Prenatal diagnosis of pyruvate dehydrogenase E1-α deficiency: a case report / 中华围产医学杂志

This article reported a case of pyruvate dehydrogenase E1-α deficiency suggested by abnormal brain development during prenatal ultrasound imaging. Prenatal ultrasound revealed a mild enlargement of bilateral cerebral ventricles and the possibility of intracranial hemorrhage in the fetus at 25 +1 weeks of gestation. MRI showed the fetus with absent corpus callosum, enlarged bilateral cerebral ventricles and paraventricular cysts. After genetic counseling and careful consideration, the couple opted for pregnancy termination. To clarify the cause of the disease, whole-exome sequencing was performed on the fetal skin to detect possible variants, and which revealed a frameshift mutation c.924_930dup(p.R311Gfs*5) in exon 10 of the PDHA1 gene. Sanger sequencing confirmed the mutation was a de novo pathogenic variant, indicating that the fetus was affected by pyruvate dehydrogenase E1-α deficiency.

Analysis of follow-up information and pregnancy outcomes of cell free DNA prenatal screening / 中华妇产科杂志

Objective:To evaluate the efficacy of cell free DNA (cf-DNA) screening in prenatal care by analyzing the follow-up information and pregnancy outcomes.Methods:All cf-DNA cases conducted in Women′s Hospital of Nanjing Medical University from August 2011 to December 2017 were enrolled. The general information of the pregnancies, cf-DNA results, confirmatory testing results, and the follow-up results were collected. The pregnancy outcomes were analyzed in cases with low risk cf-DNA results as well as with high risk results for common trisomies, which were trisomy 21 (T21), trisomy 18 (T18), and trisomy 13 (T13). The sensitivity, specificity, positive predictive value and negative predictive value of cf-DNA screening were calculated.Results:(1) A total of 43 615 cf-DNA cases were involved, with 44 cases (0.10%, 44/43 615) test failure results, 314 cases (0.72%, 314/43 571) high risk results for common trisomies and 43 257 cases (99.27%, 43 257/43 571) low risk results. (2) Among 277 cases (88.21%, 277/314) high risk cases were successfully followed up, and 228 cases (82.31%, 228/277) underwent invasive confirmatory prenatal diagnosis. In the low risk results, 36 826 cases (85.13%, 36 826/43 257) were successfully followed up, and 572 (1.55%, 572/36 826) cases were found to have adverse pregnancy outcomes, among which 4 false negative cf-DNA results were confirmed. (3) In the 37 103 successfully followed up cf-DNA cases, the sensitivity for T21, T18, T13 were calculated as 97.96%, 96.67% and 100.00%, respectively; the specificity for T21, T18, T13 were calculated as 99.96%, 99.95% and 99.95%, respectively. The positive predictive value for T21, T18, T13 were calculated as 90.57%, 63.04% and 17.39%, respectively. The negative predictive value for T21, T18, T13 were calculated as 99.99%, 99.98% and 100.00%.Conclusions:Cf-DNA is effective in detecting common trisomies, with a high sensitivity and specificity. However, the follow-up information revealed several potential limitations in current clinical practice, such as a number of cases with high risk results rejected invasive confirmatory testing, as well as the genetic diagnostic results for most low risk cases with an adverse pregnancy outcome aren′t obtained. Genetic counseling and the follow-up for all the cf-DNA cases should be emphasized in the future.

Analysis of follow-up information and pregnancy outcomes of cell free DNA prenatal screening / 中华妇产科杂志

