Prenatal diagnosis and pregnancy outcome of fetuses with rare autosomal trisomies indicated by non-invasive prenatal testing / 中华医学遗传学杂志

OBJECTIVE@#To analyze the result of prenatal diagnosis and outcome of pregnancy for fetuses with rare autosomal trisomies (RATs) suggested by non-invasive prenatal testing (NIPT).@*METHODS@#A total of 69 608 pregnant women who underwent NIPT at Genetics and Prenatal Diagnosis Center of the First Affiliated Hospital of Zhengzhou University from January 2016 to December 2020 were selected as study subjects. The result of prenatal diagnosis and outcome of pregnancy for those with a high risk for RATs were retrospectively analyzed.@*RESULTS@#Among the 69 608 pregnant women, the positive rate of NIPT for high-risk RATs was 0.23% (161/69 608), with trisomy 7 (17.4%, 28/161) and trisomy 8 (12.4%, 20/161) being the most common, and trisomy 17 (0.6%, 1/161) being the rarest. For 98 women who had accepted invasive prenatal diagnosis, 12 fetal chromosomal abnormalities were confirmed, and in 5 cases the results were consistent with those of NIPT, which yielded a positive predictive value of 5.26%. Among the 161 women with a high risk for RATs, 153 (95%) were successfully followed up. 139 fetuses were ultimately born, with only one being clinically abnormal.@*CONCLUSION@#Most women with a high risk for RATs by NIPT have good pregnancy outcomes. Invasive prenatal diagnosis or serial ultrasonography to monitor fetal growth, instead of direct termination of pregnancy, is recommended.

The value of re-sampling for patients who had failed non-invasive prenatal testing due to low cell-free fetal DNA fraction / 中华医学遗传学杂志

OBJECTIVE@#To assess the value of re-sampling for patients who had failed non-invasive prenatal testing (NIPT) due to low cell-free fetal DNA (cffDNA) fraction.@*METHODS@#Clinical data of 20 387 patients undergoing NIPT test was reviewed. The patients were re-sampled when initial blood test did not yield a result due to cffDNA fraction. The results were analyzed, and the outcome of pregnancy was followed up.@*RESULTS@#Among all samples, 17 (0.08%) had failed to yield a result due to low cffDNA fraction, all of which accepted re-sampling. A result was attained in 16 cases, with a success rate of 94.12%. Only one sample had failed the re-test.@*CONCLUSION@#For patients who had failed the initial NIPT due to low cffDNA fraction, re-sampling should be considered with gestational week and ultrasound results taken into consideration.

Analysis of a case with heterozygous 14q12 deletion and FOXG1 gene-related disease / 中华医学遗传学杂志

OBJECTIVE@#To describe the clinical and genetic characteristics of a child with 14q12q13.1 deletion involving the FOXG1 gene.@*METHODS@#Clinical manifestation of the child was analyzed. Peripheral blood sample of the patient was subjected to chromosomal karyotyping and single nucleotide polymorphism array (SNP-array) analysis.@*RESULTS@#The male infant has developed feeding difficulty, poor sucking, lower limb tremor, and frontal bruising 8 days after birth. Magnetic resonance imaging revealed significant enlargement of bilateral ventricles and corpus callosum dysplasia. Chromosomal analysis revealed a karyotype of 46,XY,del(14)(q12q13.1), and SNP-array confirmed that there was a 9.6 Mb deletion in 14q11.2q13.1, which encompassed the FOXG1 gene.@*CONCLUSION@#For patients with brain development abnormalities, dyskinesia, cognitive impairment, speech disorder and other manifestations, copy number variation of the FOXG1 gene should be excluded. SNP-array should be carried out as early as possible to attain the diagnosis.

Non-invasive prenatal detection of ocutaneous albinism type I based on cfDNA barcode-enabled single-molecule test / 中华医学遗传学杂志

OBJECTIVE@#To assess the value of non-invasive prenatal testing based on cfDNA barcode-enabled single-molecule test (cfBEST) for the prenatal diagnosis of oculocutaneous albinism type I in a family.@*METHODS@#Prenatal genetic diagnosis was carried out by using the cfBEST-based method as well as invasive prenatal diagnosis through amniocentesis. The outcome of the pregnancy was followed up.@*RESULTS@#Non-invasive prenatal testing based on cfBEST showed a fetal DNA concentration of 6.6%, with the proportion of c.929_930insC (p.Arg311Lysfs*7) and c.1037-7T>A mutations being 45.7% and 0%, respectively. The posterior frequency of the negative results was 1, suggesting that the fetus carried neither of the two mutations. The result was consistent with that of invasive prenatal diagnosis, and the follow-up found that the fetus was normal.@*CONCLUSION@#Non-invasive prenatal testing based on cfBEST can be used to detect maternal and fetal genotypes in maternal cell-free DNA, which is clinically feasible.

