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<p><b>OBJECTIVE</b>To analyze a fetus with abnormal cardiac ultrasound by using various techniques and explore its genotype-phenotype correlation.</p><p><b>METHODS</b>Lymphocytes derived from umbilical cord blood sample were subjected to G-banding analysis. Short tandem repeats quantitative fluorescence PCR (STR-QF-PCR) was used for analysis of fetal DNA as an auxiliary test. Low-coverage whole genome sequencing (WGS) was used to detect chromosomal deletion/duplication which exceeded 100 kb in size.</p><p><b>RESULTS</b>The karyotype of the fetus was 47,XN,+mar. As detected by STR-QF-PCR, the copy number of GATA178F11 locus on chromosome 18 was 4, and the duplicated fragment was derived from the mother. WGS suggested that the fetus to be 46,XN,dup(18p11.21p11.32).seq [GRCh37/hg19](10 001-15 378 887)× 4, with the duplicated fragment spanning approximately 15.38 Mb.</p><p><b>CONCLUSION</b>The cardiac malformation of the fetus may be attributed to the partial duplication of chromosome 18p. Combined cytogenetic and molecular methods can facilitate prenatal detection of genetic abnormalities.</p>
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Objective To evaluate the necessity and feasibility by using two different PCR-based techniques for prenatal diagnosis of thalassemia. Methods 509 specimens for prenatal diagnosis of thalassemia were detected respectively by single tube multiplex PCR(STMP),reverse dot blot(RDB)or probe melting curve assay(PMCA)for commonα-thalassemia orβ-thalassemia mutations in double-blind tests. Samples with different detection results were confirmed with DNA sequencing analysis. Prenatal diagnosis of thalassemia results were verified or followed up after birth. Results In detectingα-thalassemia andβ-thalassemia,there was one case in STMP + RDB and another case PMCA indicating differentiating results. The detection sensitivity of STMP + RDB was higher than that of PMCA,and its difference can be used as an indication for maternal blood contamination. Conclusion The two PCR methods with different principles were necessary and feasible for the prenatal diagnosis of thalassemia. The two methods were complementary to each other ,which can ensure the reliability of the prenatal diagnosis results and reduce the defects of single technique. It is worthy to be popularized in clinical application.
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Objective To investigate the clinical value of the probe melting curve analysis‐based PCR assay for the detection of three types of αT .Methods A total of 149 blood and prenatal archival DNA samples (6 of which were amniotic fluid samples)with three knownαT genes ,which included 63 carriers with Hb CS ,22 cases with Hb QS ,43 individuals with Hb WS and 1 double heter‐ozygote with Hb CS and Hb WS) as well as 20 samples with normalα‐globin gene sequence that had been confirmed by RBD com‐bined with DNA sequencing were selected to test the specificity of probe melting curve analysis by blind analysis .Results The probe melting curve analysis accurately detected 100 of the DNA samples previously characterized by S RBD combined with DNA sequencing .Conclusion Probe melting curve analysis‐based PCR assay for the detection ofαT is featured with rapidity and accuracy and can be applied to clinical and prenatal diagnosis .
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Objective To study the generation of metallo-β-lactamase(MBLs) and its related gene carrying situation in the clini-cal isolates of Pseudomonas aeruginosa .Methods Ceftazidime and imipenem were adopted to preliminarily screen MBLs of Pseudo-monas aeruginosa .The phenotypic confirmatory of imipenem-resistant and ceftazidime-resistant Pseudomonas aeruginosa was per-formed by using 2-mercaptopropionic acid (2-MPA) or EDTA synergy test and the MBLs genotypes of the positive strains in the preliminary screen were detected by PCR .Results The positive rate of the MBLs preliminary screen test in multi-resistant strains was 10 .9% ,and the positive rate of the MBLs in multi-resistant strains detected by CAZ/EDTA ,CAZ/2-MPA ,IMP/EDTA and IMP/2-MPA was 7 .5% ,7 .9% ,8 .8% and 9 .5% respectively .The positive rates of ipm1 and vim gene by PCR were 10 .4% and 8 .3% respectively .The strains with positive spm ,sim1 and gim were not found .Conclusion The MBLs test results detected by different methods are different ;MBLs genes carying ipm1 and vim are the main reason for carbapenem-resistant multi-drug resist-ant Pseudomonas aeruginosa in the hospital .