Objective@#To evaluate the efficacy of cell free DNA (cf-DNA) screening in prenatal care by analyzing the follow-up information and pregnancy outcomes.@*Methods@#All cf-DNA cases conducted in Women′s Hospital of Nanjing Medical University from August 2011 to December 2017 were enrolled. The general information of the pregnancies, cf-DNA results, confirmatory testing results, and the follow-up results were collected. The pregnancy outcomes were analyzed in cases with low risk cf-DNA results as well as with high risk results for common trisomies, which were trisomy 21 (T21), trisomy 18 (T18), and trisomy 13 (T13). The sensitivity, specificity, positive predictive value and negative predictive value of cf-DNA screening were calculated.@*Results@#(1) A total of 43 615 cf-DNA cases were involved, with 44 cases (0.10%, 44/43 615) test failure results, 314 cases (0.72%, 314/43 571) high risk results for common trisomies and 43 257 cases (99.27%, 43 257/43 571) low risk results. (2) Among 277 cases (88.21%, 277/314) high risk cases were successfully followed up, and 228 cases (82.31%, 228/277) underwent invasive confirmatory prenatal diagnosis. In the low risk results, 36 826 cases (85.13%, 36 826/43 257) were successfully followed up, and 572 (1.55%, 572/36 826) cases were found to have adverse pregnancy outcomes, among which 4 false negative cf-DNA results were confirmed. (3) In the 37 103 successfully followed up cf-DNA cases, the sensitivity for T21, T18, T13 were calculated as 97.96%, 96.67% and 100.00%, respectively; the specificity for T21, T18, T13 were calculated as 99.96%, 99.95% and 99.95%, respectively. The positive predictive value for T21, T18, T13 were calculated as 90.57%, 63.04% and 17.39%, respectively. The negative predictive value for T21, T18, T13 were calculated as 99.99%, 99.98% and 100.00%.@*Conclusions@#Cf-DNA is effective in detecting common trisomies, with a high sensitivity and specificity. However, the follow-up information revealed several potential limitations in current clinical practice, such as a number of cases with high risk results rejected invasive confirmatory testing, as well as the genetic diagnostic results for most low risk cases with an adverse pregnancy outcome aren′t obtained. Genetic counseling and the follow-up for all the cf-DNA cases should be emphasized in the future.

Clinical report of testicular hypoplasia combined with 21-hydroxylase deficiency / 中华医学遗传学杂志

OBJECTIVE To investigate the correlation of 21-hydroxylase deficiency (21-OHD) with male testicular dysplasia. METHODS Clinical data of 8 infertile males with congenital adrenal hyperplasia due to 21-OHD was retrospectively analyzed. In addition, potential mutations of the CYP21A2 gene was detected. RESULTS All patients were referred because of azoospermia or severe oligospermia and had small testis with averaged testicular volume of 6.1 mL. Three patients had testicular adrenal rest tumors. Endocrinologic examinations revealed low levels of leutinizing hormone and follicular stimulating hormone, normal or elevated testosterone, elevated progesterone, elevated or normal adrenocoticotropic hormone, and low or normal cortisol. All patients had adrenal cortical hyperplasia, 5 with adrenal adenoma, 1 case associated with bilateral adrenal myelolipoma. All patients were given glucocorticoid replacement therapy for 3 to 6 months, which successfully improved the seminal status of 6 patient and resulted pregnancies in 5 couples. Seven pathogenic mutations of the CYP21A2 gene among the 8 patients. CONCLUSION 21-OHD can cause testicular hypoplasia and spermatogenic failure. Glucocorticoids and operations can obtain good result and improve spermatogenesis. Our results have shown a good genotype/phenotype correlation in these cases. All patients have carried the p.Ile172Asn mutation, which is associated with simple virilizing form.

Genetic analysis and prenatal diagnosis for 25 Chinese pedigrees affected with congenital adrenal hyperplasia due to 21-hydroxylase deficiency / 中华医学遗传学杂志

OBJECTIVE@#To identify pathogenic mutations in 25 Chinese pedigrees affected with congenital adrenal hyperplasia (CAH).@*METHODS@#Mutations of the CYP21A2 gene were detected with locus-specific PCR/restriction endonuclease analysis, multiplex ligation-dependent probe amplification assay, and direct sequencing of the entire CYP21A2 gene. Prenatal diagnosis was offered to fetuses at risk for CAH.@*RESULTS@#All 50 alleles of the CYP21A2 gene carried by the 25 pedigrees were successfully delineated. Large deletions and conversions have accounted for 16 (32%) of the alleles, which included 9 entire CYP21A2 gene deletions, 6 chimeric CYP21A1P/CYP21A2 genes, and 1 partial conversion of the CYP21A2 gene. For the remaining 34 alleles, there were 9 micro-conversions and 4 de novo mutations [including a previously unreported c.62G>A (p.Trp21X) mutation]. Prenatal diagnosis was provided for 28 fetuses with a high risk for CAH, among whom 8 were found to be affected.@*CONCLUSION@#The detection of CYP21A2 gene mutations can facilitate appropriate genetic counseling and prenatal diagnosis for the affected pedigrees.

