Objective To estimate clinical application of multiplex ligation-dependent probe amplification (MLPA) for rapid prenatal detection of aneuploid abnormalities in amniotic fluid.Methods Totally 1229 amniotic fluid samples were collected from the pregnant women receving prenatal diagnosis for chromosomal abnormalities in Prenatal Diagnosis Center of Shenzhen Maternity and Child Healthcare Hospital from October 2009 to December 2010.All the samples were investigated independently with both MLPA and G-band karyotyping to detect aneuploidies of chromosomes X,Y,13,18 and 21.A comparison was followed the results acquired from two methods for evaluation of sensitivity and specificity of MLPA.ResultsThirtyeight aneuploidies were detected by G-band karyotyping,in which 34 were nonmosaic aneuploidies and 4were mosaic aneuploidies.MLPA and G-band karyotyping had consistent results in detecting the nonmosaic aneuploidies of chromosomes X,Y,13,18 and 21. Among 4 mosaic aneuploidies detected by G-band karyotyping,2 were confirmed by MLPA independently.Conclusions The sensitivity and specificity of MLPA in detecting the nonmosaic aneuploidies of chromosomes X,Y,13,18 and 21 were clinically acceptable.MLPA provides an efficient,reliable method for rapid detection of aneuploidies.

Objective To explore the value of chromosome microarray analysis (CMA) in determining the genetic etiology of fetuses with increased nuchal translucency (NT) but normal karyotype. Methods Amniocentesis, karyotype analysis and CMA were performed to singleton pregnant women with increased fetal NT ( ≥ 3.0 mm) in early pregnancy (11+1-13+6 gestational weeks) at Shenzhen Maternity and Child Healthcare Hospital from March 2015 to December 2017. A total of 339 fetuses with normal G banding karyotype analysis were recruited retrospectively. Peripheral blood samples were collected for CMA in parents whose fetuses were detected with pathogenic copy number variations (CNVs) or variants of uncertain significance (VUS). Descriptive analysis was used for CMA results. Moreover, Pregnancy outcomes and postnatal conditions of fetuses with abnormal CNVs were followed up. Results Pathogenic CNVs, ranging from 68 kb to 12.636 Mb, were detected in 15 out of the 339 fetuses (4.4%) including four microduplications and 11 microdeletions. Among them, there were eight known microdeletion or microduplication syndromes (nine cases) including Williams-Beuren syndrome, 18p deletion syndrome,Wolf-Hirschhorn syndrome, 22q11 duplication syndrome, 16p11.2 deletion syndrome, 17p13.3 duplication syndrome, 16p11.2 duplication syndrome (one case respectively) and DiGeorge syndrome/velocardiofacial syndrome (two cases). Of the 11 fetuses with VUS, five cases originated from parents with normal phenotype and the identified VUS were benign and the rest six were de novo mutations[1.8%(6/339)]. Of the 15 fetuses with pathogenic CNVs, one was lost to follow-up, four were live born and two of which was found to be growth retardation at the age of two. Among the 11 fetuses with VUS, nine were live born and no abnormality was reported in any cases at one year old. Conclusions For fetus with increased NT and normal karyotype, CMA is able to identify chromosomal microdeletion/microduplication that are not recognized by conventional karyotyping analysis, and may play an important role in prenatal diagnosis and genetic counseling.

Objective To explore the genetic characteristics of fetuses with congenital heart diseases(CHD)diagnosed by prenatal ultrasound.Methods Data of 613 singletons with prenatal ultrasonic diagnosed CHD were retrospectively analyzed.The cardiac structural abnormalities were classified into 8 types.Whole-exome sequencing(WES)was performed for 40 fetuses since chromosomal karyotyping analysis and/or chromosomal microarray analysis(CMA)showed benign copy number variations(CNV)or variants of uncertain significance(VUS).Results Among 613 fetuses,479 fetuses underwent both chromosomal karyotyping analysis and CMA,genomic abnormalities were detected in 60 fetuses(60/479,12.53％).Among 134 fetuses underwent only CMA,genomic abnormalities were found in 4 fetuses(4/134,2.99％).According to results of chromosomal karyotyping analysis and/or CMA,abnormalities were noticed in 40 fetuses(40/568,7.04％)among 568 fetuses with isolated CHD,while in 15 fetuses(15/45,33.33％)among 45 fetuses with non-isolated CHD,respectively.Abnormality detection rate of chromosomal karyotyping analysis and/or CMA in fetuses with complex CHD(10/41,24.39％)was higher than that in fetuses with non-complex CHD(54/572,9.44％).Among complex CHD fetuses,abnormality detection rate was the highest in fetuses with conotruncal defect(CTD)combined with malformation of venous system(4/13,30.77％),while among fetuses with non-complex CHD,situs inversus viscerum had the highest detection rate(1/4,25.00％).Among 40 fetuses chromosomal karyotyping analysis and/or CMA showed benign CNV or VUS,WES indicated pathogenic CNV/likely pathogenic CNV(P/LP)in 3 fetuses,VUS in 3 fetuses and benign CNV in 34 fetuses.Conclusion Fetuses with CHD,especially extracardiac malformations had possibilities of genomic abnormalities.Fetuses with CTD combined with malformation of venous system had higher possibilities of genomic abnormalities.Compared with CMA alone,chromosomal karyotyping analysis combined with CMA was helpful for detecting genomic abnormalities.

