OBJECTIVE: To analyze the clinical phenotype and genetic variant of a child with Snijders Blok-Campeau syndrome (SBCS). METHODS: A child who was diagnosed with SBCS in June 2017 at Henan Children's Hospital was selected as the study subject. Clinical data of the child was collected. Peripheral blood samples of the child and his parents were collected and the extraction of genomic DNA, which was subjected to trio-whole exome sequencing (trio-WES) and genome copy number variation (CNV) analysis. Candidate variant was verified by Sanger sequencing of his pedigree members. RESULTS: The main clinical manifestations of the child have included language delay, intellectual impairment and motor development delay, which were accompanied with facial dysmorphisms (broad forehead, inverted triangular face, sparse eyebrows, widely spaced eyes, narrow palpebral fissures, broad nose bridge, midface hypoplasia, thin upper lip, pointed jaw, low-set ears and posteriorly rotated ears). Trio-WES and Sanger sequencing revealed that the child has harbored a heterozygous splicing variant of the CHD3 gene, namely c.4073-2A>G, for which both of his parents were of wild-type. No pathogenic variant was identified by CNV testing. CONCLUSION The c.4073-2A>G splicing variant of the CHD3 gene probably underlay the SBCS in this patient.
DNA Copy Number Variations ; Heterozygote ; Pedigree ; Phenotype ; RNA Splicing ; Mutation

OBJECTIVE: To analyze the sequence of the F12 gene and molecular mechanism for 20 patients with coagulation factor Ⅻ (FⅫ) deficiency. METHODS: The patients were selected from the outpatient department of the Second Hospital of Shanxi Medical University from July 2020 to January 2022. The activity of coagulation factor Ⅷ (FⅧ:C), factor Ⅸ (FⅨ:C), factor Ⅺ (FⅪ:C) and factor Ⅻ (FⅫ:C) were determined by using a one-stage clotting assay. All exons and 5' and 3' UTR of the F12 gene were analyzed by Sanger sequencing to detect the potential variants. Bioinformatic software was used to predict the pathogenicity of the variants, conservation of amino acids, and protein models. RESULTS: The FⅫ:C of the 20 patients has ranged from 0.07% to 20.10%, which was far below the reference values, whilst the other coagulation indexes were all normal. Sanger sequencing has identified genetic variants in 10 patients, including 4 with missense variants [c.820C>T (p.Arg274Cys), c.1561G>A (p.Glu521Lys), c.181T>C (p.Cys61Arg) and c.566.G>C (p.Cys189Ser)], 4 deletional variants c.303_304delCA(p.His101GlnfsX36), 1 insertional variant c.1093_1094insC (p.Lys365GlnfsX69) and 1 nonsense variant c.1763C>A (p.Ser588*). The remaining 10 patients only harbored the 46C/T variant. The heterozygous c.820C>T(p.Arg274Cys) missense variant in patient 1 and the homozygous c.1763C>A (p.Ser588*) nonsense variant in patient 2 were not included in the ClinVar and the Human Gene Mutation Database. Bioinformatic analysis predicted that both variants were pathogenic, and the corresponding amino acids are highly conserved. The protein prediction models suggested that the c.820C>T (p.Arg274Cys) variant may affect the stability of the secondary structure of FⅫ protein by disrupting the original hydrogen bonding force and truncating the side chain, leading to changes in the vital domain. c.1763C>A (p.Ser588*) may produce a truncated C-terminus which may alter the spatial conformation of the protein domain and affect the serine protease cleavage site, resulting in extremely reduced FⅫ:C. CONCLUSION Among individuals with low low FⅫ:C detected by one-stage clotting assay, 50% have harbored variants of the F12 gene, among which the c.820C>T and c.1763C>A were novel variants underlying the reduced coagulating factor FⅫ.
Humans ; Factor XII/genetics* ; Pedigree ; Mutation ; Mutation, Missense ; Heterozygote ; Factor XII Deficiency/genetics*

