Prenatal diagnosis of a fetus with mosaic ring chromosome 13: Case report and review of the literature.

OBJECTIVE: To diagnose the ring chromosome 13 (r(13)) in a fetus, and analyze the genotype-phenotype correlation. CASE REPORT: A 26-year-old woman who was second pregnancy, underwent amniocentesis at 18 weeks of gestation because of the increased nuchal translucency (NT). Prenatal ultrasound showed the NT thickness was 3.5 mm at 12+1 weeks of gestation and nuchal fold (NF) was 6.1 mm at 18 weeks of gestation, and amniotic fluid karyotype analysis revealed mosaic r(13). CMA detected a 16.293 Mb duplication at 13q21.32q31.1 and 31.303 Mb deletion at 13q31.1q34. CONCLUSION: R(13) is a very rare chromosomal abnormality. Cytogenetic examination combined with CMA can provide accurate diagnosis and effective information for genetic counseling.

Clinical Application of Chromosomal Microarray Analysis in Pregnant Women with Advanced Maternal Age and Fetuses with Ultrasonographic Soft Markers.

BACKGROUND In pregnant women with advanced maternal age (AMA) and fetuses with ultrasonographic (USG) soft markers it is always challenging to decide whether to implement chromosomal microarray analysis (CMA) or not. It is unclear whether CMA should be used in the fetuses with isolated USG soft markers, and there is still a lack of extensive sample research. MATERIAL AND METHODS We enrolled 1521 cases in our research and divided them into 3 groups as follows: pregnant women with isolated AMA (group 1, n=633), pregnant women whose fetuses had isolated USG soft markers (group 2, n=750), and pregnant women with AMA whose fetuses had isolated USG soft markers (group 3, n=138). All pregnant women underwent prenatal ultrasound and amniocentesis, and fetal cells in the amniotic fluid were used for genetic analysis of CMA. All participants signed a written informed consent prior to CMA. RESULTS Abnormal findings were detected by CMA in 330 (21.70%) fetuses, including 37 (2.43%) clinically significant copy number variations (CNVs), 52 (3.42%) benign or likely benign CNVs, and 240 (15.78%) variants of unknown significance. The frequency of clinically significant CNVs in group 1 and group 2 were significantly lower than that in group 3 (2.37% and 2.0% vs 5.07%, P<0.01). More than a half (59.46%, 22/37) of the pregnant women decided to continue their pregnancy despite having a fetus diagnosed with clinically significant CNV. CONCLUSIONS CMA can increase the diagnostic yield of fetal chromosomal abnormality for pregnant women with isolated AMA or/and their fetuses had isolated USG soft markers.

Frequency and clinical manifestation of prenatal cytogenetic diagnosis of chromosomal polymorphisms in Northeast China.

OBJECTIVE: To retrospectively analyze the incidence of chromosomal polymorphisms in prenatal cytogenetic diagnostic cases and the effect of the clinical manifestation of these fetuses. MATERIALS AND METHODS: 490 fetuses with chromosomal polymorphisms among 9996 pregnant women who underwent prenatal cytogenetic diagnosis were included in this study and were set as group 1. Other 500 pregnant women, whose fetuses were with normal karyotypes, were randomly selected from the remaining pregnant women and set as group 2. Clinical information and outcomes and maternal serum screening results of group 1 were compared with group 2. RESULTS: The frequency of fetal chromosomal polymorphism was 4.90% (490/9996). The most common variants observed were 1/9/16 qh± (2.27%, 227/9996), followed by inv(9) (0.90%, 90/9996). 94.62% (264/279) of fetal chromosomal variants were inherited from parents. No statistical difference was found in clinical information and outcomes and maternal serum screening results between group 1 and group 2. CONCLUSION: The fetus with chromosomal polymorphism has no impact on serum markers of second trimester screening and does not play an important role for the clinical outcome of the current pregnancy either, whether it is inherited from the parents or a de novo mutation.

Indigenization of the median of markers for Down syndrome screening based on statistical analysis of medical big data.

OBJECTIVE: To indigenize the median of Down syndrome (DS) screening markers for first and second trimester, and compare the impact of the indigenized and built-in median data on the efficiency of DS screening. MATERIALS AND METHODS: Data derived from first and Second-trimester screening (FTS and STS) for DS, composed of selected pregnancies deemed to be normal, were examined in a retrospective study. Indigenization regression analysis was calculated by using five models to fit statistical the raw data. Multiple of median (MoM) values estimated by using indigenized medians were compared with those calculated by using built-in. RESULTS: This study established a regression equation which is more suitable for the median of each screening marker in the local pregnant women. The changes of median MoM of screening markers were statistically significant after indigenization. For FTS, the detection rate was 100% when the false positive rate was 5%, and the cut-off value was 1/262. On the other hand, for STS, the detection rate of the model with indigenized parameters was 77.42%, which is 16.13% higher than that of built-in parameters. CONCLUSION: For the individual specific risk of pregnancy, when the indigenized parameters was used to calculate, is more accurately and screening effectiveness has been improved. This is a great reference significance for the current prenatal screening whether indigenized data should be used.

