Prenatal diagnosis and pregnancy outcome of fetuses with rare autosomal trisomies indicated by non-invasive prenatal testing / 中华医学遗传学杂志

OBJECTIVE@#To analyze the result of prenatal diagnosis and outcome of pregnancy for fetuses with rare autosomal trisomies (RATs) suggested by non-invasive prenatal testing (NIPT).@*METHODS@#A total of 69 608 pregnant women who underwent NIPT at Genetics and Prenatal Diagnosis Center of the First Affiliated Hospital of Zhengzhou University from January 2016 to December 2020 were selected as study subjects. The result of prenatal diagnosis and outcome of pregnancy for those with a high risk for RATs were retrospectively analyzed.@*RESULTS@#Among the 69 608 pregnant women, the positive rate of NIPT for high-risk RATs was 0.23% (161/69 608), with trisomy 7 (17.4%, 28/161) and trisomy 8 (12.4%, 20/161) being the most common, and trisomy 17 (0.6%, 1/161) being the rarest. For 98 women who had accepted invasive prenatal diagnosis, 12 fetal chromosomal abnormalities were confirmed, and in 5 cases the results were consistent with those of NIPT, which yielded a positive predictive value of 5.26%. Among the 161 women with a high risk for RATs, 153 (95%) were successfully followed up. 139 fetuses were ultimately born, with only one being clinically abnormal.@*CONCLUSION@#Most women with a high risk for RATs by NIPT have good pregnancy outcomes. Invasive prenatal diagnosis or serial ultrasonography to monitor fetal growth, instead of direct termination of pregnancy, is recommended.

Genetic diagnosis of non-classical 21-hydroxylase deficiency by the new nanopore sequencing detection method / 中华检验医学杂志

Objective:To summarize initial experience of applying nanopore third-generation sequencing detection method (nanopore sequencing) for genetic diagnosis of non-classical 21 hydroxylase deficiency (NC 21-OHD), and to explore its performance and application prospects.Methods:Clinical data of the two NC 21-OHD patients, who were hospitalized at the First Affiliated Hospital of Zhengzhou University in May 2019, were collected. Peripheral venous blood was collected and genome DNA extracted. Genetic variants was detected by nanopore sequencing and underwent bioinformatic analysis. Pathogenetic mutations in CYP21A2 gene were validated with PCR-sanger sequencing in the two patients and their parents.Results:The average reads length and sequence depth in the patient one was 12, 792 bp and 27.19×. The average reads length and sequence depth in the patient two was 13, 123 bp and 21.34×. Compound variants of c.293-13C>G/c.844G>T (p.Val282Leu) and c.332_339delGAGACTAC (p.Gly111Valfs)/c.844G>T (p.Val282Leu) were detected in these two patients, which were consistent with clinical phenotype of NC 21-OHD. Further analysis showed that c.293-13C>G mutation was inherited from her father and c.844G>T (p.Val282Leu) mutation was inherited from her mother for the patient one. The c.844G>T (p.Val282Leu) mutation was inherited from her father and c.332_339delGAGACTAC (p.Gly111Valfs) mutation from her mother.Conclusions:The heterozygous mutations in CYP21A2 gene are the cause of NC 21-OHD in these two patients. Nanopore sequencing technique is a reliable new detection method for patients with NC 21-OHD.

Clinical and genetic features of 5 alpha-reductase type2 deficiency caused by SRD5A2 gene variants / 中华内分泌代谢杂志