Results of non-invasive prenatal testing for 2473 women with twin pregnancy / 中华医学遗传学杂志

OBJECTIVE@#To assess the value of non-invasive prenatal testing (NIPT) for the detection of fetal chromosomal aneuploidies in women with twin pregnancy.@*METHODS@#A total of 2473 women with twin pregnancy underwent the NIPT test to assess the risk for fetal chromosomal aneuploidies from January 2016 to September 2019. Those with a high risk by NIPT were confirmed by amniocentesis or chorionic villus sampling. All cases were followed up to evaluate the positive prediction value of NIPT for twin pregnancies.@*RESULTS@#Among the 2473 women, the NIPT test has identified 31 cases (1.25%) with a high risk for fetal chromosomal aneuploidies, which included 5 cases of trisomy 21, 1 case of chromosome 21 deletion, 4 cases of trisomy 18, 7 cases of sex chromosome abnormality and 14 cases of microdeletion and microduplication. By invasive prenatal diagnosis or chromosomal karyotyping analysis of neonates, 5 cases of trisomy 21, 3 cases of trisomy 18, 1 case of sex chromosome abnormality, and 2 cases of microdeletion and microduplication were confirmed, which yielded a positive predictive value of 100%, 75%, 25% and 25%, respectively.@*CONCLUSION@#NIPT can be used for the screening of fetal chromosomal aneuploidies in women with twin pregnancy with high accuracy. The method is non-invasive, safe and effective for the screening of fetal chromosomal aneuploidies, in particular trisomy 21.

Non-invasive prenatal test for autosomal dominant Charcot-Marie-Tooth disease in a fetus using droplet digital polymerase chain reaction / 中华围产医学杂志

We report the use of droplet digital polymerase chain reaction (ddPCR) in non-invasive prenatal test fetal Charcot-Marie-Tooth disease (CMT) caused by MFN2 gene mutation. The proband, namely the husband, was found with heterozygous mutation of c.919A>G(p.K307E) in the MFN2 gene, which was diagnosed as CMT type 2A2A at a local hospital. The proband's wife underwent genetic counseling after conception at the First Affiliated Hospital of Zhengzhou University. Peripheral blood obtained from the pregnant woman was analyzed by ddPCR at eight gestational weeks, which found the fetus to carry a paternal pathogenic gene mutation. Sanger sequencing for the chorionic sample at 11 gestational weeks further verified that the fetus was a c.919G>A(p.K307E) heterozygous mutation carrier, the same as the proband. ddPCR could be applied to cell-free fetal DNA to detect the paternal pathogenic gene mutation in the non-invasive prenatal test.

Cell-free DNA barcode-enabled single-molecule test for non-invasive prenatal diagnosis of phenylketonuria: an analysis of four cases / 中华围产医学杂志

Objective:To analyze the applicability and feasibility of a cell-free DNA barcode-enabled single-molecule test (cfBEST) in non-invasive prenatal diagnosis of phenylketonuria.Methods:This study recruited four pregnant women who were prenatally diagnosed as heterozygous carriers of hot spot mutations in the PAH gene from pedigrees with phenylketonuria at the First Affiliated Hospital of Zhengzhou University from July to September 2019. The frequency of mutations in maternal plasma cell-free DNA and the fetuses' genotypes were analyzed by cfBEST. Nested polymerase chain reaction primers were designed to amplify the mutation sites in each pedigree. The results of cfBEST were compared with those of invasive prenatal diagnosis. Descriptive analysis was used for data analysis. Results:In pedigree 1, the frequency of c.603T>G and c.842+2T>A mutations in maternal plasma cell-free DNA were 48.40% (291/601) and 9.70% (61/628), which was detected by cfBEST. The fetus was diagnosed with phenylketonuria with two heterozygous mutations. In pedigree 2, the frequency of c.1238G>C and c.842+2T>A mutations in maternal plasma cell-free DNA was 43.70% (786/1 798) and 0% (0/1 550), respectively. Both mutations were wild-type, and the fetus was neither phenylketonuria nor a carrier. In pedigree 3, the frequency of c.1045T>G and c.728G>A mutations in maternal plasma cell-free DNA was 44.00% (930/2 112) and 0% (0/705), respectively, suggesting that both mutations in the fetus were wild-type, and the fetus was neither phenylketonuria nor a carrier. In pedigree 4, the frequency of c.755G>A and c.728G>A mutations were 45.40% (743/1 637) and 4.50% (28/849), respectively, which indicated that the former was wild-type, and the latter was heterozygous; namely the fetus was a carrier of phenylketonuria. The results of cfBEST were consistent with those of invasive prenatal diagnosis. Three pedigrees (Pedigree 2, 3 and 4) continued the pregnancy to full-term, and the phenylalanine levels in the neonates were all below 120 μmol/L. No abnormalities were reported in those three infants during follow-ups at one, three, and six months after birth.Conclusions:The cfBEST could be used for non-invasive prenatal diagnosis of phenylketonuria caused by PAH gene mutation, but further studies with a larger sample size are needed.

