14-2.12, p = 0.005). These findings suggest that the c.977C>G polymorphism in hOGG1 is associated with an increased risk of breast cancer in Chinese Han women who are younger than 55 years, premenopausal, triple-negative, or p53-positive subgroups., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Benign familial infantile seizure (BFIS) and paroxysmal kinesigenic dyskinesia (PKD) are autosomal-dominant inherited self-limited neurological disorders. BFIS is characterized by clusters of epileptic seizures in infancy while, in some cases, infantile seizures and adolescent-onset paroxysmal kinesigenic choreoathetosis co-occurred, which is called infantile convulsions and choreoathetosis (ICCA) syndrome. We and other researchers have reported the proline-rich transmembrane protein 2 (PRRT2) as the causative gene of PKD. We and our collaborators also identified PRRT2 mutations in ICCA and other phenotypes. Here we collected two BFIS families of Chinese Han origin. The linkage analysis has mapped the BFIS-causing locus to 16p12.1-q12.2, where PRRT2 is located. We then performed mutation analysis of PRRT2 by direct sequencing and identified c.649-650insC mutation in all BFIS patients. We also noticed that paroxysmal diseases (such as BFIS, PKD and ICCA) with PRRT2 mutations, instead of other forms, share some characteristics like being responded well to anti-epiletic treatment, we thus suggest to name them as PRRT2-related paroxysmal diseases (PRPDs) in order to assist clinical diagnosis and treatment., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

The glucocerebrosidase (GBA) gene mutation is emerging as an important risk factor for Parkinson's disease. We previously reported that the GBA gene L444P mutation is an important risk factor for PD in the Chinese population. The prevalence of this mutation in other neurodegenerative diseases and movement disorders remains completely unexplored in mainland China. In the present study, we extended the screening of GBA gene L444P mutation to Chinese patients with essential tremor (ET) and multiple system atrophy (MSA). We searched for the GBA gene L444P mutation in 109 patients with ET, 54 patients with MSA, and 657 controls from mainland China. None of the 109 patients with ET or 54 patients with MSA carried the GBA gene L444P mutation. Among the 657 controls, we found one L444P heterozygote. The difference in mutation frequencies between patients with ET or MSA and the control group was not statistically significant (chi-squared test, p = 1, respectively). The results suggest that the GBA gene L444P mutation may be not responsible for ET in mainland China. Whether the GBA gene L444P mutation modifies the risk for MSA deserves further study in larger samples., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

The spinocerebellar ataxias (SCAs) are a clinically and genetically heterogeneous group of neurodegenerative diseases. In 2010, four missense mutations in the prodynorphin (PDYN) gene were found in two families and two sporadic cases of SCA type 23 (SCA23) from the Netherlands. In addition, one missense mutation in PDYN was also found in one sporadic SCA23 case in America in 2012. To date, there have been no reports of PDYN gene mutations in mainland China. To investigate the frequency of SCA23 among the Chinese Han population, we performed polymerase chain reaction (PCR) and DNA direct sequencing of the PDYN gene in 305 unrelated ataxia patients. Although no SCA23 mutation was identified, one novel single nucleotide polymorphism (c.255G>A, p.Lys85Lys) in exon 4 of the PDYN gene was found. This suggests that SCA23 is a rare form of dominant ataxia in the Chinese Han population., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

Autosomal dominant cerebellar ataxias (ADCAs) are a clinically and genetically heterogeneous group of neurodegenerative disorders primarily affecting the cerebellum. Nearly 33 genetically distinct subtypes have been defined, and 19 seemingly unrelated disease genes have been identified so far. Recently, mutations in the ATPase family gene 3-like 2 (AFG3L2) gene were presented to cause SCA28 subtype. In order to define the frequency of SCA28 mutation in Chinese mainland, we performed molecular genetic analysis in 67 unrelated affected individuals with ADCA. At last, we did not find AFG3L2 gene mutation, except for three known single nucleotide polymorphisms (SNP)s. It suggests that SCA28 subtype is very rare in Chinese mainland.

