1.Parental origin verification through chromosomal microarray analysis to determine the clinical significance of copy number variations
Hairong WU ; Lin LI ; Yinan MA ; Chunlian LIU ; Pei PEI ; Xuefei ZHENG ; Songtao WANG ; Yang XIAO ; Dingfang BU ; Yufeng XU ; Hong PAN ; Yu QI
Chinese Journal of Perinatal Medicine 2021;24(9):658-664
Objective:To explore the role of parental origin verification in chromosomal microarray analysis (CMA) on the determination of the clinical significance of copy number variations (CNVs).Methods:This retrospective study collected clinical information from 73 core families who underwent prenatal diagnosis at Peking University First Hospital from November 2017 to December 2019. Indications for prenatal diagnosis included ultrasound abnormality in 54 cases (including 12 with thickened nuchal translucency (≥2.5 mm), four with fetal growth restriction, seven with abnormal pregnancy history, and 31 with isolated ultrasound abnormality), NIPT indicated high-risk in four cases, advanced age in nine cases, abnormal pregnancy history alone in three cases, intrauterine death in two cases and one with maternal mental retardation. Genomic DNA of amniotic fluid sample, chorionic villi, cord blood, fetal tissues, and fetal heart blood were extracted using genomic DNA extraction kit. The CNVs of prenatal samples in 73 subjects were analyzed using array-based comparative genomic hybridization (array-CGH) analysis and single nucleotide polymorphism array (SNP-array). Peripheral blood DNA of the couples, and relevant families if necessary, were collected and analyzed in the same way. The results of parental origin detection in CMA were summarized.Results:A total of 76 CNVs were detected in these 73 samples, out of which nine were pathogenic and parental origin detection revealed that six were de novo, two were maternally, and one was paternally inherited; six CNVs were likely pathogenic, including three de novo, two maternally inherited and one paternally inherited; 20 CNVs were variants of uncertain significance, including five paternally inherited, three maternally inherited and 12 de novo; 41 CNVs were likely benign, among which 38 were inherited from parents with normal phenotype. Conclusions:Parental origin verification plays an important role in explaining the clinical significance of detected fetal CNVs and thereby can help to analyze its clinical effect and reproductive risk.
2.Assoaation of IL-10 gene single nucleotide polymorphisms with the acute susceptibility to lymphocyte leukemia
Ci WANG ; Xiaoling GUO ; Ping ZHU ; Dingfang BU ; Hongxing LIU ; Chengliang ZHEN ; Zheng WANG ; Ling PAN
Chinese Journal of Laboratory Medicine 2011;34(4):339-344
Objective To observe the relationship of IL-10 gene single nucleotide polymorphism and the susceptibility to ALL. Methods The bone marrow and peripheral blood samples from 115 ALL patients and 323 healthy controls were collected in Peking University First Hospital and Beijing Dao-pei Hospital from January 2007 to December 2009. The DNA were extracted from all samples. The primers of -819C/T and -592A/C in the promoter region of IL-10 gene were designed for the PCR. The restrictive fragment length polymorphism of IL-10 gene was analyzed by using restrictive enzyme Msl Ⅰ and HpyCH4 Ⅲ.Sequencing was done in part of these samples to confirm the results of PCR. The differences of genotypes and allele ratio of -819 and -592 sites were analyzed between the ALL patients and healthy controls. Real-time quantitative PCR was performed to detect the EB virus (EBV) infection and the expression of BCR/ABL fusion gene. The differences of genotypes and allele ratio of -819 and -592 sites were analyzed between the positive and negative group. Results The genotype ratios of -819CC, -819TT, - 819CT, -592AA,- 592CC and - 592AC were 14. 8% ( 17/115 ), 45.2% ( 52/115 ), 40. 0% ( 46/115 ), 43.5% ( 50/115 ),16. 5% ( 19/115 ), 40. 0% ( 46/115 ) in ALL patients, and were 9. 9% ( 32/323 ), 16. 4% ( 53/323 ),73.7% ( 238/323 ), 11.8% ( 38/323 ), 15.5% ( 50/323 ), 72. 