Objective:To explore the clinical and genetic characteristics of 5α-reductase 2 deficiency syndrome(5α-RD2).Methods:Retrospective analysis of three cases of 5α-RD2 to summarize clinical data. Genetic testing was conducted using chromosome karyotyping analysis, whole-exome sequencing(WES), Sanger sequencing, and bioinformatics analysis. The effect of the novel variant on the structure of the 5α-reductase was evaluated by studying the homology modeling structure using SWISSMODEL and PyMoL.Results:The patients of all three cases have social gender as female. In Case 1, a 6-year-old patient sought medical attention due to abnormal external genitalia development. In Cases 2 and 3, 15-year-old patients presented with primary amenorrhea, and they showed masculinization of secondary sexual characteristics during puberty. In all three cases, the external genitalia exhibited varying degrees of masculinization, with clitoromegaly resembling a small penis and accompanying cryptorchidism. In Case 2, an hCG stimulation test was performed, and the testosterone/dihydrotestosterone(DHT) ratio was found to be 17.4. The karyotype of all three patients was 46, XY. Whole-exome sequencing(WES) detected SRD5A2 gene variants in all cases, with genotypes being p. Gln6Ter/p.Arg227Gln, p. Gln6Ter/p.Pro250Ala, and p. Arg227Ter/p.His89Tyr, respectively. Parental validation confirmed compound heterozygous mutations in all cases. The novel variant p. Pro250Ala was identified and classified as a likely pathogenic variant according to ACMG guidelines. Protein modeling analysis indicated that this variant may affect the binding of 5α-reductase 2 to NADPH. In Case 1, male gender was chosen, and a laparoscopic bilateral orchiopexy was performed. In Case 2, female gender was chosen, and testectomy and vaginoplasty were performed. The gender selection for Case 3 has not been definitively determined yet.Conclusions:Abnormal external genitalia is a common phenotype of 5α-RD2. After hCG stimulation test, there is a significant increase in the testosterone/dihydrotestosterone(DHT) ratio, which indicates that Sanger sequencing of the SRD5A2 gene can be directly performed. 5α-RD2 exhibits significant clinical heterogeneity, and WES can facilitate the differential diagnosis of 46, XY disorders of sex development. The study also reported a novel variant, p. Pro250Ala, which enriches the SRD5A2 gene variant database.

Genetic analysis of a pregnant woman with moderate intellectual disability due to variant of DLG4 gene / 中华医学遗传学杂志

OBJECTIVE@#To carry out genetic testing and prenatal diagnosis for a woman featuring moderate intellectual disability (ID).@*METHODS@#The patient had presented at the First Affiliated Hospital of Zhengzhou University on April 28, 2021. With informed consent, peripheral blood and amniotic fluid samples were collected for the extraction of genomic DNA. Pathogenic copy number variations (CNVs) were detected with CNV-seq, and single gene variants were detected by whole exome sequencing (WES) and Sanger sequencing. Candidate variant was verified by Sanger sequencing, and CNV-seq and multiplex ligation-dependent probe amplification (MLPA) were used to detect fetal CNVs.@*RESULTS@#The 23-year-old woman had moderate ID, sideway walking, and unstable holding. Ultrasonography at 18+3 weeks' gestation had revealed no fetal abnormality. No pathogenic CNV was detected in the woman by CNV-Seq, while WES revealed that she has harbored a heterozygous c.1675C>T (p.Arg559*) variant of the DLG4 gene, which was verified by Sanger sequencing. Based on guidelines from the American College of Medical Genetics and Genomics, the variant was predicted to be likely pathogenic (PVS1+PM2_supporting). Sanger sequencing has confirmed that the fetus has inherited this variant, and CNV-Seq also revealed that that fetus has harbored a 0.1 Mb heterozygous deletion at Xp21.1, which has encompassed the DMD gene, and the result was verified by MLPA.@*CONCLUSION@#The heterozygous c.1675C>T variant of the DLG4 gene probably underlay the mental retardation in this woman, and her fetus was found to harbor the same variant in addition with deletion of the DMD gene, which may predispose to ID type 62.

