Study on clinical features and diagnostic methods of prenatal Wolf-Hirschhorn syndrome / 中华医学遗传学杂志

OBJECTIVE@#To investigate the clinical features of fetuses with Wolf-Hirschhorn syndrome(WHS) and explore the diagnostic methods and prenatal ultrasound characteristics and provide evidence for prenatal genetic counseling.@*METHODS@#We retrospectively analyzed 5 cases of WHS fetuses diagnosed from March 2016 to February 2020, and analyzed the results of chromosomal karyotype analysis and chromosomal microarray analysis (CMA) of the fetuses.@*RESULTS@#Five cases of WHS were detected by CMA, four cases were detected by karyotype analysis. Prenatal ultrasound revealed 4 abnormalities, of which 3 had intrauterine growth restriction, and only 1 had abnormalities of the maxillofacial region. The sequence of the fragments was 4p16.3p16.1 with a loss of 6.5 Mb, 4p16.3p15.32 with a loss of 15.6 Mb combined with 2p25.3 increased by 906kb, 4p16.3p15.31 with a loss of 20.4 Mb, 4p16.p15.1 with a loss of 35 Mb and 4p16.3p14 with a loss of 37 Mb.@*CONCLUSION@#Fetal growth restriction may be one of the early manifestations of WHS. Absence of fetal facial abnormality by prenatal ultrasound screening cannot exclude WHS. Karyotype analysis may miss the diagnosis of WHS, while combined CMA techniques can improve the diagnostic accuracy.

Prenatal diagnosis of five fetuses with 7q11.23 microdeletion or microduplication / 中华医学遗传学杂志

OBJECTIVE@#To investigate the ultrasonographic findings and genetic testing methods for fetuses carrying copy number variants (CNVs) of 7q11.23 region.@*METHODS@#Prenatal cases with 7q11.23 microdeletion/microduplication detected by single nucleotide polymorphism array (SNP array) from January 2016 to June 2020 were retrospectively analyzed, including fetal ultrasound, chromosomal karyotype, SNP array, pregnancy outcome and follow-up. Literature on 7q11.23 CNVs identified upon prenatal diagnosis was also reviewed.@*RESULTS@#Five fetuses were found with 7q11.23 CNVs, including 3 microdeletions and 2 microduplications. Of them, 4 had ultrasonographic anomalies. The karyotypes of all fetuses were normal. Of three 7q11.23 microdeletions, two were de novo, while the remaining one couple did not accept parental verification. Of two 7q11.23 microduplications, one was de novo and the another was inherited from a phenotypic normal father. Three 7q11.23 microdeletions and one de novo 7q11.23 microduplication were electively aborted. One fetus carrying paternally inherited 7q11.23 microduplication was delivered full term. Follow-up found the infant had a normal phenotype.@*CONCLUSION@#Fetuses with 7q11.23 microdeletions or microduplications showed phenotypic heterogeneity. SNP array can accurately detect 7q11.23 CNVs, thereby provide accurate information for prenatal diagnosis and genetic counseling.

Impact of confined placental mosaicism on non-invasive prenatal testing and pregnancy outcomes / 中华医学遗传学杂志

OBJECTIVE@#To assess the impact of confined placental mosaicism (CPM) on non-invasive prenatal testing (NIPT) and pregnancy outcomes.@*METHODS@#Copy number variation sequencing (CNV-seq) and single nucleotide polymorphism array (SNP-array) were carried out on placental specimen sampled from eight pregnancies with confirmed false-positive NIPT results. The impact of CPM on NIPT and pregnancy outcomes were analyzed based on the laboratory tests and clinical characteristics.@*RESULTS@#Five of the eight cases with false-positive NIPT results were proven to be CPM involving trisomy 9, 13, 21, 22, and X, respectively. The mosaic ratios for different placental regions have varied from 4% to 80%. Two fetuses with confirmed CPM showed fetal growth restriction (FGR) and additional ultrasound abnormalities, 1 fetus showed only FGR. The remaining two fetuses showed normal growth.@*CONCLUSION@#NIPT is highly sensitive to CPM, whilst CPM is an important cause for false-positive NIPT result. CPM may be associated with FGR. Investigation of the presence of CPM is important for both pre- and post-test genetic counseling and management of the pregnancy.