VPS35 gene mutation has recently been reported in autosomal-dominant, late-onset Parkinson disease (PD). There are no reports regarding the association between VPS35 and Parkinson's disease (PD) in the Chinese population. We conducted a comprehensive genetic analysis of VPS35 gene in a cohort of twenty seven probands belonging to families with autosomal-dominant, late-onset PD, followed up with screening of specific variants in a separate group of 1011 sporadic PD patients and 1016 healthy controls. Our analysis revealed two exonic variants and three intronic variants across the entire VPS35 gene. There was no statistical difference in genotype or allele frequencies of rs3743928 and IVS14-24 t > c variants in VPS35 gene between sporadic PD group and healthy control group. None of the 1011 sporadic PD patients and 1016 controls carried the VPS35 gene c.1858G > A (p.Asp620Asn) mutation. Our data indicated that the VPS35 variants are not associated with PD in the mainland Chinese population., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Loss-of-function mutations in filaggrin gene (FLG; OMIM #135940) have been reported to cause the semi-dominant keratinizing disorders such as ichthyosis vulgaris (IV; OMIM #146700) and atopic dermatitis (AD; OMIM #605803). Recent linkage analysis and immunohistochemical studies suggest the possible contribution of FLG to psoriatic susceptibility. However, no susceptibility variant in FLG gene associated with psoriasis (OMIM #177900) has been identified. In this study, we identified a non-sense mutation of FLG (p.K4022X) in a Chinese psoriasis/IV coexisting family. The homozygous p.K4022X mutation was detected in a psoriasis patient, whereas the heterozygous p.K4022X mutation was identified in two IV patients and four apparently normal family members. We also genotyped p.K4022X variant in 441 sporadic Chinese psoriasis patients and found homozygous mutation in two patients, while no homozygous variant was found in 500 control individuals. After sequencing the entire coding region of FLG gene in 441 psoriasis patients, we identified another five mutations (p.R826X, p.W2583X, c.7945delA, c.3321delA and p.Q2417X). Although all six FLG mutations as a whole was not significantly associated with psoriasis (P = 0.105), mutation p.K4022X was significantly associated with psoriasis (P < 0.05). Our data thus indicates an association of FLG with psoriasis in Chinese population.

Autosomal dominant cerebellar ataxias (ADCAs), genetically classified into spinocerebellar ataxias (SCAs), are a highly heterogeneous group of neurodegenerative disorders. Recently, mutations in the fibroblast growth factor 14 gene (FGF14) have been reported to cause SCA27 subtype. To evaluate the frequency of FGF14 mutations in mainland of China, we performed molecular genetic analysis in 67 unrelated familial ataxia cases and 500 normal controls by denaturing high-performance liquid chromatography (DHPLC) and DNA direct sequencing. Interestingly, we found a pair of siblings carried the same heterozygous variation (c.-10delC) characterized by different clinical features, which is probably a novel insertion/deletion (I/D) polymorphism in the 5'UTR region of the exon 1b. It suggests that SCA27 is a rare subtype in China., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

Two novel single nucleotide polymorphisms (SNPs) (rs6812193 and rs11868035) were recently identified to be associated with Parkinson's disease (PD) in a Web Based Genome-Wide Association Study. Herein, we conducted a case-control study to evaluate the possible associations between these two SNPs and PD in Chinese Han population. All subjects (501 sporadic PD patients and 502 normal controls) were genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis with these two SNPs. Chi-square test revealed no significant difference in either genotype frequencies or allele frequencies, even after being stratified by age. But we found that the genotype and allele frequency of rs6812193 shows difference between male patients and male controls (p=0.031, OR=0.584; p=0.037, OR=0.606) but none in the female. Our findings suggest that rs11868035 may have no association with PD in Chinese population and rs6812193 may have marginal association with PD in male Chinese population. However, due to the limited data in the present study, replication studies in larger sample and other populations are required., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

Huntington's disease (HD) is caused by the abnormal expansion of CAG repeats in the huntingtin gene (HTT). The adjacent proline-rich region, which also has a CCG polymorphism among people of different races, may also affect the pathogenesis of HD. To study the effect of this polymorphism on patients with HD in mainland China, 53 HD mutant alleles were examined. The results showed that 54.72% of the HD mutant alleles had 10-repeat alleles, and the remaining 45.28% had 7-repeat alleles. Moreover, comparison of the clinical features between the two groups revealed no significant difference. We also investigated its effect on the aggregates in vitro. No significant difference was detected when the morphology and size of the aggregates with the two polymorphisms was compared in cells. Given these findings, it was quite reasonable to suppose that the CCG polymorphism may not influence the pathogenesis of patients with HD in mainland China., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Parkinson's disease (PD) is a common neurodegenerative disease resulting from complex interaction involving genetic and environmental risk factors on background of aging. In terms of genetic risk factors, recent studies provided a growing number of evidence for the idea that certain polymorphisms in familiar Parkinsonism genes may contribute to risk for sporadic PD in populations of specific ethnic backgrounds. To address this issue, a case-control study was conducted to determine the prevalence of LRRK2 Pro755Leu variant in 401 patients with sporadic PD and 398 unrelated healthy controls in Han population from mainland China. Heterozygous LRRK2 Pro755Leu variant was found in four patients and two healthy controls, but no statistical differences in genotypic or allelic frequencies between PD and control groups (genotype: P=0.686; allele: P=0.687) were detected. Furthermore, to evaluate its role in ethnic Chinese population, a meta-analysis was performed on Pro755Leu in population of Chinese ancestry throughout Asia. And it was detected at a similar frequency in PD and control cohort (Z=0.48, P=0.63, odds ratio=1.44, 95% CI: 0.32-6.40). Given these findings, it was quite reasonable to suppose that LRRK2 Pro755Leu variant rarely increased risk for PD in ethnic Chinese population in Asia., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

