Amniotic Fluid Karyotype Research Articles

Correlation between maternal serum biomarkers and the risk of fetal chromosome copy number variants: a single-center retrospective study.

To explore the association between the concentration of maternal serum biomarkers and the risk of fetal carrying chromosome copy number variants (CNVs). Pregnant women identified as high risk in the second-trimester serological triple screening and underwent traditional amniotic fluid karyotype analysis, along with comparative genomic hybridization array (aCGH)/copy number variation sequencing (CNV-seq), were included in the study. We divided the concentration of serum biomarkers, free beta-human chorionic gonadotropin (fβ-hCG), alpha fetoprotein (AFP) and unconjugated estriol (uE3), into three levels: abnormally low, normal and abnormally high. The prevalence of abnormally low, normal and abnormally high serum fβ-hCG, AFP and uE3 levels in pregnant women with aberrant aCGH/CNV-seq results and normal controls was calculated. Among the 2877 cases with high risk in the second-trimester serological triple screening, there were 98 chromosome abnormalities revealed by karyotype analysis, while 209 abnormalities were detected by aCGH/CNVseq (P＜0.001) . The carrying rate of aberrant CNVs increased significantly when the maternal serum uE3 level was less than 0.4 multiple of median (MoM) of corresponding gestational weeks compared to normal controls, while the carrying rate of aberrant CNVs decreased significantly when the maternal serum fβ-hCG level was greater than 2.5 MoM compared to normal controls. No significant difference was found in the AFP group. Low serum uE3 level (<0.4 MoM) was associated with an increased risk of aberrant CNVs.

Amniotic fluid karyotype analysis and prenatal diagnosis strategy of 3117 pregnant women with amniocentesis indication.

Aim: To examine prenatal diagnosis strategies through fetal karyotype analysis for 3117 pregnant women with genetic amniocentesis indications. Materials & methods: According to the different indications for amniocentesis, the study was divided into 8 groups. The number of amniocentesis specimens, the number of abnormal karyotypes and the positive rate of each group were analyzed. Results: Compared with prenatal serum screening, noninvasive prenatal DNAtesting is more accurate and can effectively improve screening efficiency. Multiple prenatal diagnosis indicators (37.349%) were more likely to be detected than single prenatal diagnosis indicators (11.091%). Conclusion: None of the screening methods can completely replace amniocentesis, and for pregnant women with genetic indications for amniocentesis, amniocentesis is strongly recommended.

Value of noninvasive prenatal testing in the detection of rare fetal autosomal abnormalities

ObjectivesTo evaluate the value of noninvasive prenatal testing (NIPT) in the screening of rare autosomal abnormalities and provide further support for the clinical application of NIPT. Study designA total of 81,518 pregnant women who underwent NIPT at the Anhui Maternal and Child Health Hospital between May 2018 and March 2022 were selected. The high-risk samples were analyzed using amniotic fluid karyotype and chromosome microarray analysis (CMA), and the pregnancy outcomes were followed up. ResultsNIPT detected 292 cases (0.36%) with rare autosomal abnormalities among the 81,518 cases sampled. Of these, 140 (0.17%) showed rare autosomal trisomies (RATs), and 102 of these patients agreed to undergo invasive testing. Five cases were true positives, with a positive predictive value (PPV) of 4.90%. Copy number variants (CNV) were detected in 152 samples of the total cases (0.19%), and 95 of the patients involved agreed to the use of CMA. Twenty-nine of these cases were confirmed to be true positive, with a PPV of 30.53%. Detailed follow-up information was obtained in 81 cases from 97 patients with false-positive results for RATs. Thirty-seven of these cases (45.68%) had adverse perinatal outcomes, with a higher incidence of small for gestational age (SGA), intrauterine growth retardation (IUGR), and preterm birth (PTB). ConclusionsNIPT is not recommended for screening for RATs. However, considering that positive results are associated with an increased risk of IUGR and PTB, additional fetal ultrasound examination should be performed to monitor fetal growth. In addition, NIPT has a reference value in screening for CNVs, especially pathogenic CNVs, but a comprehensive analysis of prenatal diagnosis combined with ultrasound and family history is still needed.