Analysis of genome copy number variations in fetuses with isolated ventricular septal defect and a literature review / 中华医学遗传学杂志

OBJECTIVE@#To assess the value of copy number variation sequencing (CNV-seq) for revealing the genetic etiology of fetuses with isolated ventricular septal defect (VSD).@*METHODS@#From December 2017 to December 2020, 69 fetuses with isolated VSD were identified at the First Affiliated Hospital of Zhengzhou University. Meanwhile, 839 similar prenatal cases were selected from public databases including Wanfang data, Wanfang Medicine, and China National Knowledge Infrastructure (CNKI) by using keywords such as "Ventricular septal defect", "Copy number variation", and "Prenatal". A total of 908 fetuses with isolated VSD were analyzed. CNV-seq was carried out for 69 fetuses.@*RESULTS@#Among the 908 fetuses, 33 (3.63%) were found to harbor pathogenic CNVs, which included 11 chromosomal aneuploidies (1.21%) and 22 pathogenic CNVs (2.42%). The pathogenic CNVs have involved 12 genetic syndromes, with those known to involve the heart development including 5 cases of 22q11.21 deletion syndrome, 2 cases of 4q terminal deletion syndrome, and 1 case of 9q subtelomere deletion syndrome. The outcome of pregnancies for 15 fetuses with pathogenic CNVs was known, of which 12 were terminated, and 3 had spontaneous closure of the ventricular septum after birth, but 1 of them had other abnormalities.@*CONCLUSION@#Fetuses with isolated VSD have a relatively high risk for chromosomal abnormalities, for which CNV-seq should be recommended.

Application of low-depth whole genome sequencing for copy number variation analysis in children with disorders of sex development / 中华医学遗传学杂志

OBJECTIVE@#To assess the value of copy number variation sequencing (CNV-seq) for the diagnosis of children with disorders of sex development (DSD).@*METHODS@#Five children with DSD who presented at the First Affiliated Hospital of Zhengzhou University from October 2019 to October 2020 were enrolled. In addition to chromosomal karyotyping, whole exome sequencing (WES), SRY gene testing, and CNV-seq were also carried out.@*RESULTS@#Child 1 and 2 had a social gender of female, whilst their karyotypes were both 46,XY. No pathogenic variant was identified by WES. The results of CNV-seq were 46,XY,+Y (1.4) and 46,XY,-Y (0.75), respectively. The remaining three children have all carried an abnormal chromosome Y. Based on the results of CNV-seq, their karyotypes were respectively verified as 45,X[60]/46,X,del(Y)(q11.221)[40], 45,X,16qh+[76]/46,X,del(Y)(q11.222),16qh+[24], and 45,X[75]/46,XY[25].@*CONCLUSION@#CNV-seq may be used to verify the CNVs on the Y chromosome among children with DSD and identify the abnormal chromosome in those with 45,X/46,XY. Above results have provided a basis for the clinical diagnosis and treatment of such children.

Analysis of a child with autosomal dominant mental retardation type 40 due to variant of CHAMP1 gene / 中华医学遗传学杂志

OBJECTIVE@#To explore the clinical and genetic features of a child with autosomal dominant mental retardation type 40 (MRD40) due to variant of the CHAMP1 gene.@*METHODS@#Clinical characteristics of the child were analyzed. Genetic testing was carried out by low-depth high-throughput and whole genome copy number variant sequencing (CNV-seq) and whole exome sequencing (WES). A literature review was also carried out for the clinical phenotype and genetic characteristics of patients with MRD40 due to CHAMP1 gene variants.@*RESULTS@#The child, a 11-month-old girl, has presented with intellectual and motor developmental delay. CNV-seq revealed no definite pathogenic variants. WES has detected the presence of a heterozygous c.1908C>G (p.Y636*) variant in the CHAMP1 gene, which was carried by neither parent and predicted to be pathogenic. Literature review has identified 33 additional children from 12 previous reports. All children had presented with developmental delay and mental retardation, and most had dystonia (94.1%), delayed speech and/or walking (85.2%, 82.4%) and ocular abnormalities (79.4%). In total 26 variants of the CHAMP1 gene were detected, with all nonsense variants being of loss-of-function type, located in exon 3, and de novo in origin.@*CONCLUSION@#The heterozygous c.1908C>G (p.Y636*) variant of the CHAMP1 gene probably underlay the WRD40 in this child. Genetic testing should be considered for children featuring global developmental delay, mental retardation, hypertonia and facial dysmorphism.