Prenatal diagnosis of a de novo tetrasomy 15q24.3-25.3: Case report and literature review.

BACKGROUND: Terminal duplication on chromosome 15q is a rare chromosomal variation. Affected individuals show similar features such as growth dysplasia or the development of frontal bossing, body deformities, facial abnormalities, and genitourinary or cardiovascular disorders. However, it is not yet clear whether such 15q repeats lead to identifiable patterns of clinical abnormalities. Therefore, the purpose of this study was to analyze the prenatal diagnostic results and clinical manifestations of a fetus with 15q duplication and to summarize the literature. METHODS: The case was a fetus at 28 weeks of gestation. The risk of Down syndrome from second-trimester screening was 1/140. Prenatal ultrasound and amniocentesis were performed, and chromosomal microarray analysis (CMA) was used for genetic analysis. RESULTS: The fetus had abnormal clinical features, including intracardiac echogenic focus in the left ventricle, an aberrant right subclavian artery, and growth delay. The fetal chromosomal karyotype was 46,XX,15q?,12q?,21pstk+, and CMA revealed a 10.163 Mb duplication at 15q24.3-q25.3. The couple chose to terminate the pregnancy after careful consideration. CONCLUSIONS: The combination and rational application of cytogenetics technology and molecular genetics technology such as CMA will open up the field of clinical application and provide useful genetic counseling for parents of fetuses carrying such chromosomal duplications.

[Predictive value of abnormal second-trimester maternal serum triple screening markers for adverse pregnancy outcomes].

OBJECTIVE: To investigate the predictive value of abnormal multiples of the median (MoM) of second trimester maternal serum triple screening (STMSTS) markers for adverse pregnancy outcomes. METHODS: 16 000 singleton pregnancies at 15⁺° to 20⁺5 weeks' gestation who underwent STMSTS between July 2010 and January 2013 in the First Hospital of Jilin University were recruited. Maternal serum AFP, free ß-hCG (F-ß-hCG) and unconjugated estriol (uE3) levels were measured using time- resolved fluoroimmunoassay, and then converted to MoM. LifeCycle 3.2 software was used to calculate risk, and a risk value greater than 1 in 270 or 1 in 350 was considered as high risk for trisomy 21 syndrome (Down syndrome, DS) and trisomy 18 syndrome (Edwards syndrome, ES), respectively. MoM of AFP more than 2.5 was considered high risk for open neural tube defect (ONTD). Amniocentesis and karyotyping, ultrasound screening were advised for high risk women. AFP, F-ß-hCG higher than 2.0 MoM or uE3 lower than 0.5 MoM was considered as abnormal, respectively. The MoM of STMSTS marker between women with adverse pregnancy outcome and with normal outcome was compared. RESULTS: (1) The median MoM of AFP, F-ß-hCG and uE3 was 0.91 MoM, 0.94 MoM and 1.05 MoM, respectively. Of the 16 000 pregnant women, there was no statistical difference in the median MoM of triple screening marker at different weeks of gestation (P > 0.05). The positive rate of DS, ES and ONTD in women ≤35 years old (n = 14 972) was 4.03% (603/14 972), 0.36% (54/14 972) and 0.29% (44/14 972) respectively. And in women>35 years old (n = 1 028), the positive rate was 24.51% (252/1 028), 1.95% (20/1 028) and 0.78% (8/1 028), respectively. There was a statistically significant difference of positive rate between the two groups (P < 0.05). (2) 9 cases of DS, 1 case of ES and 1 case of ONTD were found in the high risk group, and 2 cases of DS in the low risk group. The detection rate of DS, ES and ONTD was 9/11, 1/1 and 1/1 respectively; and the positive predictive value was 1.05% (9/855), 1.35% (1/74) and 1.92% (1/52), respectively. (3)The incidence of adverse outcome (group 1) was 1.49 % ( 239/16 000). 7 760 pregnant women in this study were healthy during pregnancy, so were their fetuses (group 2). There were significant differences in the age at delivery, body weight and markers' MoM of STMSTS between the two groups (P < 0.01). (4) In group 1, the rate of abnormal MoM of AFP or F-ß-hCG was 7.95% (19/239) and 23.85% (57/239), and the abnormal rate of MoM of uE3 was 4.18% (10/239). The rate of two abnormal MoM of markers was 5.02% (12/239); the rate that all three MoM were abnormal was 0.84% (2/239). However, in group 2, the rate of two abnormal MoM of markers was 0.14 % ( 11/7 760); and the rate that all three MoM were abnormal was 0. There was a significant difference of abnormal MoM of maternal serum marker between the two groups (P < 0.01). CONCLUSIONS: There is a relationship between abnormal marker of STMSTS and adverse outcomes. STMSTS show a high value in the detection of DS, ES and ONTD.