Early warning of low maternal unconjugated estriol level by prenatal screening for fetus with X-linked ichthyosis

Objective: To analyze the characteristic of prenatal serological screening in fetus with X-linked ichthyosis (XLI), and to explore the relationship between unconjugated estriol (uE3) levels and XLI. Methods: A total of 56 fetuses with Xp22.31 microdeletion indicated by prenatal diagnosis and 70 fetuses diagnosed with trisomy 21 and 26 fetuses with trisomy 18 in Henan Provincial People's Hospital and Affiliated Hospital of Weifang Medical College from September 2016 to June 2021 were collected. The multiples of median (MoM) values of uE3, alpha-fetoprotein (AFP), and human chorionic gonadotropin (hCG) during the second trimester of pregnancy were retrospectively analyzed. Prenatal diagnosis was made by amniotic fluid karyotype analysis and genome copy number variant analysis, parent genetic verification and pathogenicity analysis were performed, and maternal and infant outcomes were followed up. Results: Of 56 pregnant women with fetal Xp22.31 microdeletion, 43 underwent serological screening during the second trimester of pregnancy, of which 42 were abnormal (39 male fetuses and 3 female fetuses). The median uE3 MoM value of 39 male fetuses [0.06 (0.00-0.21)] was lower than the normal value and significantly lower than that of fetuses with trisomy 21 [0.71 (0.26-1.27)] and fetuses with trisomy 18 [0.36 (0.15-0.84)], the difference was statistically significant (Z=99.96, P<0.001). While the MoM values of AFP and hCG were all within the normal range. Among the 56 fetuses carrying Xp22.31 microdeletion, 45 were male fetuses and 11 were female fetuses, and the deletion fragments all involved STS gene. Eighty-nine percent (50/56) were inherited from mother (49 cases) or father (1 case), and 11% (6/56) were de novo mutations. Follow-up showed 48 live births (38 males and 10 females) and 8 chose to terminate pregnancy (7 males and 1 female). Among the 38 male newborns, 37 presented with scaly skin changes from 1 to 3 months of age, and one had no clinical manifestations until 4 months after birth. Ten female newborns had no obvious clinical manifestations. Conclusions: The decrease levels of uE3 MoM on maternal serological screening is closely related to the higher risk of XLI in male fetuses. For pregnant women with low uE3 in serological screening or with family history of ichthyosis, in addition to chromosomal karyotype analysis, joint detection of genomic copy number variant analysis should be recommended.

Clinical outcomes of 77 TESE treatment cycles in non-mosaic Klinefelter syndrome patients.

ObjectiveThe current study aimed to present the clinical outcomes of 76 azoospermic patients with non-mosaic Klinefelter syndrome (KS), treated with testicular spermatozoa extraction (TESE) followed by intracytoplasmic sperm injection (ICSI) using either fresh or cryopreserved testicular spermatozoa.MethodsWe retrospectively evaluated 76 patients with non-mosaic KS belonging to a special group of cases that besides infertility did not present the classical signs and symptoms of testosterone deficiency. One of the patients repeated the TESE procedure (76 patients, 77 TESE cycles). Sixty of these 76 patients accepted to undergo TESE associated with ovarian stimulation, while 16 patients underwent TESE followed by testicular spermatozoa cryopreservation. Aneuploidy screening of the offspring was performed by Multiplex ligation-dependent probe amplification and by amniotic fluid karyotyping. Statistical analysis used the Chi-Squared Test, Fisher's Exact Test, 2-sided, for rates, and the Independent Samples T-test for equality of means, 2-sided.ResultsTesticular spermatozoa were recovered in 31 (40.3%) of the attempts. The patients underwent 47 ICSI cycles, 25 with fresh testicular spermatozoa and 22 with cryopreserved testicular spermatozoa. Fertilization (63.5% vs. 41.6%, p=0.000), implantation (37% vs. 13.2%, p=0.014), clinical pregnancy (60.9% vs. 19%, p=0.005) and live birth (65.2% vs. 23.8%, p=0.006) rates were higher with fresh testicular spermatozoa. Chromosome analysis of the 21 newborns was normal.ConclusionsThe present data adds further information regarding the recovery rate of spermatozoa after TESE and the embryological and clinical outcomes with fresh and cryopreserved testicular spermatozoa, besides reassuring the safety concerning chromosomal transmission of KS from parents to their offspring.

