Prenatal diagnosis for Walker-Warburg syndrome by whole exome sequencing / 临床检验杂志

Objective To perform prenatal diagnosis for a fetus with hydrocephalus and congenital heart disease by whole exome se-quencing ( WES) , and then provide genetic counseling for the next pregnancy. Methods DNAs from amniotic fluid cells of the fetus and peripheral blood of his/her parents were extracted, respectively, and then performed WES. After the process of library construc-tion, hybrid capture and sequencing, the obtained data were compared with the database from human genome and literatures and ana-lyzed by software. The pathogenic mutations were searched based on the American College of Medical Genetics and Genomics ( ACMG, 2015) guideline and verified by the Sanger sequencing. Results The WES results found that the compound heterozygous mutations ex-isted in POMT1 gene of the fetus, which were inherited from the splice site mutation c.605+1G>A( IVS7) of his/her mother and the frameshift mutation c.1367 c.1368 ( exon 15) insGA, p. L456Lfs?80 of his/her father, respectively. The Sanger sequencing results were consistent with that of WES. The fetus was affected by Walker-Warburg syndrome, and his/her parents decided to terminate the pregnancy finally. Conclusion The WES may diagnose Walker-Warburg syndrome rapidly and accurately, which may play an impor-tant role in clinical management and genetic counseling.

Genetic analysis and prenatal diagnosis for 25 Chinese pedigrees affected with congenital adrenal hyperplasia due to 21-hydroxylase deficiency / 中华医学遗传学杂志

OBJECTIVE@#To identify pathogenic mutations in 25 Chinese pedigrees affected with congenital adrenal hyperplasia (CAH).@*METHODS@#Mutations of the CYP21A2 gene were detected with locus-specific PCR/restriction endonuclease analysis, multiplex ligation-dependent probe amplification assay, and direct sequencing of the entire CYP21A2 gene. Prenatal diagnosis was offered to fetuses at risk for CAH.@*RESULTS@#All 50 alleles of the CYP21A2 gene carried by the 25 pedigrees were successfully delineated. Large deletions and conversions have accounted for 16 (32%) of the alleles, which included 9 entire CYP21A2 gene deletions, 6 chimeric CYP21A1P/CYP21A2 genes, and 1 partial conversion of the CYP21A2 gene. For the remaining 34 alleles, there were 9 micro-conversions and 4 de novo mutations [including a previously unreported c.62G>A (p.Trp21X) mutation]. Prenatal diagnosis was provided for 28 fetuses with a high risk for CAH, among whom 8 were found to be affected.@*CONCLUSION@#The detection of CYP21A2 gene mutations can facilitate appropriate genetic counseling and prenatal diagnosis for the affected pedigrees.

Prenatal diagnosis of two fetuses with chromosome 1p36 deletion syndrome / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze two fetuses with multiple malformations revealed by ultrasonography using single nucleotide polymorphism array (SNP array), and to explore the strategy for the prenatal diagnosis of 1p36 deletion syndrome.</p><p><b>METHODS</b>Amniocentesis was performed on the two pregnant women. Amnion fluid cells were cultured, and karyotypes of the fetuses were determined through G-banding analysis. Whole genome SNP array was used to detect genomic anomalies of the two fetuses. The karyotypes of their parents were determined through G-banding analysis of peripheral venous blood samples.</p><p><b>RESULTS</b>G-banding analysis showed a 46,XY,add(1p36)? and a 46,XX,add(1p36)? karyotype for fetuses 1 and 2, respectively. SNP array analysis showed that the fetus 1 had arr[19]1p36.33p36.32 (752 566 - 3 393 462)×1 and 7q35q36.3 (144 480 549 - 159 119 486)×3, and fetus 2 had arr[19]1p36.33p36.23 (752 566 - 8 362 754)×1, 6p25.3p22.3 (204 909 - 20 182 185)×3. The mother of fetus 1 had a 46,XX,t(1;7)(p36;q35) karyotype, and the mother of fetus 2 had a 46,XX,t(1;6)(p36;p22) karyotype. The karyotypes of both fathers appeared to be normal.</p><p><b>CONCLUSION</b>SNP array has the advantages such as high sensitivity and high accuracy for prenatal diagnosis, and can provide more detailed information for genetic counseling of 1p36 deletion syndrome.</p>