The ubiquitin carboxy-terminal hydrolase L1 gene (UCH-L1) has been implicated in the etiology of Parkinson's disease (PD). In several previous studies, an S18Y (C54A) polymorphism in exon 3 of the UCH-L1 gene has been found to be protective against PD. We performed polymerase chain reaction-restriction fragment length polymorphism analysis for DNA samples from 408 Chinese patients with PD and 398 Chinese healthy controls. For the S18Y variant, there was no significant difference either in the individual allele or genotype frequencies between cases and control subjects. Possession of the S18Y variant did not alter the risk of developing PD (odds ratio: 0.827; 95% confidence interval=0.596-1.147). There was no statistically significant difference in terms of age or sex distribution between the patients and controls (p>0.05). Overall, considering our present results together with those of our previous studies, we now have access to data from more than 1000 patients from different regions of China, supporting the conclusion that the S18Y polymorphism may not have a protective effect against PD in the Chinese population., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Purpose: Norrie disease (ND), a rare X-linked recessive disorder, is characterized by congenital blindness and, occasionally, mental retardation and hearing loss. ND is caused by the Norrie Disease Protein gene (NDP), which codes for norrin, a cysteine-rich protein involved in ocular vascular development. Here, we report a novel mutation of NDP that was identified in a Chinese family in which three members displayed typical ND symptoms and other complex phenotypes, such as cerebellar atrophy, motor disorders, and mental disorders., Methods: We conducted an extensive clinical examination of the proband and performed a computed tomography (CT) scan of his brain. Additionally, we performed ophthalmic examinations, haplotype analyses, and NDP DNA sequencing for 26 individuals from the proband's extended family., Results: The proband's computed tomography scan, in which the fifth ventricle could be observed, indicated cerebellar atrophy. Genome scans and haplotype analyses traced the disease to chromosome Xp21.1-p11.22. Mutation screening of the NDP gene identified a novel nonsense mutation, c.343C>T, in this region., Conclusions: Although recent research has shown that multiple different mutations can be responsible for the ND phenotype, additional research is needed to understand the mechanism responsible for the diverse phenotypes caused by mutations in the NDP gene.

Objective: To assist the establishment of platform and provide the reference standard for mutation detection in spinocerebellar ataxia (SCA) subtypes 1, 2, 3, 6, 7, 8, 10, 12, 17 and dentatorubral-pallidoluysian atrophy (DRPLA) in Chinese Han population., Methods: The nucleotide repeat numbers of the 9 SCA subtypes and DRPLA were detected using fluorescence-PCR and capillary gel electrophoresis technique in 300 healthy Chinese Han individuals., Results: Among the 300 healthy controls, the range of the CAG trinucleotide repeat number was 17 to 35 in SCA1, 14-28 in SCA2, 13-41 in SCA3/MJD, 4-16 in SCA6, 5-17 in SCA7, 5-21 in SCA12, 23-41 in SCA17, and 12-33 in DRPLA; and the range of CTA/CTG trinucleotide repeat number on SCA8 locus was 12-43 and the range of ATTCT pentanucleotide repeat number on SCA10 locus was 9-32. Of which, the 12 CTA/CTG repeats of SCA8, 9 ATTCT repeats of SCA10, 23 CAG repeats of SCA17 were the shortest normal repeat number, while the 41 CAG repeats of SCA3/MJD, 32 CAG repeats of SCA10 were the largest normal number that have not been reported., Conclusion: The normal ranges of polynucleotide repeats of different subtypes of SCA vary with geographical areas and ethnicities. It might be associated with the genetic and ethnic backgrounds. This is the first normal reference standard of polynucleotide repeat number of these ten SCA subtypes in Chinese Han.

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.