Genetic testing and prenatal diagnosis for a Chinese pedigree affected with Meckel-Gruber syndrome / 中华医学遗传学杂志

OBJECTIVE@#To carry out genetic testing and prenatal diagnosis for a Chinese couple whom had conceived two fetuses featuring multiple malformations including polycystic kidney, polydactyly and encephalocele.@*METHODS@#Following elective abortion, the fetus from the second pregnancy was subjected to whole exome sequencing. Suspected pathogenic variants were verified by Sanger sequencing of the fetus and its parents.@*RESULTS@#The fetus was found to harbor compound heterozygous variants of the CEP290 gene, namely c.2743G>T (p.E915X) and c.2587-2A>T, which were respectively inherited from its father and mother. The same variants were not detected among 100 healthy controls nor reported previously. Bioinformatic analysis suggested both variants to be deleterious. The fetus was diagnosed with Meckel-Gruber syndrome. Prenatal diagnosis for the couple during their next pregnancy suggested that the fetus did not carry the above pathogenic variants.@*CONCLUSION@#The compound heterozygous variants of the CEP290 gene probably underlay the pathogenesis of Meckel-Gruber syndrome in the second fetus. Above finding has provided a basis for genetic counseling and prenatal diagnosis for the couple, and also enriched the mutational spectrum of the CEP290 gene.

Analysis of the effect of expanded non-invasive prenatal testing in prenatal screening population during pregnancy / 中华医学遗传学杂志

OBJECTIVE@#To explore the clinical effect of expanded non-invasive prenatal testing (NIPT-plus) for prenatal screening.@*METHODS@#The screening result, prenatal diagnosis and pregnancy outcome of 3700 pregnant women who volunteered NIPT-plus screening at our center from September 2018 to December 2019 were reviewed.@*RESULTS@#Among the 3700 pregnant women, 74(2.0%) were scored positive for clinically significant fetal chromosomal abnormalities and underwent NIPT-plus screening. Sixty three women with a high risk underwent invasive prenatal diagnosis, among whom 19 were diagnosed, which yielded a positive predictive value (PPVs) of 30.2% (19/63). Statistical analysis showed that NIPT-plus has higher PPVs for common aneuploidies and low-to-medium PPVs for sex chromosome aneuploidies and microdeletion/microduplication syndromes.@*CONCLUSION@#As a screening technique, NIPT-plus has broader applications compared with conventional techniques, and has reference value for clinicians and pregnant women during pregnancy.

Is it necessary to choose NIPT-plus for pregnant women who opt for non-invasive prenatal testing? A study of 50 cases / 中华医学遗传学杂志

OBJECTIVE@#To explore whether it is necessary to choose NIPT-plus for the prenatal screening of pregnant women.@*METHODS@#The results of NIPT and NIPT-plus sequencing data, fetal DNA concentration, prenatal diagnosis and pregnancy outcome of 50 pregnant women were compared.@*RESULTS@#Compared with NIPT, NIPT-plus attained similar fetal DNA concentration and a 4.4-fold increase in sequencing data. NIPT was able to detect 4 cases of 21-trisomy, 2 cases of 18-trisomy, and 9 cases of sex chromosome aneuploidies (SCAs) signaled by NIPT-plus, but missed one 18-trisomy, and failed to detect rare chromosome aneuploidies (RCAs) and microdeletion/microduplication syndromes (MMS). The PPVs of NIPT-plus for 21-trisomy, 18-trisomy, SCAs, MMS and RCAs were 100%, 100%, 44.4%, 30.4% and 0%, respectively. And those of NIPT for 21-trisomy, 18-trisomy, and SCAs were 100%, 100%, and 44.4%, respectively.@*CONCLUSION@#It is necessary for pregnant women to select NIPT-plus to improve the detection rate of common trisomies, SCAs and disease-specific MMS, therefore reduce the occurrene of birth defect.