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Objective To compare the reliability of erythrocyte parameter mean corpuscular volume(MCV)and mean corpuscu-lar hemoglobin(MCH)for screening thalassaemia trait.Methods A fresh venous blood sample with the cut-off value of MCV was sent to 21 hospitals of Zhuhai city for conduct the full blood cell analysis within 1 d.Then the inter-and intra-coefficient of varia-tion (CV)as well as bias values of MCV and MCH were calculated and compared.In addition,10 EDTA-anticoagulant venous blood samples were divided into two parts,the effects of stored temperature and time on MCV and MCH were observed.Results The coefficient of variation(CV)of MCV (4.1%)was significantly greater than that of MCH (2.8%)among 21 laboratories,the qualification rate of MCH detection results was 100%,which was significantly higher than 66.7% of MCV (P 0.05).When these samples were stored under the refrigerated condition for 72 h,MCV had no statistically sig-nificant difference compared with the instant detection results of MCV (P >0.05),when stored at the room temperature for 48 h, MCV was significantly increased (P <0.05),MCV had statistical difference in storage for 48 h between the room temperature and the refrigeration.Conclusion Among laboratories and under different temperature conditions,the reproducibility of MCH is better than that of MCV and is more stable than MCV.MCH as the clinical first-line screening for thalassaemia is more reliable than MCV.
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ObjectiveTo evaluate the reliability of the probe melting curve analysis (PMCA) based on real-time fluorescent PCR assay for the genetic diagnosis and prenatal diagnosis of β-thalassemia.MethodsA total of 135 cases of peripheral blood samples were collected from Zhuhai Municipal Maternity and Child Healthcare Hospital between 2008 and 2010.All the samples were performed preliminary diagnosis according to the hematological data.Of these,119 cases were diagnosed as β-thalassemia trait,4 cases were diagnosed as severe thalassemia and 12 cases were normal.In addition,44 cases of amniotic fluid and 8 cases of cord blood with high-risk for severe β-thalassemia were also collected.The diagnostic reliability of the PMCA assay and reverse dot blot assay was evaluated on 187 above-mentioned cases by direct DNA sequencing analysis in a double-blind study.ResultsThe genotypes of 185 cases were detected accurately based on the PMCA assay except for two cases:one heterozygote with Ini( ATG ＞ AGG) was omitted and another heterozygote couldn't be distinguished between CD43 ( G ＞ T) and CD37 ( G ＞ A ).For the RDB assay,only one heterozygote with CD71-72 ( + T) was not detected accurately in the above-mentioned cases.Compared with the DNA sequencing analysis,the sensitivity,specificity,negative predictive value,positive predictive value and diagnostic efficiency of the PMCA assay were 98.75％,100.00％,93.10％,100.00％ and 98.93％,respectively.The corresponding value of the RDB assay were 99.38％,100.00％,96.42％,100.00％ and 99.47％,respectively.There were no significant between-group differences in the diagnostic efficiency of the two assays ( P ＞ 0.05 ).The results of prenatal diagnosis were in complete concordance with the follow up results,after the birth or induced labour of the fetuses.ConclusionsThe PMCA assay can be used as an alternative and verified method of RDB assay for the genetic diagnosis and prenatal diagnosis of β-thalassemia.