Clinico- Radiologic and Genetic Study of Fraser Syndrome: A Case Report

Cryptophthalmos syndrome or Fraser syndrome is a rare autosomal recessive disorder, characterized by major features such as cryptophthalmos, cutaneous syndactyly, malformation of the larynx, abnormal genitalia, craniofacial dysmorphism, orofacial clefting, mental retardation and musculoskeletal anomalies. It is inherited in an autosomal recessive pattern where both the parents must be possessing one defective allele for Fraser syndrome. Since both the parents are carriers for the Fraser syndrome, there is a chance for 25% of their children being affected, 50% of their children to be carriers and 25% of their children to be normal. A 22 year old pregnant woman with a family history of third degree consanguineous marriage was diagnosed to have a fetus with many of the above findings in her anomaly scan which was done to manage child birth and as it is crucial to get prenatal diagnosis early in the pregnancy. Parents decided to terminate the pregnancy. Soon after the abortus was expelled, cord blood was collected and subjected to Karyotype test. Karyotype analysis revealed the absence of a short sequence on chromosome number 4 in q arm at 4q21 region, which may be responsible for the above mentioned deformities. Due to the high morbidity and mortality associated with Fraser syndrome, early detection by amniotic fluid karyotyping may be helpful in early intervention.

Application of Non-Invasive Prenatal Tests in Serological Preclinical Screening for Women with Critical-Risk and Low-Risk Pregnancies but Abnormal Multiple of the Median Values.

To explore the clinical value of secondary screening using noninvasive prenatal testing (NIPT) for women with critical-risk and low-risk pregnancies who had multiple of the median (MoM) abnormalities in serological screening. NIPT was used to analyze fetal free DNA in the peripheral blood of 2,325 women with critical-risk pregnancies and 239 women with low-risk pregnancies with MoM abnormalities in serological screening. Based on NIPT results, women with high-risk pregnancies were recommended for amniocentesis for fetal karyotype analysis. Among 2,325 women with critical-risk pregnancies as determined by serological screening, NIPT indicated 15 high-risk pregnancies (11 cases of trisomy 21 and 4 cases of trisomy 18). Of the 15 patients, 1 case refused prenatal diagnosis. The other 14 cases underwent invasive amniocentesis for fetal karyotype analysis, and 13 cases of fetal chromosomal abnormalities were diagnosed, including ten cases of trisomy 21 and three cases of trisomy 18. NIPT of 239 patients with low-risk pregnancies but abnormal MoM showed one case with a high risk of trisomy 21, which was diagnosed as a false positive by amniotic fluid karyotype analysis, and one case with a high risk of trisomy 13 (stillbirth) that was diagnosed by karyotype analysis. A case of gender chromosome abnormality was diagnosed as aneuploidy by karyotype analysis. The application of NIPT as a secondary screening for women with low- and critical-risk pregnancies as determined by serological screening but with MoM abnormalities will greatly reduce the number of invasive prenatal diagnosis procedures, significantly improve the rate and accuracy of fetal chromosomal abnormality detection.

A case of prenatal diagnosis of 18p deletion syndrome following noninvasive prenatal testing

BackgroundChromosome 18p deletion syndrome is a disease caused by the complete or partial deletion of the short arm of chromosome 18, there were few cases reported about the prenatal diagnosis of 18p deletion syndrome. Noninvasive prenatal testing (NIPT) is widely used in the screening of common fetal chromosome aneuploidy. However, the segmental deletions and duplications should also be concerned. Except that some cases had increased nuchal translucency or holoprosencephaly, most of the fetal phenotype of 18p deletion syndrome may not be evident during the pregnancy, 18p deletion syndrome was always accidentally discovered during the prenatal examination.Case presentationsIn our case, we found a pure partial monosomy 18p deletion during the confirmation of the result of NIPT by copy number variation sequencing (CNV-Seq). The result of NIPT suggested that there was a partial or complete deletion of X chromosome. The amniotic fluid karyotype was normal, but result of CNV-Seq indicated a 7.56 Mb deletion on the short arm of chromosome 18 but not in the couple, which means the deletion was de novo deletion. Finally, the parents chose to terminate the pregnancy.ConclusionsTo our knowledge, this is the first case of prenatal diagnosis of 18p deletion syndrome following NIPT.NIPT combined with ultrasound may be a relatively efficient method to screen chromosome microdeletions especially for the 18p deletion syndrome.