Prenatal diagnosis for Walker-Warburg syndrome by whole exome sequencing / 临床检验杂志

Objective To perform prenatal diagnosis for a fetus with hydrocephalus and congenital heart disease by whole exome se-quencing ( WES) , and then provide genetic counseling for the next pregnancy. Methods DNAs from amniotic fluid cells of the fetus and peripheral blood of his/her parents were extracted, respectively, and then performed WES. After the process of library construc-tion, hybrid capture and sequencing, the obtained data were compared with the database from human genome and literatures and ana-lyzed by software. The pathogenic mutations were searched based on the American College of Medical Genetics and Genomics ( ACMG, 2015) guideline and verified by the Sanger sequencing. Results The WES results found that the compound heterozygous mutations ex-isted in POMT1 gene of the fetus, which were inherited from the splice site mutation c.605+1G>A( IVS7) of his/her mother and the frameshift mutation c.1367 c.1368 ( exon 15) insGA, p. L456Lfs?80 of his/her father, respectively. The Sanger sequencing results were consistent with that of WES. The fetus was affected by Walker-Warburg syndrome, and his/her parents decided to terminate the pregnancy finally. Conclusion The WES may diagnose Walker-Warburg syndrome rapidly and accurately, which may play an impor-tant role in clinical management and genetic counseling.

Construction of model for cardiomyocyte disease MERRF using patient-derived iPSC / 临床检验杂志

Objective To obtain myoclonic epilepsy with ragged-red fibers (MERRF)-specific cardiomyocytes by the differentiation in vitro of inducing pluripotent stem cells (iPSC) derived from a MERRF patient and evaluate the application of the prepared cardiomyocytes in construction of MERRF syndrome model.Methods The patient-derived iPSCs and H9 embryonic stem (ES) cells,the control cell line,were unidirectionally differentiated into cardiomyocytes n in vitro.The obtained cardiomyocytes were identified and validated by detecting the presence of cardiomyocyte-specific markers using immunofluorescence staining and RT-PCR.The beating frequencies were recorded to compare the functional evaluation for the two groups of cardiomyocyte.Results Both the patient-derived iPSC and H9 ES cells were differentiated into cardiomyocytes successfully.The average beating frequencies of MERRF-induced cardiomyocytes (iCMs) were 13,24,15 and 18 times/min on the day 10,13,15 and 16 during the cell differentiation process.The average beating frequencies of H9-iCMs were 80,96,120 and 120 times/min,respectively.The beating ability of iPSC-differentiated cardiomyocytes was significantly lower than that of corresponding control (all P ＜ 0.05).Conclusion The patient-derived iPSCs may differentiated into cardiomyocytes.Based on the functional evaluation for these cardiomyocytes,the model for MERRF syndrome with mitochondrial mutations was generated and characterized in vitro.

Bundles of care prevents postoperative delirium in elderly patients with hip fractures / 中华创伤杂志