Clinical and genetic analysis of three children with KBG syndrome due to novel variants of ANKRD11 gene / 中华医学遗传学杂志

OBJECTIVE@#To explore the clinical and genetic characteristics of three children with KBG syndrome.@*METHODS@#Clinical data of the three children from two families who have presented at the First Affiliated Hospital of Zhengzhou University between October 2019 and September 2020 and their family members were collected. Trio-whole exome sequencing (trio-WES) and Sanger sequencing were carried out.@*RESULTS@#All children had feeding difficulties, congenital heart defects and facial dysmorphism. The sib- pair from family 1 was found to harbor a novel de novo heterozygous c.6270delT (p.Q2091Rfs*84) variant of the ANKRD11 gene, whilst the child from family 2 was found to harbor a novel heterozygous c.6858delC (p.D2286Efs*51) variant of the ANKRD11 gene, which was inherited from his mother who had a mild clinical phenotype.@*CONCLUSION@#The heterozygous frameshift variants of the ANKRD11 gene probably underlay the disease in the three children. Above findings have enriched the spectrum of the ANKRD11 gene variants.

Analysis of a twin pregnancy with false negative result for 22q11.2 deletion syndrome by expanded non-invasive prenatal testing / 中华医学遗传学杂志

OBJECTIVE@#To explore the cause for a twin pregnancy with false negative result for 22q11.2 deletion syndrome by expanded non-invasive prenatal testing (NIPT-plus).@*METHODS@#A pregnant woman with twin pregnancy through in-vitro fertilization and negative result of NIPT-plus was selected as the study subject. Amniocentesis was conducted after ultrasonic finding of fetal abnormalities. In addition to conventional G-banded karyotyping, copy number variation sequencing (CNV-Seq) was used to detect chromosomal microdeletion and microduplication. Clinical data of the woman were analyzed to explore the reasons underlying the false negative result.@*RESULTS@#NIPT-plus has yielded a negative result with 11.77 Mb unique reads and 3.05% fetal fraction. Both fetuses had a normal karyotype (46,XY and 46,XX). CNV-seq indicated that one of the fetuses was normal, whilst the other was diagnosed with a 2.58 Mb deletion in the 22q11.2 region.@*CONCLUSION@#The false negative result may be attributed to the combined influence of low fetal fraction, high BMI, twin pregnancy through IVF and a relatively small deletion fragment. Ultrasonography exam following a low-risk result of NIPT-plus should not be neglected.

Genetic analysis of a rare case with Disorder of sex development due to structural rearrangement of Y chromosome / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a rare case with Disorder of sex development.@*METHODS@#Clinical data of the patient was collected. Chromosomal karyotyping, SRY gene testing, whole exome sequencing (WES), low-coverage massively parallel copy number variation sequencing (CNV-seq), fluorescence in situ hybridization (FISH), and whole genome sequencing (WGS) were carried out.@*RESULTS@#The patient, a 14-year-old female, had manifested short stature and dysplasia of second sex characteristics. She was found to have a 46,XY karyotype and positive for the SRY gene. No pathogenic variant was found by WES, except a duplication at Yp11.32q12. The result of CNV-seq was 47,XYY. FISH has confirmed mosaicism for a dicentric Y chromosome. A 23.66 Mb duplication on Yp11.32q11.223 and a 5.16 Mb deletion on Yq11.223q11.23 were found by WGS. The breakpoint was mapped at chrY: 23656267. The patient's karyotype was ultimately determined as 46,X,psu idic(Y)(q11.223)/46,X,del(Y)(q11.223).@*CONCLUSION@#The combination of multiple methods has facilitated clarification of the genetic etiology in this patient, which has provided a reference for the clinical diagnosis and treatment.