Detection of TSC1/TSC2 gene mutations among patients with tuberous sclerosis complex by Ion Torrent semiconductor sequencing / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To develop and validate a method for mutation screening and prenatal diagnosis of TSC1/TSC2 mutations among patients with tuberous sclerosis complex (TSC) by Ion Torrent semiconductor sequencing.</p><p><b>METHODS</b>Potential mutations of SC1/TSC2 gene was detected in 2 TSC families and 1 sporadic TSC patient using an Ion Torrent PGM sequencer. Candidate variants were validated by Sanger sequencing. The corresponding site of TSC2 in the fetus of family 2 was also detected with Sanger sequencing.</p><p><b>RESULTS</b>Ion Torrent semiconductor sequencing has identified a probably pathogenic TSC2 mutation (c.311-312insGCTG) in the patient from family 1, and a probably pathogenic TSC2 mutation (c.1790A>G) in the patient of family 2.</p><p><b>CONCLUSION</b>Targeted Ion Torrent PGM sequencing is an accurate and efficient method to detect TSC1/TSC2 mutations in TSC.</p>

Development and application of molecular diagnostic method of hemophilia A / 中华检验医学杂志

Objective To develop and validate a method for detecting factor 8 gene (F8) mutations in hemophilia A patients by Ion Torrent semiconductor sequencing .Methods Intron 22 and intron 1 inversions of F8 gene were identified by long distance PCR (LD-PCR), other mutations in the F8 gene were identified by Ion Torrent sequencing.Candidate variants were validated by Sanger sequencing .Sanger sequencing was applied to screen HA carriers from 11 female family members in the 8 pedigrees.One pregnant woman was offered prenatal diagnosis via analyzing the fetal DNA obtained through amniocentesis . Results Four missense mutations ( c.1331A >C, 1648C >T, c.6506G >A, c.6544C >T), two frameshift mutations ( c.2393 _2394insT, c.6320delG), one splicing mutation ( IVS5 +5G >A), one nonsense mutation (c.43C >T) and one Inv22 mutation were identified in all nine probands respectively . Among 11 female family members, 10 females were identified to be HA carriers, and one didn′t carry the maternal pathogenic mutation.Prenatal diagnosis result showed that the fetus inherited the wild -type maternal allele and was predicted to be unaffected by HA .Conclusion The targeted Ion Torrent sequencing is a reliable and efficient method to detect F8 mutations in patients with Hemophilia A disease .

Application of multiplex ligation-dependent probe amplification for rapid detection of aneuploidies and structural chromosomal abnormalities in prenatal diagnosis / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the value of multiplex ligation-dependent probe amplification (MLPA) for rapid detection of aneuploidies and structural chromosomal abnormalities during prenatal diagnosis.</p><p><b>METHODS</b>Two hundred and eight six amniotic fluid samples were analyzed with both MLPA and conventional karyotyping. Structural abnormalities were verified with array comparative genomic hybridization.</p><p><b>RESULTS</b>Ten cases of trisomy 21, 2 cases of trisomy 18, 1 case of trisomy 13, 1 case of mosaic trisomy 21, 1 case of 45,X, 1 case of large deletion of Xp, 1 case of trisomy 18p and 1 case of large deletion of 18p and 18q were identified. The same results were derived by both MLPA and conventional karyotyping. Structural abnormalities were verified by array comparative genomic hybridization (aCGH) with 100% accuracy.</p><p><b>CONCLUSION</b>In addition to aneuploidies, MLPA can rapidly identify large deletions and duplications of chromosomes 21, 18, 13, X and Y. MLPA is supplementary to conventional karyotyping for identification of such chromosomal abnormalities prenatal diagnosis.</p>