Objective To evaluate the effect of bundles of care on the prevention of postoperative delirium among elderly patients with hip fractures.Methods A prospective randomized case control study was conducted on 80 patients (≥65 years old) with hip fractures from March 2017 to June 2017.The patients were divided into experimental group (n =43) and control group (n =37) according to the random number table method.The experimental group received bundles of care,while the control group received routine nursing.The patients in both groups were all surgically treated,and the confusion assessment method (CAM) was applied to diagnose delirium after surgery.Gender,age,fracture type,duration from injury to operation,internal fixation type,operation time,total amount of bleeding,visual analogue scale (VAS),incidence of delirium,complications,and adverse events were compared between the two groups.Results Among the 80 patients,there were 11 males and 69 females,aged averagely 79.3 years (range,65-95 years).No significant differences were found between experiment group and control group in terms of gender (male:6 cases vs.5 cases,females:37 cases vs.32 cases),age [(79.8 ± 7.8) years vs.(78.7 ± 8.9) years],cause of injury (traffic injuries:7 cases vs.4 cases;falling injuries:36 cases vs.33 cases),duration from injury to operation [(66.1 ±14.3)hours vs.(63.4 ±14.9) hours],fracture type (femoral neck:13 cases vs.10 cases;intertrochanteric:26 cases vs.24 cases;subtrochanteric:4 cases vs.3 cases),internal fixation type (artificial total hip:5 cases vs.5 cases;artificial femoral head:8 cases vs.5 cases;PFNA:29 cases vs.27 cases),operation time [(55.5 ± 16.8) minutes vs.(51.6 ± 17.0) minutes],total blood loss [(114.4 ± 73.9) ml vs.(108.1 ±72.0) ml] (P ＞ 0.05).After bundles of care intervention,the postoperative VAS [(2.2 ± 0.8) points vs.(4.3 ± 1.2) points],postoperative delirium incidence (9％ vs.32％),incidence of complications and adverse events (2％ vs.19％) in experimental group were significantly lower than those in control group (P ＜ 0.05).Conclusion Bundles of care can relieve the pain and effectively reduce the incidences of postoperative delirium,complications,and adverse events in elderly patients with hip fracture.

Prenatal diagnosis of two fetuses with chromosome 1p36 deletion syndrome / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze two fetuses with multiple malformations revealed by ultrasonography using single nucleotide polymorphism array (SNP array), and to explore the strategy for the prenatal diagnosis of 1p36 deletion syndrome.</p><p><b>METHODS</b>Amniocentesis was performed on the two pregnant women. Amnion fluid cells were cultured, and karyotypes of the fetuses were determined through G-banding analysis. Whole genome SNP array was used to detect genomic anomalies of the two fetuses. The karyotypes of their parents were determined through G-banding analysis of peripheral venous blood samples.</p><p><b>RESULTS</b>G-banding analysis showed a 46,XY,add(1p36)? and a 46,XX,add(1p36)? karyotype for fetuses 1 and 2, respectively. SNP array analysis showed that the fetus 1 had arr[19]1p36.33p36.32 (752 566 - 3 393 462)×1 and 7q35q36.3 (144 480 549 - 159 119 486)×3, and fetus 2 had arr[19]1p36.33p36.23 (752 566 - 8 362 754)×1, 6p25.3p22.3 (204 909 - 20 182 185)×3. The mother of fetus 1 had a 46,XX,t(1;7)(p36;q35) karyotype, and the mother of fetus 2 had a 46,XX,t(1;6)(p36;p22) karyotype. The karyotypes of both fathers appeared to be normal.</p><p><b>CONCLUSION</b>SNP array has the advantages such as high sensitivity and high accuracy for prenatal diagnosis, and can provide more detailed information for genetic counseling of 1p36 deletion syndrome.</p>

Detection of TSC1/TSC2 gene mutations among patients with tuberous sclerosis complex by Ion Torrent semiconductor sequencing / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To develop and validate a method for mutation screening and prenatal diagnosis of TSC1/TSC2 mutations among patients with tuberous sclerosis complex (TSC) by Ion Torrent semiconductor sequencing.</p><p><b>METHODS</b>Potential mutations of SC1/TSC2 gene was detected in 2 TSC families and 1 sporadic TSC patient using an Ion Torrent PGM sequencer. Candidate variants were validated by Sanger sequencing. The corresponding site of TSC2 in the fetus of family 2 was also detected with Sanger sequencing.</p><p><b>RESULTS</b>Ion Torrent semiconductor sequencing has identified a probably pathogenic TSC2 mutation (c.311-312insGCTG) in the patient from family 1, and a probably pathogenic TSC2 mutation (c.1790A>G) in the patient of family 2.</p><p><b>CONCLUSION</b>Targeted Ion Torrent PGM sequencing is an accurate and efficient method to detect TSC1/TSC2 mutations in TSC.</p>