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Objective To investigate the correlation between the erythrocyte indices and the genotypes of alpha thalassemia.Methods337 carriers with various genotypes of alpha-thalassaemia ( iron deficiency,alpha-thalassemia double heterozygote and homozygote,α-compounding β-thalassemia and abnormal hemoglobinopathy were excluded) were classified into three groups based on different genotypes of alpha-thalassaemia including silent thalassemia group (ST,83 cases),α-thalassemia trait group (TT,210cases) and intermediate thalassemia group( IT,44 cases),and 154 healthy adults were randomly choosed as normal control The erythrocyte indices involving in RBC,Hb,MCV,MCH,MCHC and RDW-CV were retrospectively analyzed and the difference of which was compared by analysis of variance and SNK test among aboved-mentioned groups.ResultsThere were statistical significance among groups about erythrocyte indices except Hb F.The order of the level of MCV and MCH was NC [( 86.6 ± 5.2) fl,( 29.5 ± 2.1 ) pg] ＞ST[(80.1 ±3.3) fl,(26.7±1.3) pg] ＞TT[(68.5 ±3.4) fl,(22.0 ±1.2) pg] ＞IT[(66.6±7.1)fl,(20.0 ±2.2) pg,F =580.67,761.19,P ＜0.05].And the size of RDW-CV was IT(22.3 ±3.4)％ ＞TT (14.9±1.2) ％ ＞ST(13.8±1.6)％ ＞NC(13.2±1.4)％(F=347.25,P＜0.05).In ST group,the value of MCHC of -α3.7/αα subgroup( 335.6 ± 8.0) g/L was higher than that of -α4.2/αα subgroup( 330 ±7.2) g/L and αTα/αα subgroup (328.4 ±9.5) g/L(F=6.07,P ＜0.05).Meanwhile,in IT group,the value of MCV of αTα/--SEA subgroup( 70.1 ± 7.2 ) fl was higher than that of -α3.7/--SEA subgroup ( 63.4 ±5.9) fl and -α4.2/--SEA subgroup ( 64.1 ± 4.0 ) fl ( F =5.55,P ＜ 0.05 ).However,the value of MCHC of αTα/--SEA subgroup( 289.7 ± 21.2 ) g/L was lower than that of other two subgroups [( 306.3 ± 8.4 ),(306.1 ± 8.7) g/L,F =8.72,P ＜0.05].Except Hb A2 and Hb F,there was positive correlation between the number of deleted α-globin gene and that of RBC and RDW-CV ( r =0.318 and 0.580,P ＜0.01 ).Nevertheless,there was negative correlation between the number of deleted α-globin gene and that of the other erythrocyte indices (r =-0.483,-0.827,-0.744 and -0.684,P all ＜0.01 ).ConclusionsThere is close correlation between the degree of anemia and the number of deleted α-globin gene characterized by Hb reduction and RBC increasing.In addition,the anemia degree of non-deletional Hb H disease is severer than that of deletional Hb H,which of Hb H disease with -α4.2/--SEA is severer than that with -α3.7/--SEA.
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ObjectiveTo report the results of preventive control program of severe thalassemias in Zhuhai City of Guangdong Province from 1998 to 2010.MethodsAs the guide centre of marriage and childbearing and the greatest maternity hospital in Zhuhai City of Guangdong Province,Zhuhai Municipal Maternity and Child Healthcare Hospital constructed the genetic screening network for thalassemias testing and referred for follow-up and for genetic counseling.The couples for premarital medical examination or regular healthcare examination in pregnancy were enrolled to this preventive control program.A conventional strategy of screening for heterozygote was used to identify the α- and β-thalassemia traits in women and their spouses according to the standard procedures of hematological phenotype analysis which was recommended by Thalassemia International Federation (T IF).Then those suspected couples at risk were diagnosed for α- and β-thalassemia by PCR-based DNA assays.The couples at risk for severe thalassemias were counseled and offered prenatal diagnosis and termination of pregnancy in case of an affected fetus in the rights of consent and of option voluntarily.ResultsFrom January 1998 to December 2010,85 522 brides and grooms-to-be for premarital screening and 41 503 pregnant women in addition to 14 141 partners for prenatal screening were recorded,the covering rates of premarital screening and prenatal screening in the city were 92.698％ (from 1998 to 2003) and 27.667％ (from 2004 to 2010),respectively.Totally 10 726 cases were found to be the carriers of thalassemias,with 7393 for o-thalassemia (5.237％,7 393/141 166) and 3333 for β-thalassemia (2.361％,3 333/141 166).A total of 257 couples at-risk for severe thalassemias were detected including 190 for α-thalassemia and 67 for β-thalassemia.Among them,251 (97.7％,251/257) couples were performed prenatal diagnosis.During the preventive control program,a total of 72 fetuses with severe thalassemias including hemoglobin H disease were voluntarily terminated.In Zhuhai City,the average annual birth rate of fetuses with severe thalassemia was declined by 32.9％ (49/149).ConclusionsThis study has reduced effectively birth rate of perinatal infants with severe thalassemias in Zhuhai City by genetic screening and prenatal diagnosis of thalassemia in the large population of 13 years.Our summary comes out of technical proposals for prenatal screening and diagnosis,which could be take example by preventative control of thalassemia in other regions of China where are prevalent.