A prenatal diagnosis and genetics study of five pedigrees in the Chinese population with Xp22.31 microduplication

BackgroundCopy number variations (CNVs) can contribute to human phenotype, phenotypic diversity and disease susceptibility, while others may benign. In the current study, an attempt to investigate the pathogenicity of CNVs in chromosome Xp22.31 was explored.MethodsG-banding and SNP-array techniques were used to analyze chromosome karyotypes and CNVs in fetuses. Parents associate with five different pedigrees possessing high risk factors in pregnancy were considered with such parameters as advanced age, high risk of serological screening and ultrasound abnormalities.ResultsThe fetuses’ amniotic fluid karyotypes were 46, XX and those of their parents with the five pedigrees revealed no abnormalities. Here, we noticed a series of individuals with Xp22.31 duplications ranging from 534.6 kb to 1.6 Mb. It was detected through SNP array that the fetuses in Pedigree 1 and 2 had ~ 600 kb duplications in the Xp22.31 region of their X chromosomes which contained two OMIM genes, HDHD1 (OMIM: 306480) and part of STS (OMIM: 300747). The fetuses of Pedigrees 3, 4 and 5 had 1.6 Mb duplication in the same chromosome which contained four OMIM genes: HDHD1 (OMIM: 306480), STS (OMIM: 300747), PNPLA4 (OMIM: 300102) and VCX (OMIM: 300229). The duplications in the fetuses of Pedigrees 1 and 5 were inherited from the non-phenotypic parents. Pedigrees 3 and 4 refused to perform parental verification. Finally, four of the five pedigrees continue towards pregnancy with no abnormalities being observed during followed-ups.ConclusionOur study first showed duplications of Xp22.31 in Chinese population. Clinical and genetic investigation on five different pedigrees, we consider the duplication of these fragments as likely benign copy number variants (CNVs). We suggest that the duplications of Xp22.31 with recurrent duplication as a benign CNVs .

Exome Sequencing Identifies RET Associated Hirschsprung Disease in a Fetus with Echogenic Bowel

AbstractThis is report of a case of RET associated Hirschsprung disease in a fetus diagnosed using exome sequencing. The fetus initially presented with echogenic bowel at 16 weeks with maternal first trimester serum screen showing increased risk for Trisomy 21. Amniotic fluid karyotype, ΔF508 CFTR genotype and maternal TORCH serology were normal. Subsequent ultrasonograms showed dilated bowel loops, predominantly large bowel. Following delivery at 24 weeks, a post-mortem examination was performed. Dilated bowel was confirmed with no structural gut abnormality and no other dysmorphic finding. Histopathology revealed agangliosis confirming a diagnosis of Hirschsprung disease. Exome sequencing done on fetal DNA from amniotic fluid revealed a putative pathogenic heterozygous c.1438G &gt; A variant in exon 7 of RET gene, which was inherited from the asymptomatic mother. This enabled genetic counseling and prenatal diagnosis in subsequent pregnancy.

Mapping allele with resolved carrier status of Robertsonian and reciprocal translocation in human preimplantation embryos