8% ( 235/323 ) in the healthy controls,respectively. The genotypes of -819 and -592 sites had statistically significant differences between the two groups(x2 values were 46.000 and 54.550, all P < 0. 05 ). The allele ratio of -819T and -592A were (65.2%, 150/230) and (63.5%, 146/230) in ALL patients, while they were 53.5% (344/646) and 48. 1% (311/646)in the healthy controls. There were statistically significant differences between the two groups (x2 values were 9. 877 and 15.986, all P < 0. 05 ). The EBV DNA were detected in 42 ALL patients,among which 22 were positive and 20 were negative. The genotype ratios of -819CC, -819TT, -819CT,-592AA, - 592CC, - 592AC in EBV positive group were 9. 1% ( 2/22 ), 40. 9% ( 9/22 ), 50. 0%(11/22) ,31.8% ( 7/22 ), 13.6% ( 3/22 ), 54. 5% ( 12/22 ), while they were 35.0% ( 7/20 ), 45.0%(9/20) ,20. 0% (4/20) ,35.0% (7/20) ,45.0% (9/20) ,20. 0% (4/20) in the EBV negative group. The genotypes of -819 and -592 sites showed no statistical differences between the two groups( all P > 0. 05 ).The BCR/ABL fusion gene were detected in 36 ALL patients, among which 20 were positive and 16 were negative. The genotype ratios of - 819CC, - 819TT, - 819CT, - 592AA, - 592CC, - 592AC in BCR/ABL positive group were 0% (0/20) ,45.0% (9/20) ,55.0% ( 11/20), 45. 0% (9/20) ,5.0% (1/20) ,50. 0%( 10/20), while they were 18. 8% ( 3/16 ), 50. 0% ( 8/16), 31.3% ( 5/16 ), 50. 0% ( 8/16 ), 18. 8%(3/16), 31.3 % (5/16)in the BCR/ABL negative group. The genotypes of -819 and -592 sites showed no statistical differences between the two groups ( all P > 0. 05 ). Conclusion The population with - 819TT and - 592AA genotype of IL-10 gene shows susceptibility to ALL.
3.Proteins structure change of COL4A4 gene point mutation and its association with phenotype in thin basement membrane nephropathy
Qiuyuan FANG ; Yunfeng WANG ; Youkang ZHANG ; Suxia WANG ; Dingfang BU
Chinese Journal of Nephrology 2010;26(1):3-8
Objective To detect the proteins structure encoded by COL4A4 gene with different missense mutations of thin basement membrane nephropathy (TBMN) and to analyze the effect of gene mutation on the secondary structure of α4 (Ⅳ) chain and its association with phenotype. Methods A COL4A4-linked TBMN patient with FSGS by a missense mutation (g. 1214G>A resulting in p. G405E) diagnosed by clinical manifestations, family history and renal biopsy examination, as well as two controls (one healthy, one pure TBMN carrying a g. 1550G>A mutation resulting in p. G448S) were enrolled in this study. The fragments of cDNA with the two mutations and that of corresponding cDNA from the healthy control were expressed in E. coll. The secondary structures of recombinant polypeptides were analyzed by circular dichroism (CD) spectroscopy. Results CD spectra of healthy control exhibited a negative peak near 208 nm whereas that of TBMN patient with FSGS exhibited a negative peak near 220 nm. Furthermore, the magnitude of the negative peak of this patient decreased as compared with that of healthy control. CD spectra of pure TBMN control was slightly changed with the negative peak remaining near 208 run and the magnitude slightly decreased as compared with that of healthy control. In addition, the secondary structure of pelypeptide from healthy control was composed of about 1/4 α-helix and 1/4 β-sheet, whereas that from the patient presented about 1/3 α-helix without any β-sheet. The secondary structure of polypeptide from pure TBMN control was almost the same as the healthy control, except a shght reduction of α-helix and a slight increase of β-sheet. Conclusions Although the glycine substitutions exists in the nearby domain of α4 (Ⅳ)chain, the TBMN patient complicating FSGS with severe phenotype and g. 1214G>A mutation and the pure TBMN control with the mild phenotype and g. 1550G>A mutation are revealed with different secondary structures of α4 (Ⅳ)chain. Moreover, the secondary structure change of α4 (Ⅳ) chain is consistent with their corresponding phenotype severity.