Prenatal diagnosis of a case with Schuurs-Hoeijmakers syndrome / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a fetus with multiple malformations.@*METHODS@#Clinical data of the fetus was collected, Amniotic fluid sample of the fetus was subjected to conventional G-banded karyotyping, low-depth whole genome copy number variants detection and whole exome sequencing (WES). Candidate variant was verified by Sanger sequencing of the fetus and its parents.@*RESULTS@#Prenatal ultrasound scan at 21+5 gestational weeks had revealed increased nuchal thickness (9.0 mm), enhanced echos of bilateral renal parenchyma, seroperitoneum, left pleural effusion and right displacement of the heart. The mother had a previous history of terminated pregnancy for multiple fetal anomalies. No abnormality was found by conventional karyotyping and CNV analysis, though WES revealed that the fetus has harbored a de novo heterozygous c.607C>T (p.Arg203Trp) variant of the ACS1 gene (NM_018026.3), and the result was validated by Sanger sequencing.@*CONCLUSION@#Through WES and prenatal ultrasonography, the fetus was diagnosed with Schuurs-Hoeijmakers syndrome due to the heterozygous c.607C>T (p.Arg203Trp) variant of the PACS1 gene (NM_018026.3). For fetuses with multiple malformations, WES can help to reveal the genetic etiology when CNV result is negative.

Genetic testing and prenatal diagnosis for a Chinese pedigree affected with Waardenburg syndrome type 4C due to heterozygous deletion of SOX10 gene / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a Chinese pedigree featuring congenital profound syndromic deafness and chronic constipation, and provide prenatal diagnosis for a high-risk fetus.@*METHODS@#Whole-exome sequencing was carried out to analyze the sequences of genes associated with hereditary deafness, and multiplex ligation-dependent probe amplification (MLPA) was used to verify the candidate variant in the proband's parents and the fetus.@*RESULTS@#The proband was found to have harbored a heterozygous deletion of SOX10, a pathogenic gene associated with Waardenburg syndrome type 4C (WS4C). The same deletion was found in her mother (with profound syndromic deafness and chronic constipation) and the fetus, but not in her father with normal hearing. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG) and Association for Molecular Pathology (AMP), the SOX10 gene deletion was predicted to be a pathogenic variant (PVS1+PM2_Supporting+PP1+PP4).@*CONCLUSION@#The pedigree was diagnosed with WS4C, which has conformed to an autosomal dominant inheritance. Deletion of the entire SOX10 gene, as a loss-of-function variant, probably underlay its pathogenesis. Above finding has facilitated genetic counseling and prenatal diagnosis for this family.

Genetic testing and prenatal diagnosis for two Chinese pedigrees affected with Alport syndrome due to variants of COL4A5 gene / 中华医学遗传学杂志

OBJECTIVE@#To analysis variants of COL4A5 gene in two Chinese pedigrees affected with Alport syndrome (AS) and provide prenatal diagnosis for them.@*METHODS@#Two unrelated ethnic Han Chinese pedigrees who had visited the First Affiliated Hospital of Zhengzhou University respectively in September 2018 and January 2020 were selected as the study subjects. Clinical data were collected, and genomic DNA was extracted from peripheral venous blood and amniotic fluid samples for genetic testing. Following next generation sequencing, candidate variants of the COL4A5 gene were verified by Sanger sequencing and bioinformatic analysis. The gender of the fetuses was determined by the presence of sex-determining region on Y (SRY).@*RESULTS@#Genetic testing revealed that the proband and a fetus from pedigree 1 had both harbored a c.2723G>A (p.Gly908Glu) variant in exon 32 of the COL4A5 gene, whilst the proband and a fetus from pedigree 2 had both harbored a c.3817G>A (p.Gly1273Asp) variant in exon 44 of the COL4A5 gene. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), both variants were classified as likely pathogenic (PP2+PM2_Supporting). Following exclusion of maternal contamination, PCR amplification of the SRY region indicated that both fetuses were males.@*CONCLUSION@#The c.2723G>A (p.Gly908Glu) and c.3817G>A (p.Gly1273Asp) variants of the COL4A5 gene probably underlay the AS in the two pedigrees. Detection of the SRY region can reliably identify the fetal sex, which is conducive to the prenatal diagnosis. Above results have also enriched the mutational spectrum of the COL4A5 gene and provided a reference for correlating the genotype and phenotype of the AS.