Mutation screening and prenatal diagnosis of methylmalonic academia in a Chinese pedigree by Ion Torrent semiconductor sequencing / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To identify pathogenic mutations in a Chinese pedigree affected with methylmalonic academia for genetic counseling and prenatal diagnosis.</p><p><b>METHODS</b>Molecular analysis of the MUT, MMACHC, MMAA and MMAB genes was performed for the proband with methylmalonic academia by Ion Torrent semiconductor sequencing. Candidate mutations were validated by Sanger sequencing. The couple was offered prenatal diagnosis via analyzing of the fetal DNA through amniocentesis.</p><p><b>RESULTS</b>The proband was found to be compound heterozygous for c.609G>A (p.Trp203X) and c.658-660del AAG (p.Lys220del) mutations, which were inherited respectively from each of his parents. Prenatal diagnosis showed that the fetus has inherited two wild-type parental alleles.</p><p><b>CONCLUSION</b>The targeted Ion Torrent PGM sequencing has detected pathogenic mutations in the Chinese pedigree affected with methylmalonic academia, which has provided molecular evidence for clinical diagnosis, genetic counseling and prenatal diagnosis for the family.</p>

Development and application of molecular diagnostic method of hemophilia A / 中华检验医学杂志

Objective To develop and validate a method for detecting factor 8 gene (F8) mutations in hemophilia A patients by Ion Torrent semiconductor sequencing .Methods Intron 22 and intron 1 inversions of F8 gene were identified by long distance PCR (LD-PCR), other mutations in the F8 gene were identified by Ion Torrent sequencing.Candidate variants were validated by Sanger sequencing .Sanger sequencing was applied to screen HA carriers from 11 female family members in the 8 pedigrees.One pregnant woman was offered prenatal diagnosis via analyzing the fetal DNA obtained through amniocentesis . Results Four missense mutations ( c.1331A >C, 1648C >T, c.6506G >A, c.6544C >T), two frameshift mutations ( c.2393 _2394insT, c.6320delG), one splicing mutation ( IVS5 +5G >A), one nonsense mutation (c.43C >T) and one Inv22 mutation were identified in all nine probands respectively . Among 11 female family members, 10 females were identified to be HA carriers, and one didn′t carry the maternal pathogenic mutation.Prenatal diagnosis result showed that the fetus inherited the wild -type maternal allele and was predicted to be unaffected by HA .Conclusion The targeted Ion Torrent sequencing is a reliable and efficient method to detect F8 mutations in patients with Hemophilia A disease .

Detection of pathogenic mutations for methylmalonic acidemia using new-generation semiconductor targeted sequencing / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To detect the pathogenic mutation in a patient with methylmalonic acidemia using IonTorrent Personal Genome Machine (PGM) and assess the feasibility of such technology for analyzing complex monogenic diseases.</p><p><b>METHODS</b>Peripheral blood sample was collected from the patient. Genomic DNA was isolated using a standard method and subjected to targeted sequencing using an Ion Ampliseq Inherited Disease Panel. DNA fragment was ligated with a barcoded sequencing adaptor. Template preparation, emulsion PCR, and Ion Sphere Particles enrichment were carried out using the Ion One Touch system. Data from the PGM runs were processed using Ion Torrent Suite 3.2 software to generate sequence reads. All variants were filtered against dbSNPl37. DNA sequences were visualized with an Integrated Genomics Viewer.</p><p><b>RESULTS</b>After data analysis and database filtering, a previously reported nonsense mutation, c.586C>T (p.R196X), and a novel mutation c.898C>T (p.R300X) were identified in the MMAA gene in this patient. Both mutations were verified by conventional Sanger sequencing.</p><p><b>CONCLUSION</b>Pathogenic MMAA mutations have been identified in a patient with methylmalonic acidemia. This new-generation targeted sequencing on the PGM sequencers can be applied for genetic diagnosis of hereditary diseases.</p>