Introduction Reciprocal translocations (RecT) and Robertsonian translocations (RobT) are among the most common chromosomal abnormalities that cause infertility and birth defects. Preimplantation genetic testing for aneuploidy using comprehensive chromosome screening for in vitro fertilization enables embryo selection with balanced chromosomal ploidy. However, it is normally unable to determine whether an embryo is a translocation carrier. We have reported a method named “Mapping Allele with Resolved Carrier Status” (MaReCs), which enables chromosomal ploidy screening and resolution of the translocation carrier status of the same embryo ( J. Xu et al. 2017 ). Here we introduce MaReCs and update the clinical study results. Material & Methods From September, 2017 to now, we have performed MaReCs on 69 patients, among them 55 were RecT carriers and 14 were RobT carriers. Result Totally 176 embryos from patients were identified ploidy-balanced, of which embryos from 41 patients were successfully identified as normal or balanced translocation. Other embryos’ translocation status could not be identified because of lacking reference embryos and these patients have accepted further identification in next cycles. And we have confirmed the accuracy of our carrier status determination in amniotic fluid karyotyping of seven cases as well as in the live birth we have thus far. Conclusions MaReCs accurately enables the selection of translocation-free embryos from patients carrying chromosomal translocations. It can work as an effective technology to help reduce the propagation of RecT/RobT in the human population.

A small supernumerary marker chromosome resulting in mosaic partial tetrasomy 4q26-q31.21 in a foetus with multiple congenital malformations

A parental diagnosis was performed for an unborn foetus of a healthy couple, who was due for ultrasound detection of multiple malformations and abnormal amniotic fluid karyotypes. For an accurate diagnosis, routine G-banding analysis and next generation sequencing (NGS) were carried out. Finally, conventional cytogenetic analysis suggested that the foetus had a karyotype of47,XX,+mar[52]/46,XN, meanwhile NGS also revealed a partial tetrasomy of 27.84Mb from 4q26-q31.21 (117,385,735-145,225,759), and G-banding analysis excluded the couple to have carried the 4q26-q31.21 duplication. We have identified a de novo mosaic small supernumerary marker chromosomes (sSMC) derived from 4q26-q31.21 in a foetus with hemivertebra, polydactyly, abnormal ears, and heart and ventricular septal defect.

Construction of amniotic cell line with chromosomal abnormalities and its application in the quality control of chromosome karyotype analysis

The aim of this study was to investigate the application of amniotic fluid cell lines with chromosomal abnormalities in the external quality assessment (EQA) of prenatal karyotype analysis. Simian virus 40 large T antigen (SV40LT) gene was transfected into amniotic fluid cells with 46,XY,t(15;17)(q11;q11) and 46,XY by liposome transfection. Control cell lines were produced by mixing the above two in ratios of 1:19, 1:1 and 9:1, respectively. The cells were then frozen at −30 °C, mailed between laboratories, prepared for chromosome analysis, photographed with karyotype, and evaluated. After the two amniotic fluid cell lines and the control cell lines were serially passaged for 10 generations, they were still spindle-shaped with adherent growth. The 46,XY,t(15;17)(q11;q11) line preserved the original amniotic fluid karyotype, whereas a small number of cells with 46,XY, had changes of chromosomal structure. After mailing between laboratories, the abnormal karyotype was scored to constitute, 10.8%, 54.2% and 81.2% on average in the 1:19, 1:1 and 9:1 samples, respectively. There were significant differences (P < 0.05) between the actual scores and the theoretically expected ones with respect to the controls with 5% and 90% abnormal karyotype, whereas no significant difference (P > 0.05) with respect to the ratio of 50%. Overall, we demonstrated that the SV40LT gene could immortalize amniotic fluid cells with chromosomal abnormalities. The immortalized cells with and without chromosomal abnormalities mixtured in different ratios could then serve as control cells in the EQA of prenatal karyotype analysis.

Mapping allele with resolved carrier status of Robertsonian and reciprocal translocation in human preimplantation embryos

Reciprocal translocations (RecT) and Robertsonian translocations (RobT) are among the most common chromosomal abnormalities that cause infertility and birth defects. Preimplantation genetic testing for aneuploidy using comprehensive chromosome screening for in vitro fertilization enables embryo selection with balanced chromosomal ploidy; however, it is normally unable to determine whether an embryo is a translocation carrier. Here we report a method named "Mapping Allele with Resolved Carrier Status" (MaReCs), which enables chromosomal ploidy screening and resolution of the translocation carrier status of the same embryo. We performed MaReCs on 108 embryos, of which 96 were from 13 RecT carriers and 12 were from three RobT carriers. Thirteen of the sixteen patients had at least one diploid embryo. We have confirmed the accuracy of our carrier status determination in amniotic fluid karyotyping of seven cases as well as in the live birth we have thus far. Therefore, MaReCs accurately enables the selection of translocation-free embryos from patients carrying chromosomal translocations. We expect MaReCs will help reduce the propagation of RecT/RobT in the human population.