Effectiveness of non-invasive prenatal screening for the detection of fetal sex chromosome anomalies / 中华医学遗传学杂志

OBJECTIVE@#To evaluate the efficacy of non-invasive prenatal screening (NIPS) for fetal sex chromosome anomalies.@*METHODS@#A retrospective analysis was carried out for 20 802 women undergoing NIPS screening. For 165 cases suspected for fetal sex chromosomal anomalies, the results of invasive prenatal diagnosis were obtained.@*RESULTS@#Among the 165 cases suspected for fetal sex chromosome anomalies, 129 have accepted invasive prenatal diagnosis, and 45 were confirmed, which yielded a positive predictive value of 34.88%. These included 16 cases of 47,XYY, 10 cases of 47,XXY, 6 cases of 45,X/46,XX, 5 cases of 47,XXX, 3 cases of 45,X, 1 case of 45,X/46,X,i(X)(q10), 1 case of 45,X/46,X,del(X)(q22), 1 case of 46,X,del(X)(q22), 1 case of 46,X,del(X)(p11) and 1 case of Xp22.31 1.2 Mb deletion.@*CONCLUSION@#NIPS has limited value for detecting fetal sex chromosome anomalies. Karyotyping analysis combined with other diagnostic techniques can offer effective prenatal diagnosis for suspected cases.

Prenatal diagnosis and clinical analysis of two fetuses with Cat-eye syndrome / 中华医学遗传学杂志

OBJECTIVE@#To determine the origin of supernumerary small marker chromosomes (sSMCs) carried by two fetuses.@*METHODS@#Single nucleotide polymorphism array (SNP-array) and fluorescence in situ hybridization (FISH) analysis were carried out on cells cultured from the amniotic fluid samples.@*RESULTS@#SNP-array analysis showed both fetuses to be arr[hg19]22q11.1q11.21(16 888 899-18 649 190)×4, with a duplicated 1.7 Mb region (16 888 899-18 649 190) leading to partial tetrasomy of 22q11.1-22q11.21. FISH confirmed that both fetuses were 47,XN,+mar.ish idic(22)(q11.2) (RP11-958H20 ++),which suggested a diagnosis of Cat-eye syndrome (CES). The appearance of abortuses were consistent with the diagnosis of CES.@*CONCLUSION@#Two fetuses with CES were diagnosed by genetic testing. The latter has provided a basis for genetic counseling.

Ultrasound screening and clinical manifestations of congenital cytomegalovirus infection in fetuses / 中华围产医学杂志

Objective To investigate the value of ultrasound screening for congenital cytomegalovirus (CMV) infection in fetuses and to summarize the clinical manifestations.Methods From January 2012 to December 2017,we retrospectively analyzed the clinical data of 905 gravidas who received invasive prenatal diagnosis in Fujian Provincial Maternity and Children's Hospital for abnormal prenatal ultrasound findings including ventriculomegaly,intracranial calcification,microcephaly,echogenic bowel and fetal growth restriction (FGR).CMV DNA loads in amniotic fluid and neonatal urine were detected by real-time polymerase chain reaction.CMV-specific IgM and IgG in umbilical cord and neonatal peripheral blood were detected by commercial enzyme 1 inked immunosorbent assay kits.Eighteen fetuses with normal karyotype were diagnosed as congenital CMV infection.Relationships of ultrasound features and CMV DNA loads in amniotic fluid to pregnancy outcomes were analyzed with x2 test or Fisher's exact test.Results (1) Congenital CMV infection was detected in 18 fetuses in this study with an detection rate of 1.99％ (18/905).Three pregnancies were terminated immediately after the diagnosis was confirmed,two terminated when the ventriculomegaly progressed,five terminated for hydrocephaly and eight continued to delivery.(2) Congenital CMV infection rate was significantly higher in those with two or more ultrasound abnormalities than that in those with only one abnormal indicator [3.92％(8/204) vs 1.28％(9/701),x2=4.619,P=0.032].Fetuses with craniocerebral abnormalities were more likely to have congenital CMV infection than those without [3.11％(13/418) vs 0.82％(4/487),x2=6.392,P=0.012].(3) Among the 18 fetuses with congenital CMV infection,those with serious ultrasound abnormalities had a significantly higher rate of adverse outcomes than those without (11/11 vs 3/7,Fisher's exact test,bilateral P=0.043).No significant difference in the rate of adverse outcomes was found between fetuses with low and high CMV DNA loads in amniotic fluid (3/4 vs 12/14,Fisher's exact test,bilateral P=1.000).Conclusions Ultrasound abnormalities including ventriculomegaly,intracranial calcification,microcephaly,echogenic bowel and FGR,especially those with multiple abnormalities and brain abnormalities,increased risk of congenital CMV infection.Congenital CMV fetuses with serious ultrasound abnormalities has adverse outcomes.