Application of multiplex ligation-dependent probe amplification for rapid detection of aneuploidies and structural chromosomal abnormalities in prenatal diagnosis / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the value of multiplex ligation-dependent probe amplification (MLPA) for rapid detection of aneuploidies and structural chromosomal abnormalities during prenatal diagnosis.</p><p><b>METHODS</b>Two hundred and eight six amniotic fluid samples were analyzed with both MLPA and conventional karyotyping. Structural abnormalities were verified with array comparative genomic hybridization.</p><p><b>RESULTS</b>Ten cases of trisomy 21, 2 cases of trisomy 18, 1 case of trisomy 13, 1 case of mosaic trisomy 21, 1 case of 45,X, 1 case of large deletion of Xp, 1 case of trisomy 18p and 1 case of large deletion of 18p and 18q were identified. The same results were derived by both MLPA and conventional karyotyping. Structural abnormalities were verified by array comparative genomic hybridization (aCGH) with 100% accuracy.</p><p><b>CONCLUSION</b>In addition to aneuploidies, MLPA can rapidly identify large deletions and duplications of chromosomes 21, 18, 13, X and Y. MLPA is supplementary to conventional karyotyping for identification of such chromosomal abnormalities prenatal diagnosis.</p>

Array comparative genomic hybridization detection of a de novo 4q21.21-q22.1 deletion in a child with severe growth retardation / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze a child with developmental delay, severe mental retardation, speech delay and muscular hypotonia.</p><p><b>METHODS</b>The karotypes of the child and her parents were analyzed with G-banding analysis. Their genome DNA was also analyzed with array comparative genomic hybridization (array-CGH).</p><p><b>RESULTS</b>No karyotypic abnormality was detected at cytogenetic level. However, array-CGH has identified a de novo 4q21.21-q22.1 deletion in the child, which has a size of 12.1 Mb.</p><p><b>CONCLUSION</b>The de novo interstitial 4q21.21-q22.1 deletion probably underlies the main clinical manifestation in the child. Array-CGH is useful for diagnosing children with multiple congenital anomalies with unclear etiology.</p>

Value of orthopedic POSSUM and P-POSSUM scoring system in predicting operation risk in aged patients with hip fracture / 中华创伤杂志

Objective To measure the value of orthopedic physiological and operative severity score for the enumeration of mortality and morbidity (POSSUM) and Portsmouth modified POSSUM (P-POSSUM) scoring systems in predicting operative risks in aged hip fracture patients.Methods Orthopedic POSSUM and P-POSSUM were performed to predict complication incidence and mortality for 164 aged patients operated for hip fracture.Validation of the scoring systems was tested by assessing observed to expected ratio,discrimination,and calibration.Discriminative ability and calibration of both scores were estimated using receiver operation characteristic curve (ROC) and Hosmer-Lemeshow test respectively.Results Orthopedic POSSUM score performed in predicting incidence of postoperative complications showed overall observed to expected ratio of 0.86,area under the curve of 0.82,and good calibration (H2 =3.66,df=8,P ＞ 0.05).P-POSSUM performed in predicting mortality showed overall observed to expected ratio of 0.80,area under the curve of 0.93 and good calibration (H2 =3.21,df =4,P ＞ 0.05).While orthopedic POSSUM overestimated postoperative mortality (overall observed to expected ratio =0.27).Conclusion Orthopedic POSSUM and P-POSSUM scores are respectively accurate in predicting postoperative complication incidence and mortality in aged hip fracture patients,but orthopedic POSSUM score overestimates the mortality.

Correlation between CYP21A2 genotype and phenotype in patients with 21-hydroxylase deficiency / 临床儿科杂志

Objectives To study the mutation spectrum in CYP21A2 gene in patients with 21-hydroxylase deficiency (21-OHD), and to analyze the relationship between genotype and phenotype. Methods Eighteen patients with 21-OHD were identified by neonatal screening of 17α-OH progesterone (17α-OHP). The allele specific PCR-DNA sequencing com-bining with multiplex ligation-dependent probe amplification was applied to determine the genotype in the patients and their parents. Results Six mutations of CYP21A2 gene were identified. I2G (44.4%) and del (33.3%) were the most frequent mutations and also were the most common mutations in salt-wasting form. The detection rate of I172N mutation in simple virilizing form was 75%. Patients were classified into three groups according to the degree of 21-hydroxylase enzymatic compromise caused by the mutation. The serum 17α-OHP, ACTH and T levels which reflected the severity of disease were significantly different among three groups (P<0.05). Conclusions The genetic diagnosis of 21-OHD reveals the consistency between genotype and phenotype.