Subjectivity in chromosome band–level estimation: a multicenter study

Chromosome band level is the primary quality indicator for G-banded metaphase chromosome analysis. Although current professional guidelines address the minimum necessary band level for constitutional studies, there is no study documenting the comparative performance of different band-level estimation methods. This study compared 5 band-level estimation methods (Stallard, Vancouver, Welborn, United Kingdom External Quality Assurance Scheme, and Ford) in a multicenter study in which 82 readers from 7 different clinical cytogenetics laboratories evaluated the same 10 karyotypes (5 from amniotic fluid and 5 from peripheral blood) by each method. There was a 94% correlation between the five band-level estimation methods. The Welborn method yielded significantly lower scores for amniotic fluid karyotypes (P < 0.01) but not for peripheral blood karyotypes (P = 0.75). The distribution of scores obtained from different readers suggests a high level of subjectivity in chromosome band-level assessment. The variation in band-level estimation did not correlate with reader experience or study center, except for readers from one laboratory, for which the distribution of scores was significantly lower (P < 0.01). The results from this study suggest that the consistent use of one method is more important than the actual method employed for monitoring karyotype quality.

Fetoplacental Discrepancy with Normal Karyotype in Amniotic Fluid and Two Different Cell Lines in Placenta

We present a case of fetoplacental discrepancy in a second-trimester fetus with normal karyotype in amniotic fluid and two different Robertsonian translocations in placenta. A 41-year-old woman of Middle-Eastern origin, gravida 2, para 1, underwent amniocentesis at 16-week gestation because of advanced maternal age. Amniotic fluid karyotype showed a normal 46,XX karyotype with a homozygous inv(9). Parental chromosome analysis showed both parents to be carriers of inv(9) and the parents are not consanguineous. Fetal ultrasound was normal. The mother presented to the clinic 4 weeks later with intrauterine fetal demise. Chromosome analysis from the placenta showed two different cell lines: a balanced (15;21) Roberstonian translocation in 11 cells and an unbalanced (21;21) Robertsonian translocation in 9 cells. The karyotype was interpreted as mos 45,XX,inv(9)(p11q13)x2,der(15;21)(q10;q10)[11]/46,XX,inv(9)(p11q13)x2,+21,der(21;21)(q10;q10). Mother was a carrier for the Cystic Fibrosis (delta F508), Factor V Leiden mutations, HbD-Los Angeles and HbQ-India variants. She also had a sibling with term stillbirth. Her husband's history was unremarkable. Our case appears to be another example of confined placental mosaicism (CPM) with normal fetal karyotype. However, we could not confirm the possibility that CPM contributed to the IUFD in our case given the complex medical history of the mother.

When are amniotic fluid viral PCR studies indicated in prenatal diagnosis?

To determine which prenatal ultrasound findings indicate the need to also obtain PCR studies for viral genome in women undergoing midtrimester amniocentesis. This was a retrospective observational study on women that underwent amniotic fluid karyotyping and viral PCR testing for history or ultrasound based indication. Amniotic fluid was tested for adenovirus, cytomegalovirus, respiratory syncytial virus, enterovirus, Epstein-Barr virus, and parvovirus B19 using multiplex PCR study with multiple appropriate controls. Ultrasound findings were coded as normal or abnormal with 34 categories of ultrasound abnormality stratified into 18 subgroups. Relationships between these subgroups and karyotype/PCR results were tested by Pearson chi-square method or Fisher's exact test and overall logistic regression analysis. Amniotic fluid samples from 1191 patients were obtained for the study. Abnormal karyotype was detected in 5.4% of cases (64/1191), and PCR was positive in 6.5% of cases (77/1191). Abnormal fetal ultrasonographic findings were observed in 28.4% of cases (338/1191). There was an association between intrauterine growth restriction, nonimmune hydrops fetalis, hand/foot anomalies or neural tube defects (NTDs), and PCR positivity. NTDs were associated with PCR positivity in fetuses with normal karyotype and nuchal thickening, cardiac or ventral wall defects were specifically associated with aneuploidy. Amniotic fluid viral PCR testing should be considered for fetuses with intrauterine growth restriction, nonimmune hydrops fetalis, hand/foot anomalies, or NTDs. After aneuploidy is excluded, NTDs are associated with PCR positivity.