Objective: To investigate the CAG trinucleotide repeat expansion in spinocerebellar ataxia (SCA) types 1, 2, 3, 6, 7, 12, and 17 from Chinese Han., Methods: The pathological CAG triplet repeat expansions of the SCA1, SCA2, SCA3/Machado-Joseph disease (MJD), SCA6, SCA7, SCA12 and SCA17 genes were analyzed in a cohort of 559 Mainland Chinese patients affected by spinocerebellar ataxia, including 363 probands from families with autosomal dominant SCA and 196 sporadic cases. Polymerase chain reaction, agarose gel electrophoresis, recombinant DNA technology by T-vector cloning and direct sequencing were performed to detect the CAG-repeat number of abnormal allele., Results: Among the 559 SCA patients, twenty-three were positive for SCA1, the ranges of expanded CAG repeats were from 39 to 60 (mean:51.09+/-4.88); thirty-two were positive for SCA2, the ranges of expanded CAG repeats were from 36 to 51 (mean:40.34+/-4.40); three hundred and five were positive for SCA3/MJD, the ranges of expanded CAG repeats were from 49 to 86 (mean:73.84+/-5.07); nine were positive for SCA6, the ranges of expanded CAG repeats were from 23 to 29 (mean:25.56+/-1.94); twenty-seven were positive for SCA7, the ranges of expanded CAG repeats were from 38 to 71(mean:58.22+/-10.90); three were positive for SCA12, the ranges of expanded CAG repeats were from 51 to 52 (mean:51.33+/-0.58); and finally, two were positive for SCA17, the range of expanded CAG repeats were from 53 to 55 (mean:54.00+/-1.41)., Conclusion: The 39 CAG repeats of SCA1, 49 CAG repeats of SCA3 and 51 CAG repeats of SCA12 are all the shortest known causative expanded alleles, while the 86 CAG repeats of SCA3/MJD is the largest full expanded allele that has never been reported. Furthermore, it is the first report of SCA17 subtype in Mainland Chinese and first research that established the abnormal reference standard of CAG repeat number of different subtypes of SCA in Chinese Han.

Spinocerebellar ataxia type 17 (SCA17) is a rare autosomal dominant progressive neurodegenerative disease caused by the CAG/CAA expansion in the TATA box-binding protein (TBP) gene. This study aimed to assess the frequency of SCA17 in patients from mainland China. Analysis of CAG/CAA expansion in this gene was performed in 263 patients consisting of 100 probands with dominantly inherited ataxias and 163 patients with sporadic ataxias. Abnormal expansion of CAG/CAA repeats in the SCA17 locus was found in a proband and her younger sister. To our knowledge, we are providing the first kindred analysis of SCA17 in mainland China.

Purpose: To map the locus and identify the gene causing autosomal dominant congenital cataract (ADCC) with "snail-like" phenotype in a large Chinese family., Methods: Clinical and ophthalmologic examinations were conducted on family members and documented by slit lamp photography. Linkage analysis was performed with an initial 41 microsatellite markers, then 3 additional markers flanking the major intrinsic protein (MIP) gene. Mutations were screened by DNA sequencing and verified by restriction fragment length polymorphism (RFLP) analysis., Results: Significant two-point LOD scores were obtained at 5 markers flanking MIP with the highest 3.08 (theta=0.00) at marker D12S1632. Mutation screening of MIP identified a heterozygous G>A transition at the acceptor splice site of intron 3 (IVS3 -1 G>A), abolishing a BstSF I restriction site in one allele of all the affected individuals., Conclusions: We identified a novel splice-site mutation (IVS3 -1 G>A in MIP) in a Chinese ADCC family. To our knowledge, this is the first report on an acceptor splice-site mutation in human genes associated with ADCC.

Objective: To search for the dystrophin gene mutations of Duchenne muscular dystrophy (DMD) patients without gross deletions, in order to offer accurate genetic counseling and prenatal diagnosis for those families., Methods: All 79 exons of the dystrophin gene as well as its 5'-UTR and 3'-UTR of 14 Chinese DMD/Becker muscular dystrphy (BMD) patients without detectable gross deletions were screened by denaturing high performance liquid chromatography (DHPLC) and heteroduplex fragments were identified by subsequent sequencing., Results: Seven causative point mutations, including two novel ones, were detected in 7 patients. Fourteen known polymorphisms and 7 unknown intronic variations were also detected. Five mothers of the patients were obligate carriers., Conclusion: DHPLC is an efficient way of identifying point mutations and the female carriers in DMD families.