Analysis of a Chinese pedigree affected with Meckel syndrome due to variants of TMEM67 gene / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic etiology for a Chinese pedigree affected with Meckel syndrome.@*METHODS@#A pedigree with a history of three consecutive adverse pregnancies which presented at the First Affiliated Hospital of Zhengzhou University on August 31, 2017 was selected as the study subject. Clinical data of the pedigree were collected. High-throughput sequencing was carried out to screen for variants of ciliopathy-related genes in the third fetus following induced abortion, and candidate variant was verified by Sanger sequencing.@*RESULTS@#The first pregnancy of the couple had ended as spontaneous abortion, whilst the fetus of the second pregnancy was suspected for having ciliopathy, though no genetic testing was carried out following elected abortion. The fetus of the third pregnancy was suspected for having ciliopathy, and high-throughput sequencing and Sanger sequencing had shown that the fetus had harbored compound heterozygous variants of the TMEM67 gene, including c.978+1G>A from the father and c.1288G>C (p.D430H) from the mother. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the c.978+1G>A was classified as a pathogenic variant (PVS1+PM2_Supporting+PP5), whilst the newly discovered c.1288G>C (p.D430H) was classified as a likely pathogenic variant (PM2_Supporting+PM3+PM5+PP3).@*CONCLUSION@#The c.978+1G>A and c.1288G>C (p.D430H) compound heterozygous variants of the TMEM67 gene probably underlay the three consecutive adverse pregnancies suspected for ciliopathy in this pedigree. The discovery of c.1288G>C (p.D430H) has also expanded the mutational spectrum of the TMEM67 gene.

Genetic diagnosis of Branchio-Oto syndrome pedigree due to a de novo heterozygous deletion of EYA1 gene / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a Chinese pedigree affected with Branchio-Oto syndrome (BOS).@*METHODS@#A pedigree with BOS which had presented at the Genetics and Prenatal Diagnosis Center of the First Affiliated Hospital of Zhengzhou University in May 2021 was selected as the study subject. Clinical data of the pedigree was collected. Peripheral blood samples of the proband and her parents were collected. Whole exome sequencing (WES) was carried out for the proband. Multiplex ligation-dependent probe amplification (MLPA) was used to verify the result of WES, short tandem repeat (STR) analysis was used to verify the relationship between the proband and her parents, and the pathogenicity of the candidate variant was analyzed.@*RESULTS@#The proband, a 6-year-old girl, had manifested severe congenital deafness, along with inner ear malformation and bilateral branchial fistulae. WES revealed that she has harbored a heterozygous deletion of 2 466 kb at chromosome 8q13.3, which encompassed the EYA1 gene. MLPA confirmed that all of the 18 exons of the EYA1 gene were lost, and neither of her parents has carried the same deletion variant. STR analysis supported that both of her parents are biological parents. Based on the guidelines from the American College of Medical Genetics and Genomics, the deletion was classified as pathogenic (PVS1+PS2+PM2_Supporting+PP4).@*CONCLUSION@#The heterozygous deletion of EYA1 gene probably underlay the pathogenicity of BOS in the proband, which has provided a basis for the clinical diagnosis.

