Diagnosis and reproductive guidance for a couple carrying a novel c.1893C>T mutation of the TECTA gene / 中华医学遗传学杂志

OBJECTIVE@#To explore the molecular basis for an individual with postnatal deafness and provide genetic counseling for her family.@*METHODS@#Following extraction of genomic DNA from peripheral blood samples, 127 genes associated with deafness were subjected to targeted capturing and next generation sequencing. Suspected mutation was verified by Sanger sequencing.@*RESULTS@#The proband was found to carry a homozygous c.1893C>A mutation in the TECTA gene, which is located in the tectorial membrane of inner ear and may cause premature termination of translation of TECTA protein. In addition, two heterozygous mutations, c.13010C>T and c.12790G>A, were found in the USH2A gene. Whilst the former is likely to be pathogenic, the latter has unknown clinical significance. Further analysis suggested that all three mutations have derived from the parents of the proband.@*CONCLUSION@#The homozygous c.1893C>A mutation of the TECTA gene probably underlies the proband's hearing loss which conformed to an autosomal recessive inheritance.

Prenatal diagnosis of a tetrasomy 18p case using BACs-on-Beads technology and single nucleotide polymorphism array / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To determine the origin of a supernumerary small marker chromosome found in a fetus using prenatal BACs-on-Beads (BoBs) and single nucleotide polymorphism array (SNP-array) assays.</p><p><b>METHODS</b>The fetal sample was subjected to chromosomal karyotyping and BoBs analysis, and the results were validated with genome-wide scanning using a SNP microarray.</p><p><b>RESULTS</b>The fetus was found to have a 47,XX,+mar karyotype. BoBs analysis indicated that there was an amplification between 18p11.32 and 18p11.21, which was verified by the SNP-array assay as a 18.3 Mb duplication occurring at 18p11.32q11.1.</p><p><b>CONCLUSION</b>The karyotype of the fetus was determined as 47,XX,+der18(18p11.32?18q11.1::18q11.1?18p11.32). The duplication has involved important genes including SMCHD1, LPIN2 and TGIF1, which may result in severe malformations in the fetus.</p>

Detection of cell-free fetal DNA in maternal plasma for noninvasive prenatal screening of fetal chromosomal aneuploidies in women of advanced maternal age / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To evaluate the efficiency of cell-free fetal DNA detection as a non-invasive prenatal screening (NIPS) method for women of advanced maternal age.</p><p><b>METHODS</b>A total of 10 584 women of advanced maternal age who received NIPS were recruited from the Women's Hospital, Zhejiang University School of Medicine and Jiaxing Maternal and Child Health Hospital during February 2015 and September 2016. The pregnancy outcome was followed-up. The sensitivity, specificity, positive and negative predictive value of fetal chromosomal aneuploidy detected in NIPS were analyzed. And the relationship between maternal age and fetal common chromosomal aneuploidy was analyzed.</p><p><b>RESULTS</b>The sensitivity, specificity, positive and negative predictive value of NIPS were 100.00%, 99.96%, 91.67%, 100.00% for trisomy 21, 100.00%, 99.93%, 68.18%, 100.00% for trisomy 18, and 100.00%, 99.97%, 25.00%, 100.00% for trisomy 13. High-risk rate and true positive rate of trisomy 21 were positively correlated with the maternal age (all<0.01). There were significant differences in high-risk rate and true positive rate between 35-37 year old groups and 38-40 year old groups (all<0.05). Such difference was also found in high-risk rate between 38-40 year old group and ≥ 41 year old group (<0.05), but not in true positive rate between two groups (>0.05).</p><p><b>CONCLUSIONS</b>NIPS is effective for fetal chromosomal aneuploidy screening in women of advanced maternal age. For women under 38 years of age, NIPS is preferred; for women of 41 and above, invasive diagnostic methods are suggested; and for women between 38-41 years old, the option can be determined by themselves after risks and advantages were fully informed.</p>

