Objective:To analyze the genetic test results and ultrasonographic markers of 41 fetuses with short femurs and their relationship.Methods:This study retrospectively analyzed 41 fetuses who were diagnosed with short femurs by ultrasound during 19-37 gestational weeks and underwent prenatal genetic examination at the First Affiliated Hospital of Zhengzhou University from January 2018 to June 2019. According to the results of genetic examination, these cases were divided into three groups after excluding three cases of variants of unknown significance: genetically normal group, chromosome variation (including chromosomal aneuploidy and pathogenic or likely pathogenic copy number variations) group, and gene mutation (including pathogenic or likely pathogenic gene mutations) group. According to the head circumference (HC), abdominal circumference (AC) and femur length (FL), Z FL, FL/HC, FL/AC, ΔZ H-F and ΔZ H+A-2F for each fetus were calculated. One-way ANOVA and LSD- t test were used for statistical analysis. Results:(1) Among the 41 fetuses with short femurs, there were 28 in the genetically normal group, five in the chromosome variation group, three with chromosome variations of unknown significance and five in the gene mutation group. (2) In the genetically normal, chromosome variation and gene mutation groups, Z FL values were -2.78±0.77, -4.36±0.69 and -4.69±0.70; FL/HC ratios were 0.178±0.011, 0.170±0.010 and 0.131±0.022; FL/AC ratios were 0.197±0.013, 0.186±0.011 and 0.151±0.017; ΔZ H-F values were 2.49±1.09, 3.53±1.28 and 8.17±1.30; ΔZ H+A-2F values were 4.44±2.00, 6.78±2.20 and 14.28±1.26, respectively. The differences in Z FL values between the genetically normal group and the chromosome variation group as well as the gene mutation group were statistically significant (both P<0.05); so were the differences in FL/HC, FL/AC and ΔZ H-F values between the gene mutation group and the genetically normal group as well as the chromosome variation group (all P<0.05) and in any pairwise comparison of ΔZ H+A-2F among the three groups (all P<0.05). Conclusions:The genetic etiology of fetal short femurs is mainly related to chromosomal variations (including chromosomal aneuploidy and pathogenic or likely pathogenic copy number variations) and gene mutation. In fetuses with chromosome variation and gene mutation, the degree of the femoral development delay relative to the development of HC and AC is worse than that in the normal genetic results group.

OBJECTIVE: To analyze the prenatal diagnosis, parental verification and pregnancy outcome of 6 fetuses with 22q11.2 microdeletion syndrome. METHODS: Copy number variation sequencing (CNV-seq)and chromosomal microarray analysis (CMA) were carried out for the fetuses. RESULTS: The fetuses were found to harbor 2.54-3.2 Mb microdeletions of the 22q11.2 region, among which one was maternally inherited and one was paternally inherited. Two parents opted to continue with the pregnancy, and 4 chose induced labor. One fetus was found to have tetralogy of Fallot, while two carrier parents and one fetus appeared to have normal phenotype. CONCLUSION 22q11.2 microdeletions identified upon prenatal diagnosis should be treated carefully, with ultrasonic scan and parental verification taken into account.
DNA Copy Number Variations ; Female ; Fetus ; Humans ; Microarray Analysis ; Pregnancy ; Pregnancy Outcome ; Prenatal Diagnosis ; Ultrasonography, Prenatal

OBJECTIVE: To identify the pathogenic variants of 4 patients with hemolytic anemia of unknown cause. METHODS: Peripheral blood samples of the patients and their family members were collected to extract DNA. The coding region and splice region in all exons of gene of erythrocyte related diseases were analyzed by using target sequence capture and high-throughput sequencing technology. Suspected pathogenic variants were verified by PCR combined Sanger sequencing technology. RESULTS: Each of the probands was detected two compound heterozygous variants, and CDA II was diagnosed. Six variants were detected in the 4 probands, four variants were reported and the other two were first reported. CONCLUSION By high-throughput sequencing, gene variant of CDA II be analyzed fast and accurately. It is an effective supplement to convenional diagnostic methods. Furthermore, the novel variant sites have enriched the variant database of the SEC23B gene.
Anemia, Dyserythropoietic, Congenital/genetics* ; Exons/genetics* ; High-Throughput Nucleotide Sequencing ; Humans ; Mutation ; Vesicular Transport Proteins/genetics*