Clinical characteristics and genetic analysis of a Chinese pedigree affected with Alström syndrome / 中华医学遗传学杂志

OBJECTIVE@#To explore the clinical characteristics and genetic etiology of a Chinese pedigree affected with Alström syndrome.@*METHODS@#A pedigree with 5 members affected with Alström syndrome who had visited the First Affiliated Hospital of Zhengzhou University in February 2021 was selected as the study subject. Clinical data of the pedigree were collected, and peripheral venous blood samples were collected for the extraction of genomic DNA. Genetic testing was carried out for the eldest daughter and third son through whole exome sequencing (WES). Candidate variant was verified by Sanger sequencing and bioinformatic analysis.@*RESULTS@#The eldest daughter (14 years old) and the third son (11 years old) both had congenital nystagmus, amblyopia, growth retardation and type 2 diabetes. WES revealed that both had harbored homozygous c.3538A>T (p.Lys1180*) variant of the ALMS1 gene. Sanger sequencing confirmed that the father, mother, and second daughter were all heterozygous carriers. Based on the Guidelines for Genetic Variation and the Technical Standards for Interpretation and Reporting of Primary Copy Number Variations, the variant was predicted as pathogenic (PVS1+PM2_Supporting+PP4).@*CONCLUSION@#The homozygous c.3538A>T (p.Lys1180*) variant of the ALSM1 gene probably underlay the Alström syndrome in this pedigree, which has provided a reference for the clinical treatment.

The value of combined CNV-Seq and chromosomal karyotyping for the detection of amniocytic mosaicisms and a literature review / 中华医学遗传学杂志

OBJECTIVE@#To assess the value of combined copy number variation sequencing (CNV-seq) and chromosomal karyotyping for the diagnosis of amniocytic mosaicisms, in addition with a literature review.@*METHODS@#Forty cases of amniocytic mosaicisms detected at the Genetic and Prenatal Diagnosis Center of the First Affiliated Hospital of Zhengzhou University from January 2018 to December 2021, in addition with 245 mosaicisms retrieved from 11 recent literature were evaluated in terms of detection rate, consistency rate, and pregnancy outcomes.@*RESULTS@#The detection rate of amniocytic mosaicisms was 0.46% (40/8 621) in our center. And its consistency rate with chromosomal karyotyping was 75.0% (30/40). After genetic counseling, 30 (75.0%) couples had opted to terminate the pregnancy, 5 (12.5%) had decided to continue with the pregnancy, 3 (7.5%) fetuses were born alive, and 2 cases (5.0%) were lost in touch. By contrast, 245 cases (0.39%) of mosaicisms were identified among 63 577 amniotic samples, with a consistency rate of 62.8% (103/164) with other techniques. Among these, 114 cases (55.1%) were terminated, 75 (36.2%) were born alive, and 18 (8.7%) were lost during the follow up.@*CONCLUSION@#Combined CNV-seq and chromosomal karyotyping has a high value for the detection of amniotic mosaicisms.

Copy number variant sequencing for chromosome analysis in 487 fetuses with increased nuchal translucency / 中华围产医学杂志

Objective:To analyze the genetic etiology of 487 fetuses with increased nuchal translucency (NT) using copy number variant sequencing (CNV-seq) and explore the relationship between increased NT and chromosomal abnormality.Methods:A retrospective study was performed on 487 fetuses with increased NT who received CNV-seq in the First Affiliated Hospital of Zhengzhou University from January 2018 to December 2020. These fetuses either had NT of ≥3.0-<3.5 mm (Group A, n=129) or ≥3.5 mm (Group B, n=358), the distribution and incidence of chromosomal abnormalities in the two sets of fetuses were analyzed using Chi square test or Fisher's exact test. Results:Fetuses with abnormal chromosomes accounted for 25.9%(126/487) of cases, including 107 with chromosome aneuploidy (22.0%) and 19 with pathogenic or likely pathogenic copy number variation (CNV, 3.9%). The detection rate of fetal aneuploidy in Group B was higher than that in Group A [14.0% (18/129) vs 24.9% (89/358), χ2=6.58, P=0.010]. However, no significant difference was observed regarding the detection rate of pathogenic or likely pathogenic CNV between the two groups ( χ2=0.30, P=0.584). Conclusions:The risk of fetal chromosome aneuploidy increased with NT thickness, but not with pathogenic or likely pathogenic CNV, which needed further verification due to the small sample size. CNV-seq is an option to detect the conventional detection methods for the genetic etiology of NT thickening fetuses.