A case of Wolf-Hirschhorn syndrome diagnosed by single nucleotide polymorphism array / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the genetic causes for a child with multiple congenital malformations and epilepsy through analysis of copy number variations, and to correlate the genotype with the phenotype.</p><p><b>METHODS</b>G-banding karyotyping was performed on the child and her parents. Single nucleotide polymorphisms array (SNP-array) was used to map the exact chromosomal breakpoints in the proband. The result was validated with fluorescence in situ hybridization (FISH).</p><p><b>RESULTS</b>G banding analysis suggested that the proband had a karyotype of 46,XX,del(4)(p15), while both of his parents had a normal karyotype. SNP-array has identified a hemizygous deletion of 13.3 Mb on chromosome 4p16.3p15.33, which has been implicated in Wolf-Hirschhorn syndrome. FISH assay has confirmed the de novo origin of the deletion, with the karyotype and clinical phenotype of both parents taken into consideration.</p><p><b>CONCLUSION</b>A case of Wolf-Hirschhorn syndrome has been diagnosed by clinical manifestation and karyotyping analysis. Compared with conventional karyotyping analysis, SNP-array has greater resolution and accuracy, and can provide useful information for genetic counseling.</p>

Prenatal diagnosis of a Pallister-Killian syndrome case through analysis of a supernumerary chromosome using single nucleotide polymorphism array / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the origin of a supernumerary small marker chromosome (sSMC) in a fetus, and to assess the feasibility of single nucleotide polymorphism array (SNP-array) for prenatal diagnosis.</p><p><b>METHODS</b>The fetal sample was subjected to karyotyping analysis. The identified sSMC was subjected to genome-wide scan using a SNP microarray chip. The results were validated with fluorescence in situ hybridization (FISH).</p><p><b>RESULTS</b>The karyotype of the fetus was determined as 47,XX,+mar, which was verified by SNP microarray chip analysis as a 34.6 Mb duplication in 12p13.33p11.1. FISH analysis confirmed that the sSMC has originated from chromosome 12p.</p><p><b>CONCLUSION</b>The karyotype of the fetus was determined as 47,XX,+i(12)(p10). Tetrasomy 12p is reported to be a marker for Pallister-Killian syndrome, which may result in multi-system anomalies. SNP-array analysis can simultaneously detect microdeletions and microduplications, which may be used for prenatal diagnosis of suspected cases.</p>

Diagnosis of a case with Williams-Beuren syndrome by single nucleotide polymorphism array / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the genetic cause for a child with mental retardation, developmental delay and multi-systemic developmental disorders by analyzing the copy number variations (CNVs) and correlating the genotype with the phenotype.</p><p><b>METHODS</b>Routine G-banding was performed to analyze the karyotype of the patient and her parents. In addition, single nucleotide polymorphisms array (SNP-array) was used to determine the CNVs, which was confirmed by fluorescence in situ hybridization (FISH).</p><p><b>RESULTS</b>No karyotypic abnormality was detected upon chromosome analysis. However, SNP-array has identified a de novo hemizygous deletion of 1673 kb on chromosome region 7q11.23, which has been associated with Williams-Beuren syndrome. The microdeletion was confirmed by FISH testing.</p><p><b>CONCLUSION</b>A child with Williams-Beuren syndrome has been diagnosed by SNP-array and FISH. The de novo 7q11.23 microdeletion probably underlies the clinical manifestation of the patient. Compared with routine karyotype analysis, SNP-array is more useful for diagnosing children with multiple congenital anomalies with unclear etiology.</p>

Multiple of the median correction of Down's syndrome serum markers with pregnant body weight / 中华检验医学杂志

Objective With Pregnant women weight correction for serum marker Multiple of Median (MoM) of First trimester and second-trimester,integrated screen-ing for Down's syndrome (DS),can reduce the false positive rate.Methods The same pregnant woman were taken venous blood vessels with sterile vacuum during the first trimester (11-13 W(+ 6) d) and the second trimester (15-20 W(+ 6) d),Alpha-fetoprotein (AFP),serum free beta-human chorionic gonadotrophin (Free beta hCG) and pregnancyassociated protein-A (PAPP-A) of three kinds of serum marker screening indicators were assayed by Using Time-resolved fluoroimmunoassay (TRFIA).Screening for risk assessment software was used to calculate serum marker Multiple of Median,To assess the risks of 7 997 cases of local pregnant women DS,To construct the weight equation of local population using nonlinear weighted regression method,With maternal weight correction for serum marker Multiple of Median (MoM) of local pregnant women,Comparing the changes of screening index MoM before and after correction,chi square test to compare the detection rate and false positive rate.Results MoM values of three kinds of serum markers (al-pha-fetoprotein,free beta subunit of human chorionic gonadotropin,pregnan-cy-associated plasma protein A) decreased with the weight increasing,Screening index MoM after correction weight equation,the screening of false positives for crowd from 4.12％ down to 3.86％ (x2 =0.021,P ＞ 0.05).Setting threshold (cut-off) at 1/270,and no change detection rates were 71.4％ the local population before and after correction weight equation.Conclusion Maternal weight may affect the results of Down's syn-drome sereening.When screening proposal to set up,it is worth making weight cor-rections for serum maker multiple of median in order to get accurate risk calculation results.