Detection of cryptic copy number variations in a fetus with congenital heart disease by array-based comparative genomic hybridization / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To detect the copy number variation (CNV) of a fetus with interrupted aortic arch and ventricular septal defect, in order to explore the underlying genetic causes of the congenital malformation, and investigate the feasibility of array-based comparative genomic hybridization (array-CGH) in molecular cytogenetic diagnosis.</p><p><b>METHODS</b>The whole genome of the fetus with de novo apparently balanced translocations [46,XX,t(7;9)(q12;q21)] diagnosed by G-banding was scanned and analyzed by array-CGH, and the copy number variation was confirmed by fluorescence in situ hybridization (FISH).</p><p><b>RESULTS</b>A pathologic submicroscopic CNV [del(22) (q11.2) (17 370 128-19 790 009, -2.42 Mb)] was identified and mapped by array-CGH. FISH test confirmed the microdeletion detected by array-CGH.</p><p><b>CONCLUSION</b>The cryptic 22q11.2 deletion might be the reason leading to the congenital malformation of the fetus. This study provides evidence that apparently balanced translocations classified by conventional cytogenetic techniques may host additional submicroscopic CNVs which are not located at the breakpoints. Due to the high-resolution, high-throughput and high-accuracy, array-CGH is considered to be a powerful tool for submicroscopic CNVs detection.</p>

ASS1 mutation leading to citrullinemia I in a Chinese Han family / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate potential mutation of the ASS1 gene in a male infant with acute citrullinemia type I.</p><p><b>METHODS</b>Genomic DNA was prepared from peripheral blood samples of the family members. Mutation analysis of the 14 ASS1 exons was carried out by PCR and direct DNA sequencing.</p><p><b>RESULTS</b>A homozygous missense mutation of c.970G>A located in exon 13, which results in p.G324S, was identified in the child. Sequencing of the parents showed a heterozygous status for the same mutation.</p><p><b>CONCLUSION</b>A missense mutation of c.970G>A in the ASS1 gene is responsible for the pathogenesis of the disease in the infant.</p>

Results of second-trimester prenatal screening using two serum markers for Down's syndrome in 60 931 pregnant women / 中华围产医学杂志

Objective To approach the efficiency of second-trimester prenatal screening using two serum markers for Down's syndrome (DS).Methods Retrospective analysis was conducted on the results of prenatal screening using two serum markers,alpha fetoprotein (AFP) and free beta subunit of human chorionic gonadotropin(free-β-hCG),in 50 cases of DS pregnancy identified among 60 931 pregnant women received prenatal screening from November 1997 to April 2008 in Nanjing Maternal and Child Health Hospital.Results Among the 50 DS cases,the detection rate of DS was 50% (25/50) when taking free-β-hCG≥2.5 MoM as the cut-off,with the positive rate of screening was 6.6%.And the detection rate of DS would be 18.0%(9/25) when taking AFP≤0.5 MoM as the cut-off,with the positive rate of screening was 4.6%.When the risk cut-off value of DS was set at 1/270,the detection rate changed to 52.0%,and the positive rate of screening was 4.7%;and the two figures changed to 62.0% and 5.5%,respectively,when the risk cut-off was set to 1/300.Thirteen DS cases showed the risk value between 1/1000 and 1/300,among which two were monomarker abnormality.Thirteen (26.0%) of the 50 DS fetus were found to have one or two abnormality markers by ultrasound scan,among which one was DS low risk,and the other 12 were DS high risk in serum screening.Conclusions The second-trimester prenatal screening using AFP or free β-hCG for Down's syndrome is effective in identifying DS pregnancy with limited specificity and sensitivity.But the detection rate can be elevated by the combination of these two markers.The second trimester systemic ultrasound scan is not ideal for DS identification,but it can increase the specificity and sensitivity of serum prenatal screening.