OBJECTIVE To provide prenatal diagnosis for families affected with tuberous sclerosis complex and explore the correlation between phenotype and genotype. METHODS For probands from 10 families, all exons and splicing regions of the TSC1 and TSC2 genes were analyzed with high throughput DNA sequencing. Suspected mutations were verified by Sanger sequencing. RESULTS All probands were found to have mutations, which included 1 case with TSC1 mutation and 9 cases with TSC2 mutations (missense mutations in 6, nonsense mutations in 2, and frameshifting mutation in 1 case). Prenatal diagnosis was provided for 9 cases, and 1 fetus was found to carry a mutation. Genetic analysis has identified a novel pathogenic mutation (TSC2 c.2415-2416 ins GT). CONCLUSION Identification of pathological mutations for tuberous sclerosis complex can facilitate genetic counseling and prenatal diagnosis for the affected families.

Objective:To explore the characteristics and diagnostic methods of Pierre Robin sequence in prenatal ultrasonography.Methods:The ultrasonographic features and pregnancy outcome were analyzed in 12 cases of fetuses with Pierre Robin sequence who were diagnosed by ultrasound prenatally in Shenzhen Maternity & Child Healthcare Hospital from 2017 January to 2020 January, and chromosome examination results were collected.Results:Prenatal ultrasonographic features of 12 cases of Pierre Robin sequence were characterized by micrognathia, incomplete cleft palate and tongue posture, among which 4 cases were isolated Pierre Robin sequence, 8 cases were combined with associated malformations, and 1 case of isolated Pierre Robin sequence was misdiagnosed.Conclusions:Fetus with Pierre Robin sequence has characteristic features in prenatal ultrasound, the facial median sagittal plane and oblique coronal plane of palate through oral cleft are contributive to its diagnosis.

Objective:To assess the ultrasonographic features and potential diseases of fetal abnormal sylvian fissure(SF), and to explore the value of whole-genome sequencing (WGS) in prenatal detection.Methods:A total of 28 fetuses with a sonographic diagnosis of abnormal SF in Shenzhen Maternal and Child Health Hospital Affiliated to Southern Medical University between October 2018 and October 2020 were prospectively included. The fetal brain was evaluated by neuroultrasound and intrauterine MRI in detail. Amniotic fluid/cord blood obtained by amniocentesis or tissue samples from umbilical cord after birth were collected for WGS. Pregnancy outcomes and postnatal MRI were recorded, and neurodevelopment of live-born infants was followed up for more than 24 months after delivery.Results:During the study period, 28 fetuses with abnormal SF were identified, with a gestational age of 21.3-30.0 (24.8±2.0) weeks. Abnormal SF presented in MCD ( n=15, 53.6%), chromosomal anomalies ( n=3, 10.7%) or single-gene genetic syndromes ( n=3, 10.7%) with the affected fetuses showing developmental delay, hydrocephalus or leukomalacia ( n=4, 14.2%), corpus callosal agenesis with large interhemispheric cysts ( n=1, 3.6%), benign subarachnoid space enlargement with arachnoid cysts ( n=1, 3.6%), and multiple malformations ( n=1, 3.6%). Among the 15 cases with MCD, the most common pathology was lissencephaly/pachygyria, followed by schizencephaly, severe microcephaly, hemimegalencephaly with paraventricular heterotopia, and polymicrogyria. Abnormal SF presented bilaterally in 23 fetuses and unilaterally in 5. All cases were categorized into six types depending on SF morphology in the transthalamic section: no plateau-like or a small insula, linear type, irregular corrugated SF, Z-shaped, and cyst occupying type. In addition to abnormal SF, associated anomalies or mild variations were identified in all fetuses. There were 17 cases underwent intrauterine MRI, and 13 cases underwent postnatal MRI examination.And 25 pregnancies were terminated; 3 were born alive, and 2 had typical syndromic changes with poor neurodevelopmental prognosis. A related pathogenic genetic variant was detected in 57.1% (16/28) fetus, and the incidence of single nucleotide variants(SNVs) was 42.9% (12/28), among which de novo SNVs accounted for 91.7% (11/12). Conclusions:Fetal abnormal SF could be classified based on the ultrasonographic features of transthalamic section. Fetal abnormal SF may indicate MCD, some chromosomal abnormalities or single-gene genetic syndromes that may lead to poor neurodevelopmental outcomes, and may be affected by extra-cortical factors. It is suggested to carry out targeted prenatal genetic diagnosis for fetuses with abnormal SF.