First trimester combined screening for Down's Syndrome with NT, Free-βhCG and PAPP-A / 中华检验医学杂志

Objective To explore the sensitivity of using NT,combined with serum biochemical markers (Free-βhCG,PAPP-A) for Down's Syndrome screening in early stage of pregnancy.Methods Collect pregnant women aged 17-45 years old voluntary antenatal screening in our hospital from March 2009to October 2010,a total of 11882 cases.Serum Free-βhCG and PAPP-A were measured NT value was determined by ultrasound at 11-13w+64 of gestation.Calculating combined screening (NT,Free-βhCG,PAPP-A),and serum integrated screening (Free-beta hCG,PAPP-A) risk,respectively,using the risk calculation software for the same person.Results Early pregnancy screening was performed in 11 882patients,18 had a fetus with Down's syndrome,a rate of 0.15％.The detection rates of Down's syndrome in combined screening and serum integrated screening were 83.3％ and 72.2％ respectively.The specificities were 98.4％ and 97.3％ and detection efficiency were 7.18％,3.90％ respectively.Areas under the curve (AUCs) of fhst-trimester combined screening and serum integrated screening were 0.975 (95％ CI:0.943,1.007),0.901 (95％ CI:0.789,1.013) respectively.Conclusion In early stage of pregnancy,combined screening for Down's syndrome has higher sensitivity and specificity than serological screening,has higher detection rate in the same false-positive rate case,which can effectively reduce the pregnant women to receive invasive puncture.

A comparison between real-time quantitative fluorescence polymerase chain reaction assay and direct immunofluorescence assay for diagnosis of human metapneumovirus / 中华检验医学杂志

Objectives To evaluate the diagnostic value of real-time quantitative fluorescence polymerase chain reaction( Q-RT-PCR ) assay and immunofluorescence assay for diagnosis of hMPV. Methods Totally 1 283 children with acute respiratory infection admitted in Jiaxing Maternity and Child Health Care Hospital for treatment from November 2008 to May 2009 were recruited in this study. The hMPV positive stains were separated and sequenced in this area. The sequences between the local hMPV stains and Holland stains NLD00-1 were compared. The specific primers and fluorescent probe were designed according to the sequence of epidemic hMPV strain. The Taqman methodology was applied in Q-RT-PCR. Negative pressure suction was used to acquire nasopharyngeal secretions specimens. Both Q-RT-PCR and immunofluorescence with FITC labeled monoclonal antibody were used to analyze them, respectively. The McNemar, test was applied to analyze the correlation between the two methods. Results Totally 1 283 specimens were analyzed with Q-RT-PCR and immunofiuorescence simultaneously. Q-RT-PCR analysis showed there were 59 cases positive. Immunofluorescence analysis showed there were 55 cases positive. Fifty-two cases were positive in both assays. There were 7 cases positive in Q-RT-PCR assay but negative in immunofluorescence assay and 3 cases negative in Q-RT-PCR assay but positive in immunofluorescence assay. If Q-RT-PCR method was set as the golden standard, the sensitivity and specificity for immunofluorescence detection method were 88. 1%and 99. 8%, respectively. Positive predictive value and negative predictive value were 94. 5% and 99. 4%,respectively. There was no significant difference ( χ2= 0. 9, P ＞ 0. 05 ) by McNemar' test between the two methods. Conclusion The diagnostic value of immunofluorescence assay is close to Q-RT-PCR assay.