DYNC2H1 gene mutation analysis and prenatal diagnosis in two pedigrees affected with short rib-polydactyly syndrome type Ⅲ / 中华围产医学杂志

Objective:To investigate the molecular genetic etiology of two fetuses with short rib-polydactyly syndrome type Ⅲ (SRPS Ⅲ).Methods:Next-generation sequencing (NGS) was used to detect 226 known genes related to inherited skeletal dysplasia in two fetuses with SRPS Ⅲ diagnosed in the First Affiliated Hospital of Zhengzhou University in August 2015 and June 2020. Suspect pathological variants were verified in the pedigree members using Sanger sequencing. The prenatal genetic diagnosis of the high-risk fetus in pedigree one was conducted to identify the confirmed pathogenic variation.Results:The homozygous mutation of DYNC2H1 gene c.5881A>G(p.Lys1961Glu) was identified in the proband in pedigree one, and the parents were the carriers. The proband in pedigree two carried compound heterozygous mutations in the DYNC2H1 gene with c.10606C>T(p.Arg3536*) inherited from the father and c.8954T>G(p.Val2985Gly) from the mother. Autosomal recessive inheritance was confirmed in both pedigrees. Mutations of c.5881A>G(p.Lys1961Glu) and c.8954T>G(p.Val2985Gly) in the DYNC2H1 gene were likely pathogenic variants and had not been reported before. The prenatal diagnosis did not identify the DYNC2H1 gene c.5881A>G(p.Lys1961Glu) mutation in the fetus (Ⅱ-7) in pedigree one, which was confirmed by the umbilical cord blood sample after birth. Conclusion:DYNC2H1 gene mutation underlies the fetal skeletal dysplasia in the two pedigrees.

Gene mutation analysis of 12 families with congenital cataract / 中华实验眼科杂志

Objective:To analyze the clinical manifestations of congenital cataract in 12 families and gene variants causing the disease.Methods:The method of pedigree investigation was adopted.Clinical data of 27 patients from 12 Chinese Han families with congenital cataract were collected, and genomic DNA was extracted from peripheral blood samples of patients and family members.Candidate variants were screened by next generation sequencing and were verified by Sanger sequencing.Population frequency of the variants were obtained through the Genome Arrgregation Database (gnomAD).Pathogenicity of variants was analyzed through the Human Gene Mutation Database (HGMD), Database of Single Nucleotide Polymorphism (dbSNP) and PubMed, and the mutation effect was interpreted by protein prediction softwares including SIFT, PolyPhen_2 and MutationTaster.The conservation analysis of amino acid sequences of variants was performed by GERP+ + software.Diagnosis was confirmed by clinical ophthalmic phenotype, medical history and mutation analysis.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of the First Affiliated Hospital of Zhengzhou University (No.KS-2018-KY-36).Written informed consent was obtained from all subjects and their guardians.Results:Pathogenic genetic variants were found in all the 12 families, 9 of which had known pathogenic variants including MIP c.97C>T, GJA8 c.593G>A, CRYBA4 c.277T>C, CRYBB2 c.563G>A and c.436G>C, CRYGC c.470G>A, CRYGD c.70C>A, PAX2 c.70dupG as well as OCRL E5-E16dup, and 3 novel potential pathogenic variants including CRYGD c.422delG, ELP4 c.886C>A and CRYBB2 c.434G>C. CRYGD c.422delG could lead to the early termination of translation of protein products, which was pathogenic.The nucleotide and amino acid sites of ELP4 c.886C>A and CRYBB2 c.434G>C were highly conserved among species, and were predicted as harmful.The 12 families were consistent with co-segregation. Conclusions:CRYGD c.422delG, ELP4 c.886C>A and CRYBB2 c.434G>C may be novel pathogenic variants of congenital cataract.