4.Comparison of the clinical application of different methods for detection of NPM1 gene mutations in leukemia
Jiyan ZOU ; Ping ZHU ; Hongxing LIU ; Ying ZHANG ; He WANG ; Peng CAI ; Dingfang BU
Chinese Journal of Laboratory Medicine 2009;32(1):35-39
Objective To analyze nucleophosmin (NPM1) gene mutations in exon 12 in patients with acute myeloid leukemia (AML) and evaluate the clinical appliance of three methods which are frequently used for detecting gene mutation. Methods Genomic DNA from bone marrow of 54 AML patients was detected by PCR for NPM1 exon 12 and screened by PCR-capillary electrophoresis, denature high-performance liquid chromatography (DHPLC) and direct sequencing separately. FLT3-ITD (FMS-like tyrosine kinease internal tandem duplication) was detected by agarose gel electrophoresis and PCR-capillary electrophoresis. Results Seven AML sample harbored NPM1 gene mutations. Five of them were the most common mutation, known as type A (an insertion of a TCTG tetranucleotide at position 960 bp). One of them was type D (an insertion of a CCTG tetranuclectide at position 960 bp). The new variant was a deletion of a TGGCAGTG sequence at 958 bp and insertion of a GCCCGCGGTTTA sequence instead. The detection ratio of the three methods was all 100% and capillary electrophoresis was more rapid, reliable and easier than the other two methods. Moreover it could detect FLT3-ITD simultaneously. The resolving power of DHPLC was affected by many factors. The direct sequencing method was tedious and the heterozygous sequence might be misread. Conclusions There is a new mutation at position 958 bp with a 12-nucleotide insertion and substitution. PCR-capillary electrophoresis is convenient to screen NPM1 mutations of AML in clinical practice.
5.Propargylglycine up-regulated connective tissue growth factor expression in rat pulmonary artery with high pulmonary blood flow
Xiaohui LI ; Junbao DU ; Dingfang BU ; Hongfang JIN ; Chaoshu TANG
Basic & Clinical Medicine 2006;0(07):-
Objective To explore possible impact of endogenous hydrogen sulfide(H2S) on connective tissue growth factor(CTGF) expression in rat pulmonary artery with high pulmonary blood flow.Methods Thirty-two male SD rats,weighing 120~140 g,were randomly divided into 4 groups:shunt group,shunt+PPG group,sham group and sham+PPG group.After 4 weeks of experiment,Rat lung tissue H2S content was determined by a modified sulfide electrode method.Plasma ET-1 concentration was detected by radioimmunoactivity,and lung tissue ET-1 mRNA expression of rat was determined by quantitative competitive reverse transcriptional polymerase chain reaction(RT-PCR).Pulmonary artery connective tissue growth factor(CTGF) protein expression of rats was investigated by immunohistochemistry.Results After 4 weeks of experiment,lung tissue H2S content plasma ET-1,lung tissue ET-1 mRNA and CTGF expression increased significantly in rats of shunt group as compared with that of sham group(P
6.Influence of endogenous nitric oxide synthase /nitric oxide system on brain damage induced by recurrent febrile seizures
zhi-xian, YANG ; jiong, QIN ; dingfang, BU ; junbao, DU ; zhi xing, CHANG ; ying, HAN
Journal of Applied Clinical Pediatrics 2004;0(12):-
Objective To explore the changing regularity of nitric oxide synthase(nNOS) in recurrent febrile seizures (FS), and the influence of NOS/NO on brain damage induced by recurrent FS.Methods FS rats were induced in a bath of warm water.The ex-periments were divided into 2 groups. The contents of nNOS cDNA in the first group was measured by quantitative RT-PCR and the contents of nNOS protein was measured by Western blot.The mtensity , latency, duration and rectal temperature of the seizure in rats in the second group were recorded. Morphologic changes of hippocampal neurons were observed with HE stain.Results Alter recur-rent FS, the expression of nNOS mRNA in hippocampus was significantly inereased compared with those in control group and hyper-thermia group, associated with an increase of nNOS protein.With the increase of seizure number,thert were changes of seizure latency and gradually prolonged trend of the seizure duration. By using the inhibitor of NOS, the seizure latency was gradually prolonged and the prolonged trend of the seizure duration was significantly decreased than that in FS group.There was no significantly difference of seizure intensity and rectal temperature between 2 groups.After recurrent FS, histological changes of hippocampal neurons could be seen under light microscope.The inhibitor alleviated nearonal injury.Conclusions Recurrent FS can induce nNOS gent expression.The NOS/NO system may be involved in the development of brain damage induced recurrent FS.