OBJECTIVE: To analyze variant of LDLR gene in a patient with familial hypercholesterolemia (FH) in order to provide a basis for the clinical diagnosis and genetic counseling. METHODS: A patient who had visited the Reproductive Medicine Center of the First Affiliated Hospital of Anhui Medical University in June 2020 was selected as the study subject. Clinical data of the patient was collected. Whole exome sequencing (WES) was applied to the patient. Candidate variant was verified by Sanger sequencing. Conservation of the variant site was analyzed by searching the UCSC database. RESULTS: The total cholesterol level of the patient was increased, especially low density lipoprotein cholesterol. A heterozygous c.2344A>T (p.Lys782*) variant was detected in the LDLR gene. Sanger sequencing confirmed that the variant was inherited from the father. CONCLUSION The heterozygous c.2344A>T (p.Lys782*) variant of the LDLR gene probably underlay the FH in this patient. Above finding has provided a basis for genetic counseling and prenatal diagnosis for this family.
Humans ; Cholesterol, LDL/genetics* ; Heterozygote ; Hyperlipoproteinemia Type II/genetics* ; Mutation ; Pedigree ; Phenotype ; Receptors, LDL/genetics*

OBJECTIVE: To explore the clinical characteristics and genetic etiology of a child with multiple pterygium syndrome (MPS). METHODS: A child with MPS who was treated at the Orthopedics Department of Guangzhou Women and Children's Medical Center Affiliated to Guangzhou Medical University on August 19, 2020 was selected as the study subject. Clinical data of the child was collected. Peripheral blood samples of the child and her parents were also collected. Whole exome sequencing (WES) was carried out for the child. Candidate variant was validated by Sanger sequencing of her parents and bioinformatic analysis. RESULTS: The child, an 11-year-old female, had a complain of "scoliosis found 8 years before and aggravated with unequal shoulder height for 1 year". WES results revealed that she has carried a homozygous c.55+1G>C splice variant of the CHRNG gene, for which both of her parents were heterozygous carriers. By bioinformatic analysis, the c.55+1G>C variant has not been recorded by the CNKI, Wanfang data knowledge service platform and HGMG databases. Analysis with Multain online software suggested that the amino acid encoded by this site is highly conserved among various species. As predicted with the CRYP-SKIP online software, the probability of activation and skipping of the potential splice site in exon 1 caused by this variant is 0.30 and 0.70, respectively. The child was diagnosed with MPS. CONCLUSION The CHRNG gene c.55+1G>C variant probably underlay the MPS in this patient.
Humans ; Child ; Female ; Abnormalities, Multiple/genetics* ; Malignant Hyperthermia/genetics* ; Skin Abnormalities/genetics* ; Heterozygote ; Mutation ; Receptors, Nicotinic/genetics*

OBJECTIVE: To explore the genetic etiology for a Chinese pedigree affected with Lesch-Nyhan syndrome. METHODS: Members of the pedigree who had visited the Genetic Counseling Clinic of Linyi People's Hospital on February 10, 2022 were selected as the study subjects. Clinical data and family history of the proband were collected, and trio-whole exome sequencing (trio-WES) was carried out for the proband and his parents. Candidate variants were verified by Sanger sequencing. RESULTS: Trio-WES revealed that both the proband and his cousin brother had harbored a hemizygous c.385-1G>C variant in intron 4 of the HPRT1 gene, which was unreported previously. A heterozygous c.385-1G>C variant of the HPRT1 gene was also found in the proband's mother, grandmother, two aunts, and a female cousin, whilst all phenotypically normal males in his pedigree were found to have a wild type for the locus, which has conformed to an X-linked recessive inheritance. CONCLUSION The heterozygous c.385-1G>C variant of the HPRT1 gene probably underlay the Lesch-Nyhan syndrome in this pedigree.
Male ; Humans ; Female ; Lesch-Nyhan Syndrome/genetics* ; Pedigree ; East Asian People ; Heterozygote ; Introns ; Mutation

OBJECTIVE: To analyze the clinical features and genotype of a child with Schmid type metaphyseal chondrodysplasia. METHODS: Clinical data of the child and her parents was collected. The child was subjected to high-throughput sequencing, and candidate variant was verified by Sanger sequencing of her family members. RESULTS: Whole exome sequencing revealed that the child has harbored a heterozygous c.1772G>A (p.C591Y) variant of the COL10A1 gene, which was not found in either of her parents. The variant was not found in the HGMD and ClinVar databases, and was rated as likely pathogenic based on the guidelines from the American College of Medical Genetics and Genomics (ACMG). CONCLUSION The heterozygous c.1772G>A (p.C591Y) variant of the COL10A1 gene probably underlay the Schmid type metaphyseal chondrodysplasia in this child. Genetic testing has facilitated the diagnosis and provided a basis for genetic counselling and prenatal diagnosis for this family. Above finding has also enriched the mutational spectrum of the COL10A1 gene.
Humans ; Child ; Female ; Mutation ; Osteochondrodysplasias/diagnosis* ; Heterozygote ; Molecular Biology