Objective: To evaluate the application value and significance of low-depth whole-genome sequencing for copy number variations (CNV-Seq) in the genetic diagnosis and prenatal diagnosis of X-linked ichthyosis (XLI) due to STS gene deletion. Methods: Clinical data were collected from 3 616 subjects who received CNV-Seq, and single-gene test results were collected from 7 patients or pedigrees with ichthyosis in The First Affiliated Hospital of Zhengzhou University in 2018. The 3 616 samples included 2 891 prenatal samples from pregnant women (most were amniotic fluid samples, some fetal villus samples, very few umbilical blood samples) and 725 peripheral blood samples from other subjects. Genomic DNA was extracted from amniocytes or peripheral blood, and then subjected to CNV-Seq. Quantitative PCR (qPCR) and single nucleotide polymorphism (SNP) -comparative genomic hybridization (CGH) array were performed to verify the detected CNVs. Pathogenicity of the CNVs was analyzed according to the database of genomic variants (DGV) , database of genomic variation and phenotype in humans using ensembl resources (DECIPHER) , clinical genome resource (ClinGen) and online Mendelian inheritance in man (OMIM) . Results: Of the 3 616 subjects receiving CNV-Seq, Xp22.31 deletion was identified in prenatal samples from 6 pregnant women, including 5 male and 1 female fetuses. The deleted fragment of Xp22.31 covered the XLI region containing the major gene STS. The parental CNV-Seq showed that the Xp22.31 deletion was spontaneous mutation in 2 of the 6 fetuses, and inherited from the parents in the other 4 fetuses. qPCR confirmed that the female fetus was a carrier of a complete heterozygous deletion of the STS gene, and there was a complete deletion of the STS gene in the other 5 male fetuses. SNP-CGH array also confirmed that the female fetus was heterozygous Xp22.31 deletion carrier, which was consistent with the CNV-Seq results. Ichthyosis gene panel sequencing in the 7 patients with ichthyosis showed 1 with harlequin ichthyosis, 2 with ichthyosis vulgaris, 3 with XLI, and no causative mutation in 1. CNV-Seq confirmed that Xp22.31 deletion existed in the above 2 patients with XLI due to STS gene deletion. Moreover, Xp22.31 duplication was found in 16 out of 3 616 subjects receiving CNV-Seq, but they were all individuals or fetuses with normal phenotype. Conclusions CNV-Seq is a stable and reliable method for screening whole-genome CNVs, and can be applied to genetic diagnosis and prenatal diagnosis of XLI due to STS gene deletion. The deletion of Xp22.31 fragment containing the STS gene can cause XLI, and the duplication of the same region is highly likely to be the polymorphic variation.

OBJECTIVE: To analyze the clinical symptom and parental origin of patients with MECP2 duplication syndrome in order to provide a basis for genetic counseling and prenatal diagnosis. METHODS: Clinical symptoms of four patients who were diagnosed with MECP2 duplication syndrome by copy number variation sequencing (CNV-Seq) were reviewed. The maternal origin of the duplications were verified. RESULTS: All patients were males, and CNV-Seq revealed that they have all harbored a duplication in the Xq28 region spanning 0.32 ~ 0.86 Mb, which were derived from asymptomatic mothers. The clinical symptoms of three patients with three copies included delayed speech, intellectual disability, and muscular hypotonia, while the patient with four copies had died at 6 months after birth, with clinical symptoms including recurrent infections, seizures, and spasticity. CONCLUSION The four cases of MECP2 duplication syndrome have shown complete penetrance and have all derived from asymptomatic mothers. As a stable and reliable method, CNV-Seq can accurately detect the MECP2 duplication syndrome.
Chromosomes, Human, X ; DNA Copy Number Variations ; Gene Duplication ; Humans ; Male ; Mental Retardation, X-Linked ; Methyl-CpG-Binding Protein 2/genetics* ; Phenotype

OBJECTIVE: To detect genomic copy number variations (CNVs) among 145 children with unexplained mental retardation/developmental delay (MR/DD) by using low-depth whole-genome copy number variation sequencing (CNV-seq). METHODS: Peripheral blood samples were collected from the patients and subjected to DNA extraction and CNV-seq. The results were analyzed by a combination of bioinformatic tools. RESULTS: Forty-nine patients were found to carry a total of 67 CNVs with an average size of 5.27 Mb. Among these, 22 patients were assessed to carry MR/DD-related CNVs involving 21 syndromes. This gave a diagnostic rate of 15.17%(22/145) for CNVs associated with unexplained MR/DD. The corresponding regions of the 22 MR/DD-related CNVs in the human genome covered 174 MR/DD-related pathogenic genes, which have mapped to 18 sections on 10 chromosomes. CONCLUSION Genomic CNVs-related microdeletions/duplications account for a significant proportion of unexplained MR/DD, for which CNV-seq can provide an accurate diagnosis.

OBJECTIVE: To assess the value of chromosomal microarray analysis (CMA) for the analysis of 824 samples from miscarriage or stillbirth. METHODS: Copy number variations (CNVs) in the abortic chorionic villi or stillbirth tissues were detected by CMA. RESULTS: All specimens were successfully analyzed, among which 381 (46.2%) were diagnosed with chromosomal abnormalities, which included 312 (81.9%) numerical abnormalities, 66 (17.3%) structural abnormalities and 3 (0.8%) uniparental disomies. Among numerical chromosomal abnormalities, aneuploidies was most common (92.0%), with trisomy 16 and 45,X accounting for 41 (13.1%) and 63 (20.2%) of the cases, respectively. Among the 66 structural chromosomal aberrations, there were 26 (39.4%) CNVs duplications, 20 (30.3%) CNVs deletions, and 20 (30.3%) CNVs duplication and deletions. 33 CNVs were predicted as have a high chance to lead to a disease. CONCLUSION CMA is a reliable, robust, and high-resolution method for the analysis of miscarriage or stillbirth samples. Numerical aberrations, in particular chromosomal aneuploides, are the main cause for spontaneous abortions and stillbirths.
Abortion, Spontaneous ; genetics ; Chromosome Aberrations ; Chromosome Disorders ; diagnosis ; genetics ; DNA Copy Number Variations ; Female ; Humans ; Microarray Analysis ; Pregnancy ; Stillbirth ; genetics