Objective: To study the normal range of (CTA/CTG)n repeats of ATXN8OS gene in Chinese Hans, and the frequency of ATXN8OS (CTA/CTG)n repeat expansion in spinocerebellar ataxia(SCA) patients in Mainland China., Methods: The (CTA/CTG)n repeats of ATXN8OS gene were detected using fluorescence-PCR, 8% denaturing polyacrylamide gel and capillary electrophoresis technique in 132 SCA patients in whom CAG expansion at the SCA1, SCA2, SCA3, SCA6, SCA7, SCA12, SCA17 and dentatorubral-pallidoluysian atrophy(DRPLA) loci has been excluded, and 261 healthy controls., Results: There were no obvious abnormal changes of the (CTA/CTG)n repeats of ATXN8OS gene in the 132 SCA patients. Thirty-five SCA patients were homozygotes (26.5%), and the range of CTA/CTG repeat number was 17 to 47 (24.20+/-4.57), among which 18 repeats appeared most frequently. In 261 normal controls, 70 were homozygotes (26.8%), and the range of the CTA/CTG repeat number was from 12 to 43 (24.04+/-4.53), among which 18 repeats was the most frequent., Conclusion: SCA8 is a rare subtype of SCA in Mainland China. The low prevalence of SCA8 seems to be correlated with the low frequency of large (CTA/CTG)n copy number alleles in Chinese population.

Purpose: Congenital motor nystagmus (CMN) is a relatively common oculomotor disorder characterized by bilateral uncontrollable ocular oscillations. Recently, the FRMD7 gene mutation has been identified as the genetic cause of CMN. The purpose of this study was to identify mutations of the FRMD7 gene in Chinese patients with CMN., Methods: Clinical data and genomic DNA of three Chinese CMN families were collected after informed consent. Genescan by two-point linkage analysis combined with haplotype analysis was performed and mutation screening of the FRMD7 gene was conducted by direct sequencing., Results: Maximum two-point LOD scores of 2.00, 1.76, and 1.16 at theta=0.00 were obtained with markers in proximity to the FRMD7 gene on chromosome Xp26 in the three CMN families. Mutation screening in the FRMD7 gene identified two novel missense mutations (c.781C>G and c.886G>C) and one reported nonsense mutation (c.1003C>T). These nucleotide alterations were not seen in unaffected members of the families or in 100 unrelated control subjects., Conclusions: This study widens the mutation spectrum of the FRMD7 gene.

Objective: To detect mutations of guanosine triphosphate cyclohydrolase I (GCH1) gene in Chinese patients with dopa responsive dystonia (DRD)., Methods: Six sporadic patients with DRD were examined. GCH1 gene mutations were detected using polymerase chain reaction (PCR), DNA sequence analysis and restriction enzyme digestion analysis. One hundred normal people were detected using PCR and restriction enzyme digestion analysis., Results: A new point mutation, 151(G-->A) in exon one was found in a patient. It lead to substitution of a methionine for isoleucine at amino acid 1(M1I). This mutation was not found in normal control people., Conclusion: The authors report a new heterozygotic point mutation 151(G-->A) in GCH1 gene. There are GCH1 gene mutations in Chinese sporadic patients with DRD.

Objective: To investigate the mutation characteristics of spastin gene in Chinese patients with hereditary spastic paraplegia (HSP) and thus provide a basis for the gene diagnosis of HSP., Methods: Mutation of spastin gene was screened by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) combined with DNA direct sequencing in 31 unrelated affected HSP individuals in China, of whom 22 were from autosomal dominant families and 9 were sporadic HSP patients. Co-segregation analysis was carried out after the finding of abnormal SSCP bands., Results: Six cases were found to have abnormal SCP bands, and among them, two missense mutations (T1258A, A1293G in exon 8) and one deletion mutation (1667delACT or 1668delCTA or 1669delTAC in exon 14) were found and all of them were not reported previously. They were all co-segregated with the disease and were localized within the functional domain of spastin gene. Besides, T1258A was seen in two unrelated families., Conclusion: The mutation rate (18.2%) in autosomal dominant HSP in Chinese patients is comparatively low. Point mutation is the major mutation type and exon 8 may be the mutation hot spot.

Objective: To report a Chinese Charcot-Marie-Tooth disease (CMT) family whose proband had abnormal brainstem auditory evoked potentials (BAEPs) and to study its relationship with connexin 32 (Cx32) gene mutation., Methods: All family members were studied through clinical examinations, out of them, the proband was subjected to electromyography and BAEPs examination. Mutation analysis of Cx32 was screened by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) combined with DNA direct sequencing in the proband, 8 family members and 50 unrelated normal individuals., Results: The proband had highly decreased nerve conduction velocities and delayed BAEPs. Leu131Pro mutation was found in the proband and 3 family members, not found in 50 normal controls., Conclusion: This mutation has not been reported previously. Central nervous system can be affected in CMT patients.