Kai Gao

Genetic analysis of the fused in sarcoma gene in Chinese Han patients with essential tremor

We conducted genetic analysis of the fused in sarcoma gene (FUS) in Chinese Han patients with essential tremor (ET) in a case-control association study. One hundred eighty unrelated patients with ET were screened for mutations in the coding region and exon-intron boundaries of FUS. Reverse transcriptase polymerase chain reaction analysis was performed to evaluate if the c.1176G>A variant results in change of splice site. Two hundred seventy-three normal control subjects were also analyzed when DNA variants were identified in ET cohort. A novel missense mutation, c.1176G>A (p.M392I), in FUS was identified in a 62-year-old patient. Four known variants (c.52C>A, p.P18T; c.147C>A, p.G49G; c.291T>C, p.Y97Y; c.684C>T, p.G228G) were observed in the case-control study without statistically significant differences in genotype and allele distributions. Mutation(s) in FUS might be associated with a small subset of ET cases in the Chinese population.

Genetic analysis of IREB2, FAM13A and XRCC5 variants in Chinese Han patients with chronic obstructive pulmonary disease.

Recently, variants (rs2568494, rs2869967 and rs3821104) in the IREB2, FAM13A and XRCC5 genes were found to be associated with chronic obstructive pulmonary disease (COPD) in non-Asian populations by genome-wide association study (GWAS) analysis. To evaluate whether variants in these genes are related to COPD in Chinese Han population, we investigated COPD patients of Chinese Han ethnicity from Mainland China. Significant differences in genotypic distributions (χ(2)=6.319, p=0.042 for rs2869967; χ(2)=6.062, p=0.048 for rs3821104) and allele distributions (χ(2)=4.014, p=0.045 for rs2869967; χ(2)=5.607, p=0.018 for rs3821104) were observed between patients and control subjects for variants rs2869967 and rs3821104, whereas no statistically significant associations for genotypic and allelic distribution between IREB2 rs2568494 and COPD phenotype (p>0.05) were identified. Our results support that FAM13A rs2869967 and XRCC5 rs3821104 are associated with COPD in Chinese Han population.

Identification of a novel COL4A5 mutation in a Chinese family with X-linked Alport syndrome using exome sequencing

Alport syndrome (AS) is an inherited disorder and clinically characterized by glomerulonephritis and end-stage kidney disease (ESRD). The aim of this study was to identify the gene responsible for glomerulopathy in a 4-generation Chinese pedigree. Exome sequencing was conducted in four patients of the family, and then direct sequencing was performed in other members of the pedigree. A novel missense mutation c.368G>A (p.Gly123Glu) in the collagen type IV alpha-5 gene (COL4A5) was found to be the genetic cause. The p.Gly123Glu mutation occurs prior to Gly-X-Y repeats in the alpha-5 chain of type IV collagen. Neither sensorineural hearing loss nor ocular abnormalities were present in patients of this family. Other clinical features, such as age of onset, age of ESRD, disease severity and complications, varied among patients of this family. Our finding may provide new insights into the cause and diagnosis of AS, and also have implications for genetic counseling.

VPS35 mutation in Chinese Han patients with late-onset Parkinson's disease.

Research in genetics of Parkinson’s disease (PD) has been extremely prolific in the last two decades, and at least 18 loci involved in parkinsonism have been identified through linkage analysis or genome-wide association studies [1]. Recent studies found that mutations in the vacuolar protein sorting 35 gene (VPS35) are responsible for late-onset PD in Swiss and Austrian pedigrees [2,3]. To determine the association between the VPS35 and late-onset PD in Chinese Han population, we carried out mutation analysis of the VPS35 gene in our patients with PD in Mainland China. Two hundred and two unrelated Chinese Han patients with late-onset PD (age at the study enrollment: 66.3 ± 8.4 years; age at PD onset, 62.2 ± 5.7 years; men/women, 102/100; 72 familial PD and 130 sporadic PD) were enrolled in this study. This study was approved by the Ethics Committee of the Third Xiangya Hospital and each individual has signed an informed consent. Coding regions and intron/exon boundaries of the VPS35 gene were PCR amplified and single-strand conformation polymorphism (SSCP) was employed. PCR products exhibiting the abnormally shifted bands were sequenced. Sequenced normal control and negative control (with no DNA sample) were set in every experiment. We did not detect any mutation in the coding region in the VPS35 gene in any of the 202 patients. Our result suggests that mutation in the VPS35 coding region probably does not represent a major cause of late-onset PD in the Chinese Han population. Alternatively, our sample size is not large enough to detect those low-frequency mutations of the VPS35 gene in patients with PD (Table 1) [4–7]. VPS35 directly associates with cargos, including soluble N-ethylmaleimidesensitive factor attachment protein receptor (SNARE) proteins, SORL1, SORT1, and MUL1 [2]. Among proteins whose gene responsible for gentic form of PD, alpha-synuclein promotes SNARE-complex assembly, whereas leucine-rich repeat kinase 2