Application of bionano optical mapping for the diagnosis of a 16p11.2-p12.2 microdeletion / 中华医学遗传学杂志

OBJECTIVE@#To delineate chromosomal aberration caused by structural chromosomal abnormalities with bionano optical mapping.@*METHODS@#Chromosomal karyotyping, bionano optical mapping and copy number variation sequencing (CNV-seq) were used to delineate the chromosomal aberration carried by a patient.@*RESULTS@#The patient was found to have an anomalous chromosome 16 by karyotyping analysis, which was verified by bionano optical mapping and CNV-seq as loss of heterozygosity at 16p11.2-p12.2.@*CONCLUSION@#Bionano optical mapping has provided a novel tool for the detection and diagnosis of structural chromosomal aberrations.

Non-invasive prenatal diagnosis of ectodermal dysplasia caused by EDA gene mutation: a case report / 中华围产医学杂志

We report a case of non-invasive prenatal diagnosis of fetal ectodermal dysplasia caused by EDA gene mutations. The pregnant woman underwent prenatal diagnosis at 11 gestational weeks because of a childbearing history of ectodermal dysplasia. Cell-free DNA barcode-enabled single-molecule test (cfBEST) was used to detect the ectodermal dysplasia gene mutation, and chorionic villus sampling was also performed. The cfBEST results showed that the genotype of maternal EDA gene c.340C> T(p.Gln114*) was heterozygous, while the genotype of fetal EDA was normal wild-type (C/C), which were consistent with the results of villus sampling, suggesting that cfBEST can be used for non-invasive prenatal diagnosis of ectodermal dysplasia caused by EDA gene mutation.

Spectrum of pathological genetic variants among 405 Chinese pedigrees affected with oculocutaneous albinism / 中华医学遗传学杂志

OBJECTIVE@#To determine the spectrum of pathological genetic variants among 405 Chinese pedigrees affected with oculocutaneous albinism (OCA).@*METHODS@#A total of 405 OCA patients were collected. High-throughput sequencing (The panel included TYR, OCA2, TYRP1 and SLC45A2 genes), Sanger sequencing and multiplex ligation-dependent probe amplification (MLPA) were used to analyze the genetic variants and patterns of each subtype.@*RESULTS@#The overall detection rate of genetic variants was 79.9% (647/810), and the variants included missense variants (57.3%, 371/647), frameshift variants (22.9%, 148/647), nonsense variants (13.9%, 90/647), splicing variants (5.6%, 36/647), and microdeletions (0.3%, 2/647). Thirty-six novel variants were detected. Of the 405 patients, 306 have carried 2 variant alleles (75.6%, 306/405), 35 carried 1 variant alleles (8.6%, 35/405), while no variant was detected in 64 patients. Among the 306 genetically diagnosed OCA patients, OCA1 was the most common form (74.5%, 228/306), compared with OCA2 (15.0%, 46/306), OCA3 (0.7%, 2/306) and OCA4 (9.8%, 30/306), respectively. One patient was found to harbor homozygous c.1262-4_c.1262-3insTAGA variant of the TYRP1 gene. Another patient was found to carry compound heterozygous variants of c.1214C>A (p.T405N) and c.1338delinsCG(p.V447Gfs*19) of the TYRP1 gene.@*CONCLUSION@#High-throughput sequencing in combination with Sanger sequencing and MLPA can effectively detect genetic variants associated with OCA. Above finding has expanded variant spectrum of OCA, which can facilitate genetic and prenatal diagnosis of this disease in China.

Upregulation of SIRT1 by 17β-estradiol depends on ubiquitin-proteasome degradation of PPAR-γ mediated by NEDD4-1

17β-estradiol (E2) treatment of cells results in an upregulation of SIRT1 and a down-regulation of PPARγ. The decrease in PPARγ expression is mediated by increased degradation of PPARγ. Here we report that PPARγ is ubiquitinated by HECT E3 ubiquitin ligase NEDD4-1 and degraded, along with PPARγ, in response to E2 stimulation. The PPARγ interacts with ubiquitin ligase NEDD4-1 through a conserved PPXY-WW binding motif. The WW3 domain in NEDD4-1 is critical for binding to PPARΓ. NEDD4-1 overexpression leads to PPARγ ubiquitination and reduced expression of PPARγ. Conversely, knockdown of NEDD4-1 by specific siRNAs abolishes PPARΓ ubiquitination. These data indicate that NEDD4-1 is the E3 ubiquitin ligase responsible for PPARγ ubiquitination. Here, we show that NEDD4-1 delays cellular senescence by degrading PPARΓ expression. Taken together, our data show that E2 could upregulate SIRT1 expression via promoting the PPARΓ ubiquitination-proteasome degradation pathway to delay the process of cell senescence.