Successful prenatal diagnosis following elimination of maternal cell contamination in a family with recessive dystrophic epidermolysis bullosa.

Objective To perform a DNA-based prenatal diagnosis in a family with recessive dys-trophic epidermolysis bullosa, and to develop a strategy to eliminate maternal cell contamination in amniotic fluid samples. Methods Amniocentesis was carried out at gestation week 16, amniotic fluid culture was used to separate fetal cells from maternal blood cells. Peripheral blood was obtained from the proband, and her parents. Genomic DNA was extracted from peripheral blood and aminotic cells. Subsequently, PCR and direct sequencing were performed to detect pathogenic mutations in the COL7A1 gene. Karyotype analysis was used to confirm paternal information in amniotic fluid. Linkage analysis between micro-satellite markers was performed to confirm the fetal genotype. Results Centrifugation showed visible contamination of aminotic cells by blood cells. Direct sequencing revealed that the proband was a carrier of both maternal mutation, R525X in exon 12, and paternal mutation, R2610X in exon 105, while the fetus only carried the maternal mutation, R525X. The second direct sequencing and haplotype analysis after elimination of mater-nal blood cells by amniotic fluid culture confirmed that the fetus was a carrier of maternal mutation with nor-mal phenotype. The pregnancy continued and a clinically unaffected girl was born at gestation week 40. Conclusion The accuracy of DNA-based prenatal diagnosis could be improved by the combination of direct sequencing, amniotic fluid culture, karyotype analysis and linkage analysis, etc. Key words: Epidermolysis bullosa dystrophica; Prenatal diagnosis

Duodenal atresia in an infant with triple‐X syndrome: A new associated malformation in 47,XXX

An association between the triple-X syndrome (47,XXX) and gastrointestinal malformations is extremely rare. Most 47,XXX patients present with a normal phenotype, but genitourinary malformations have been described. We report a case of a child with 47,XXX and duodenal atresia. Antenatal ultrasound scan showed a dilated fetal stomach and upper part of the duodenum (double bubble phenomenon) at 31 weeks of gestation in a 31-year-old woman with polyhydramnion. The amniotic fluid karyotype showed 47,XXX. After a scheduled delivery, duodenal atresia was confirmed and treated with duodeno-duodenostomy. The possible association of gastrointestinal and genitourinary tract anomalies requires a detailed postnatal clinical investigation and ultrasonographic examination of the abdomen, retroperitoneum, and pelvis on all triple-X syndrome patients.

Prenatal diagnosis of a mosaic supernumerary marker iso (8p) (tetrasomy 8p): discordance between chorionic villi culture and amniotic fluid karyotypes

We describe the first case of mosaic supernumerary marker iso (8p) displaying a karyotype discordance between chorionic villi (CV) and amniotic fluid (AF) cultures during prenatal cytogenetic diagnosis. In the first trimester, cytogenetic analysis after chorionic villi sampling (CVS) was normal in all metaphases in the short-term cytotrophoblast cell culture, but an undefined supernumerary marker was detected in 60% of mesenchymal cells in the long-term CV culture. Informed of the mosaicism, the couple selected amniotic fluid sampling as a second-trimester confirmatory diagnostic procedure. The supernumerary marker was absent in all of the 25 available AF cells metaphases. The prospective parents received genetic counselling and were informed that the discordance could be interpreted as a placental confined mosaicism or as a true foetal mosaicism with low percentage of affected cells. The couple opted to continue the pregnancy. In the second month of life, the child had abnormal development with severe psychomotor delay and frequent episodes of epilepsy. Postnatal cytogenetic extensive re-evaluation discovered that the previously detected supernumerary marker was indeed an isochromosome (8p) rearrangement present at low frequency in 5% of the blood lymphocytes.