OBJECTIVE: To assess the value of copy number variation sequencing (CNV-seq) and karyotyping in the prenatal diagnosis for carriers of balanced translocations. METHODS: Clinical records of 135 amniocentesis samples of balanced translocation carriers undergoing simultaneous CNV-seq and karyotyping were analyzed. Chromosomal aberrations were defined as those can definitely lead to birth defects definitely, which included chromosomal numerical abnormality, large deletion/duplication and pathogenic copy number variations (pCNVs). RESULTS: The detection rates for karyotyping and CNV-seq were 4.44% (6/135) and 5.93% (8/135) respectively, and the latter had a detection rate of 1.48(2/135) higher than the former. A total of 68 fetal chromosomal translocations were detected by karyotying analysis. CONCLUSION For couples carrying a balanced translocation, simultaneous CNV-seq and karyotyping is conducive to the detection of fetal chromosomal abnormalities and genetic counseling.
Chromosome Aberrations ; Chromosome Disorders/genetics* ; DNA Copy Number Variations ; Female ; Humans ; Karyotyping ; Pregnancy ; Prenatal Diagnosis ; Translocation, Genetic

OBJECTIVE: To explore the genetic basis for a girl with distinctive facial features, epilepsy, intellectual disability, chronic constipation and hypopigmentation of neck and upper extremities. METHODS: Whole exome sequencing was carried out for the proband. Candidate variant was verified by Sanger sequencing. RESULTS: The proband was found to harbor a heterozygous nonsense c.586G>T (p.Glu196*) variant of the ZEB2 gene, which was unreported previously. The variant was not detected in either parent. CONCLUSION The ZEB2 gene c.586G>T (p.Glu196*) variant probably underlay the Mowat-Wilson syndrome in this patient. Hypopigmentation in the neck and upper extremities may be related to Mowat-Wilson syndrome. Prenatal diagnosis was recommended for subsequent pregnancies.
Facies ; Female ; Hirschsprung Disease ; Humans ; Hypopigmentation ; Intellectual Disability/genetics* ; Microcephaly ; Pregnancy ; Zinc Finger E-box Binding Homeobox 2/genetics*

OBJECTIVE: To summarize the genetic diagnosis, low-depth copy number variation sequencing (CNV-seq) and prenatal finding in 7 fetuses with 2p16.3 deletions only involving the NRXN1 gene. METHODS: The 7 fetuses have all been found to have loss of heterozygosity at 2p16.3 by CNV-seq, which were verified by quantitative real-time PCR (qPCR). Specific regions of NRXN1 gene deletions were identified, and the CNVs were verified in their parents. Outcome of the pregnancies were followed up. RESULTS: Among 16 502 prenatal samples, 7 fetuses were found to harbor a 120 kb ~ 900 kb microdeletion in the 2p16.3 region, which yielded a prevalence of 0.424‰. The deleted region mainly involved 50 200 000-51 880 000 positions of chromosome 2 and involved only the NRXN1 gene. All of the 7 fetal CNVs were confirmed by qPCR, including 2 cases with heterozygous deletion of exons 1 to 6, 1 with heterozygous deletion of exons 1 to 19, 1 with heterozygous deletion of exons 19 to 22, and 3 with heterozygous deletion of introns 6 to 7 of the NRXN1 gene. Verification in the parents had found that one deletion was inherited from the father, 1 was from the mother, 2 cases were de novo in origin, whilst the remaining 3 had refused parental verification. After genetic counseling, one couple had elected induced abortion, 1 case has not been born yet, whilst the other 5 cases were born healthy. Follow up had identified no mental abnormalities among the children. CONCLUSION Seven fetuses with heterozygous 2p16.3 deletions only involving the NRXN1 gene were detected by CNV-seq. The specific deletion of the NRXN1 gene was verified by qPCR. Prenatal genetic counseling and fertility guidance has been provided to the particular family by combining the results of CNV testing, pedigree analysis and pregnancy outcome.
Female ; Humans ; Pregnancy ; Calcium-Binding Proteins/genetics* ; Cell Adhesion Molecules, Neuronal/genetics* ; DNA Copy Number Variations ; Nerve Tissue Proteins/genetics* ; Neural Cell Adhesion Molecules/genetics* ; Prenatal Diagnosis ; Real-Time Polymerase Chain Reaction ; Infant, Newborn