Genetic analysis of the FBXO48 gene in Chinese Han patients with Parkinson disease.

The F-box only protein 48 gene (FBXO48) is located in 2p13.3, the disease gene locus of Parkinson disease type 3 (PARK3), and it is one of the paralogs of the F-box only protein 7 gene (FBXO7), which is a causative gene of the Parkinson disease type 15 (PARK15; also known as Parkinsonian-pyramidal disease, PPD). To determine whether genetic mutation in the coding region of the FBXO48 gene plays a role in the etiology of PD, we screened DNA samples from 350 Chinese Han patients with PD. No mutation in the coding region of the FBXO48 gene was identified in our PD cohort, suggesting that mutations in the coding region of the FBXO48 gene play little or no role in the development of PD.

MicroRNA‑133b inhibits connective tissue growth factor in colorectal cancer and correlates with the clinical stage of the disease.

Accumulating evidence indicates that dysregulation of microRNA‑133b (miR‑133b) is an important step in the development of certain types of human cancer and contributes to tumorigenesis. Altered expression of miR‑133b has been reported in colon carcinoma, but its association with clinical stage in colorectal cancer (CRC) has remained elusive. Connective tissue growth factor (CTGF), a potentially promising candidate gene for interaction with miR‑133b, was screened using microarray analysis. The expression of miR‑133b and CTGF was evaluated using reverse transcription‑quantitative polymerase chain reaction and western blot analysis. The regulatory effects of miR‑133b on CTGF were evaluated using a dual‑luciferase reporter assay. CTGF was identified as a functional target of miR‑133b. The results demonstrated low expression of miR‑133b in CRC specimens with poor cell differentiation (P=0.011), lymph node metastasis (P=0.037) and advanced clinical stages (stage III or IV vs. I or II; P=0.036). Furthermore, there was a significant association between a high level of expression of CTGF mRNA and an advanced clinical stage (stage III or IV vs. I or II; P=0.015) and lymph node metastasis (P=0.034). CTGF expression was negatively regulated by miR‑133b in the human colorectum, suggesting that miR‑133b and CTGF may be candidate therapeutic targets in colorectal cancer.

Genetic analysis of the fused in sarcoma gene in Chinese Han patients with Parkinson's disease

BACKGROUND AND PURPOSEnExome sequencing in a large essential tremor (ET) family identified a novel nonsense mutation (p.Q290X) in the fused in sarcoma gene (FUS) as the cause of this family. Because of the clinical overlap between ET and Parkinsons disease (PD), the role of FUS in an independent cohort of PD patients from China mainland was evaluated.nnnMETHODSnThe entire coding region of FUS in 508 Chinese Han patients with PD and the identified variants in 633 normal controls were evaluated. A variant was further screened in an additional 382 controls for the frequency in our population.nnnRESULTSnA novel variant c.696C > T (p.Y232Y) in 2 sporadic patients with PD and six variants (c.52C > A, p.P18T; c.52C > T, p.P18S; c.147C > A, p.G49G; c.291C > T, p.Y97Y; c.684C > T, p.G228G; c.1176G > A, p.M392I) without significant difference in genotypic and allelic distributions in our PD cohort were identified.nnnCONCLUSIONnThe FUS gene is not a genetic risk factor for PD in the population of Chinese Han ethnicity.