The prevalence and genetic characterization of 22750 cases of beta-thalassemia in Fujian Province / 中华检验医学杂志

Objective To analyze the molecular characterization and prevalence of beta-thalassemia in Fujian Province .Methods RDBwas applied to identify 17 point mutations of beta gene and 3 point mutations of alpha gene .Gap-PCRwas applied to identify 3 deletions of alpha gene , MLPA and DNA sequecing were applied to identify the rare mutational genotype of beta-thalassemia.Results 3515 cases (15.45％)ofβ-thalassemia were confirmed.15 genotypes were found in the studied subjects .βIVS-2-654(C→T)/βN, βCD41-42(-TCTT)/βN, βCD17(A→T)/βN, β-28(A→G)/βN, βCD27-28( +C)/βN, and βCD26(G→A)/βN were the mostcommon genotypes in Fujian Province , accounting for 41.76％, 30.50％, 12.46％, 5.46％, 2.93％and 1.82％respectively , It was found that the total frequency of them was 94.93％in our study.13 cases of deletional β-thalassemia were detected , including 6 cases of Southeast Asia subtype ( SEA-HPFH) , 6 cases of Chinese subtype Gγ(Aγδβ)0 and 1 case of 1.35kb deletion(NG-000007.3:g.69997-71353 del 1357) in one subject .13 cases of rareβ-thalassemia were detected , including Hb J-Bankok in 8 subjects and Hb New York in 5 subjects were diagnosed .Conclusions As a high-risk area forβ-thalassaemia, the detection of deletional β-thalassemia and rare β-thalassaemia subtypes should be screened in addition to the common β-thalassemia genes , so as to demonstrate the results of β-thalassemia gene detection in this region .Those screening results are useful for genetic counseling and can effectively reduce the birth of children with moderate to severe β-thalassaemia .

Prenatal diagnosis of a fetus with Miller-Dieker syndrome / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To report on prenatal diagnosis of a fetus with Miller-Dieker syndrome (MDS) and explore its genotype - phenotype correlation.</p><p><b>METHODS</b>Chromosome karyotyping, bacterial artificial chromosome on beads (BACs-on-Beads, BoBs), fluorescence in situ hybridization (FISH), and single nucleotide polymorphism microarray (SNP array) were applied in conjunction for the prenatal diagnosis of a fetus with abnormal ultrasound findings.</p><p><b>RESULTS</b>A 17p13.3 microdeletion was detected with the BoBs assay, and the result was confirmed by FISH. With the SNP array, the deletion was mapped to chromosome 17, with its range determined to be 5.2 Mb. On high-resolution banding analysis and BoB assay, the deletion was not found in either parent.</p><p><b>CONCLUSION</b>The combined use of BoBs, FISH and SNP array has enabled prenatal diagnosis of a fetus with MDS. Attention should be paid to microdeletions and microduplications which can be missed by conventional chromosomal karyotyping analysis.</p>