7.Expression of the partial protein encoded by mutated COL4A5 gene and analysis of the structure by circular dichroism
Yunfeng WANG ; Jie DING ; Dingfang BU ; Fang WANG ;
Journal of Peking University(Health Sciences) 2004;0(02):-
T mutation resulting in p.G1015V from an X linked Alport patient, and that of corresponding cDNA from a control were expressed in E.coli. The recombinant and mutant polypeptide was a fragment of COL4A5 , containing 158 amino acid residues with a glycine to valine substitution mutation in it. The secondary structure of the two recombinant proteins was analyzed using circular dichroism(CD) spectroscopy. Results: CD spectra of the control exhibited a negative peak near 200 nm whereas that of the patient exhibited a negative peak near 220 nm. The magnitude of the negative peak of the patient decreased as compared with that of the control. Furthermore, secondary structure of the control polypeptide was mainly composed of ? sheet and random coil without ? helix, whereas that of the patient presented 12.9% ? helix. Conclusion: Not only local structure of the substitution site but also folding kinetics of the entire ?5 chain may be changed due to Gly→Val substitution in Alport syndrome. We speculate that the abnormally folded polypeptide chain may not be assembled into the triple helix and the network of type Ⅳ collagen, or may be assembled into loosen triple helix then degraded easily, resulting in the pathognomonic ultrastructural changes of the glomerular basement membrane.
8.Expression of chemokine-like factor 2 (CKLF2) mRNA in the rat myocardium after myocardial infarction
Yanjun GONG ; Tao HONG ; Jie JIANG ; Xue YU ; Dingfang BU ; Yong HUO ; We GAO
Journal of Peking University(Health Sciences) 2003;0(04):-
Objective: To investigate the expression of chemokine like factor 2 (CKLF2) mRNA in the rat myocardium after myocardial infarction(MI).Methods: In a rat model of MI, the myocardium surrounding the infarcted area was used for RNA preparation at different time points. After RT, competitive polymerase chain reaction amplification was performed to assess the expression of rCKLF2 mRNA. SAS Kruskal Wallis test was used for statistical comparisons. Results: The gene expression of rCKLF2 at mRNA level was significantly increased in the myocardium surrounding the infarcted area 3 days, 1 week, 2 weeks after infarction.Conclusion: It is possible that CKLF2 contributes to the pathophysiological process and needs to be further investigated.
9.Study on gene mutation in 11 Chinese families with Hailey-Hailey disease
Hang LI ; Xiukun SUN ; Dingfang BU ; Xuejun ZHU
Journal of Peking University(Health Sciences) 2003;0(04):-
Objective: To screen and identify gene mutations of 11 Chinese patients with Hailey Hailey disease (HHD). Methods: Cases of HHD were diagnosed by history, clinical menifestations and pathology. Then genomic DNA samples of patients were extracted from perpheral blood leukocytes, and polymerase chain reaction(PCR), DNA sequencing were performed. Results: We found five mutations in ATP2C1 gene including 3 nonsense mutations and 2 splicing mutations. Four of them were novel mutations. Conclusion: Both nonsense mutation and splicing mutation could affect the rusult of transcription,translation, and the functions of protein encoded by ATP2C1 gene, so the mutations reported in this study is the underlying cause of HHD.
10.Immunoglobulin variable region gene rearrangement and hypermutation in paraneoplastic pemphigus associated Castleman’s tumor
Jing WANG ; Dingfang BU ; Xuejun ZHU
Journal of Peking University(Health Sciences) 2003;0(05):-
Objective: We have studied the role of lymphoproliferative tumors in the pathogenesis of autoimmune and the origin of the autoantibodies in paraneoplastic pemphigus (PNP) in recent years. A Castleman’s tumor from a patient was identified to produce autoantibody. To identify the relationship between the tumor and pathogenesis of the disease, we analyzed the rearrangement of immunoglobulin variable region gene and its hypermutation in B cells of Castleman’s tumor from a patient who was diagnosed of paraneoplastic pemphigus. Methods: The surface-markers of cultured tumor lymphocytes were assessed with immunochemistry staining. After total RNA of the tumor cells were isolated, the mRNA was reversely transcribed into cDNA. V H and V L genes were cloned and their sequences were analyzed. Results: Immunochemistry staining and flow cytometer analysis showed that the tumor cells were CD20, HLA-DR, smIgM, and smIgG positive. The cloned IgV H and IGHV3-9*01 germ-line gene are homologous and so are the Ig V L and the IGKV4-1*01 germ-line gene. More nucleotide changes in the V H or V L occurred in CDRs than those in FRs. Conclusion: In this reported case, a clone of specific B-lymphocyte in the Castleman’s tumor carrying functional rearranged immunoglobulin heavy and light chain genes was found to have experienced switch recombination and was possible to produce IgG autoantibody.

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