Heterogeneous phenotype in a family with the FERM domain-containing 7 gene R335X mutation.

OBJECTIVEnInfantile nystagmus (IN) is characterized by bilateral involuntary, periodic, and predominantly ocular oscillations. In this article, we describe a mutation screen conducted on a 4-generation family in which 4 patients were affected with X-linked IN (XLIN).nnnDESIGNnExperimental study.nnnPARTICIPANTSnA 4-generation Chinese Han family including 4 symptomatic members with IN and 200 normal male controls.nnnMETHODSnDNA was extracted from peripheral blood, and the FERM domain-containing 7 gene (FRMD7) was amplified on DNA samples of all the available family members. The mutation screen was conducted by performing direct DNA sequencing.nnnRESULTSnA nonsense mutation (R335X) in the FRMD7 gene was identified in 4 male patients and an asymptomatic female member.nnnCONCLUSIONSnAlthough the R335X mutation in the FRMD7 gene has been previously described, the clinical features, including both disease penetrance and severity, among individuals with FRMD7 mutation in our family vary greatly. One female member with the heterozygous R335X mutation had no clinical manifestation of the disease. This incomplete penetrance suggests that random X-chromosome inactivation may play a role in the pathogenesis of IN, and that loss of functional FRMD7 may account for the development of this disorder. Our findings may be helpful in the genetic counseling of patients with nystagmus.

Genetic analysis of the ATP1B4

Parkinson’s disease (PD) is the second most common neurodegenerative disease characterized clinically by bradykinesia, resting tremor, rigidity and postural instability. Mutations in the ATPase 13A2 gene were found to be the causes for the Kufor-Rakeb syndrome, a rare form of recessively inherited atypical juvenile parkinsonism. The ATPase Na+/K+ transporting beta 4 polypeptide gene (ATP1B4) is located within a 19-centimorgen region of the PARK12 near the marker DXS1001 and it encodes a protein named βm, a member of P-type ATPases β-subunit family. To determine whether mutations in the ATP1B4 gene are associated with PD, we screened the coding region of this gene in 100 Chinese Han patients with PD. A known single nucleotide variant rs2072452 (c.143Txa0>xa0C), predicted to lead to amino acid substitution (p.Val48Ala), was identified. Extended analysis of 202 patients with PD and 400 gender, age, and ethnicity matched healthy controls showed no significant differences between patients and control subjects for genotypic and allelic distributions (Pxa0=xa00.638 for genotypic distribution; Pxa0=xa00.685 for allelic distribution in females and Pxa0=xa00.303 for allelic distribution in males), suggesting the variant in the coding region of the ATP1B4 gene may play little or no role in the development of PD in Chinese Han population.

Genetic analysis of the FBXO42 gene in Chinese Han patients with Parkinson’s disease

BackgroundParkinson’s disease (PD), the second most common neurodegenerative disease, is characterized by loss of dopaminergic neurons in the substantia nigra. The clinical manifestations of PD encompass a variety of motor and non-motor symptoms. Mutations in the F-box protein 7 gene (FBXO7) have been identified to cause Parkinsonian-pyramidal syndrome, an autosomal recessive form of Parkinsonism. The F-box protein 42 gene (FBXO42), a paralog of the FBXO7 gene, is involved in the ubiquitin-proteasome system that may play a role in the pathogenesis of PD.MethodsTo determine whether the FBXO42 gene is associated with PD, we performed a systematic genetic analysis of the FBXO42 gene in 316 PD patients and 295 gender-, age-, and ethnicity-matched normal controls.ResultsWe identified a novel variant c.1407T>C (p.S469S) and three known single nucleotide variants, including rs2273311, rs12069239 and rs35196193 in the FBXO42 gene in PD patient group. None of the three known variants displayed statistically significant difference in either genotypic or allelic distributions between patient and control groups (all P > 0.05). Haplotype analysis showed that a common haplotype (G-C-G) for the three single nucleotide variants conferred a 1.69-fold increased risk for PD (P = 0.008 after Bonferroni correction, OR = 1.69, 95% CI = 1.06-2.71).ConclusionsOur findings suggest that a haplotype of the FBXO42 gene might be associated with a higher susceptibility to PD.