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.
Humans ; Intellectual Disability/genetics* ; Genetic Testing ; Phenotype ; Exome Sequencing ; Heterozygote ; Mutation ; Chromosomal Proteins, Non-Histone/genetics* ; Phosphoproteins/genetics*

OBJECTIVE: To explore the clinical characteristics and genetic etiology of a child with Schaaf-Yang syndrome (SYS). METHODS: Peripheral blood samples of the child and his parents were collected and subjected to whole exome sequencing. Sanger sequencing was used for family constellation verification, and bioinformatic analysis was performed for the candidate variant. RESULTS: The child, a 1-year-and-9-month-old boy, had clinical manifestations of retarded growth, small penis, and unusual facies. Genetic testing revealed that the child has harbored a novel heterozygous variant of c.3078dupG (p.Leu1027Valfs*28) of the MAGEL2 gene. Sanger sequencing showed that neither parent of the child carried the same variant. The c.3078dupG(p.Leu1027Valfs*28) variant of the MAGEL2 gene has not been included in the databases of ESP, 1000 Genomes and ExAC. According to the Standards and Guidelines for the Interpretation of Sequence Variants of the American College of Medical Genetics and Genomics (ACMG), the variant was judged to be pathogenic. CONCLUSION The c.3078dupG (p.Leu1027Valfs*28) variant of the MAGEL2 gene probably underlay the SYS in this child, which has further expanded the spectrum of the MAGEL2 gene variants.
Child ; Humans ; Infant ; Male ; Exome Sequencing ; Genetic Testing ; Heterozygote ; Mutation ; Proteins/genetics* ; Developmental Disabilities/genetics*

OBJECTIVE: To explore the genetic basis for a child with mental retardation. METHODS: Whole exome sequencing was carried out for the child. Candidate variant was screened based on his clinical features and verified by Sanger sequencing. RESULTS: The child was found to harbor a c.995_1002delAGACAAAA(p.Asp332AlafsTer84) frameshift variant in the SYNGAP1 gene. Bioinformatic analysis suggested it to be pathogenic. The same variant was not detected in either parent. CONCLUSION The c.995_1002delAGACAAAA(p.Asp332AlafsTer84) frameshift variant of the SYNGAP1 gene probably underlay the mental retardation in this child. Above finding has expanded the spectrum of SYNGAP1 gene variants and provided a basis for the diagnosis and treatment for this child.
Child ; Humans ; Intellectual Disability/genetics* ; Frameshift Mutation ; High-Throughput Nucleotide Sequencing ; Computational Biology ; Heterozygote ; Mutation ; ras GTPase-Activating Proteins/genetics*

OBJECTIVE: To explore the genetic basis for a child with Aspartylglucosaminuria (AGU). METHODS: Clinical data of the patient was analyzed. The child was subjected to trio-whole exome sequencing (WES) and copy number variation sequencing (CNV-seq), and candidate variant was verified by Sanger sequencing. RESULTS: The child was found to harbor homozygous c.319C>T (p.Arg107*) nonsense variant of the AGA gene, for which both of his parents were heterozygous carriers. No abnormality was found by CNV-seq analysis. The c.319C>T (p.Arg107*) variant was not found in population database, HGMD and other databases. Based on guidelines of the American College of Medical Genetics and Genomics, the variant was predicted to be pathogenic (PVS1+PM2+PP3). CONCLUSION The c.319C>T variant of the AGA gene probably underlay the autosomal recessive AGU in this child. Above finding has enabled genetic counseling and prenatal diagnosis for his parents.
Female ; Pregnancy ; Humans ; Child ; Aspartylglucosaminuria ; DNA Copy Number Variations ; Genetic Counseling ; Genomics ; Heterozygote ; Mutation