Analysis of a child with X-linked intellectual disability type 100 due to variant of KIF4A gene and a literature review

The use of fetal exome sequencing in prenatal diagnosis: a points to consider document of the American College of Medical Genetics and Genomics (ACMG)

ACMG SF v3.0 list for reporting of secondary findings in clinical exome and genome sequencing: a policy statement of the American College of Medical Genetics and Genomics (ACMG)

Updated recommendations for CFTR carrier screening: A position statement of the American College of Medical Genetics and Genomics (ACMG)

DNA-based screening and population health: a points to consider statement for programs and sponsoring organizations from the American College of Medical Genetics and Genomics (ACMG)

The use of ACMG secondary findings recommendations for general population screening: a policy statement of the American College of Medical Genetics and Genomics (ACMG)

To explore the clinical and genetic characteristics of a child with Arrhythmogenic right ventricular cardiomyopathy (ARVC). A 6-year-old boy with ARVC who had visited Fujian Provincial Children's Hospital on August 23, 2022 was selected as the study subject. Relevant clinical data were collected, and peripheral venous blood samples were collected from the child and his parents for genetic testing through whole exome sequencing (WES). Sanger sequencing was carried out for family verification, and pathogenicity analysis was conducted for the candidate variants. The child had exhibited clinical symptoms including systemic edema, generalized heart enlargement, universal reduction of interventricular septum and ventricular wall movement, reduced left ventricular diastolic and systolic function, and reduced right ventricular systolic function. WES revealed that the child has harbored compound heterozygous variants of the PKP2 gene, namely c.119_122del (p.Leu40ArgfsTer71) and c.1978G>A (p.Gly660Arg), which were verified by Sanger sequencing to be respectively inherited from his father and mother. The c.119_122del variant has not been recorded in the 1000 Genomes, gnomAD and ExAC databases, and was predicted to lead to truncation of the PKP2 protein by SWISS-MODEL and PyMOL online software and classified as likely pathogenic based on the guidelines jointly developed by the American College of Medical Genetics and Genomics (ACMG) and ClinGen. The c.1978G>A variant has also not been recorded in the 1000 Genomes, gnomAD and ExAC databases, and was predicted to be deleterious by online software including REVEL, SIFT, CADD, Mutation Taster, and PolyPhen-2. The amino acid encoded by the variant site was highly conserved among various species by analysis using T-coffee and ESPript v3.0 online servers. The variant may affect the protein function by SWISS-MODEL and PyMOL online server analysis, and was classified as likely pathogenic based on the guidelines jointly developed by the ACMG and ClinGen. The compound heterozygous variants of c.119_122del (p.Leu40ArgfsTer71) and c.1978G>A (p.Gly660Arg) of the PKP2 gene probably underlay the ARVC in this child. Above finding has broadened the spectrum of PKP2 gene variants and provided a reference for the diagnosis and genetic counseling.

To explore the genetic etiology for a child presenting with motor retardation, language delay, intellectual disability, and dysmorphic features. A child presented at Linyi People's Hospital in June 2022 was selected as the study subject. Clinical data of the child was collected. Peripheral blood samples were obtained from the child and her parents. Following extraction of genomic DNA, whole-exome sequencing (WES) was carried out. Candidate variant was validated by Sanger sequencing. Amniotic fluid samples were obtained from the mother's subsequent pregnancies for prenatal diagnosis. This study has been reviewed and approved by the Medical Ethics Committee of Linyi People's Hospital (Ethics No.: 2019-134). The proband was a 2-year-old girl showing developmental delays in motor, language, and intellectual domains, strabismus, hypertelorism, hearing impairment, obesity, and brachymesophalangy of the fifth finger. Magnetic resonance imaging revealed abnormalities of the white matter. Chromosomal microarray analysis (CMA) identified a 15q26.3 duplication (chr15:101562020_102060896 × 3) inherited from her mother. WES has uncovered a heterozygous c.1931A>G (p.Tyr644Cys) variant in the FBXO11 gene. Sanger sequencing confirmed the variant to be de novo in origin. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was classified as likely pathogenic. Prenatal diagnosis revealed that the fetuses from the mother's second and third pregnancies did not harbor the same variant. The c.1931A>G (p.Tyr644Cys) variant of the FBXO11 gene probably underlay the abnormal phenotype in the child. Based on its genotype and phenotype, the proband was diagnosed with Intellectual developmental disorder with dysmorphic facies and behavioral abnormalities.

To explore the clinical phenotype and genetic etiology of a child with early-onset severe obesity. A child who presented at the Department of Endocrinology, Hangzhou Children's Hospital on August 5, 2020 was selected as the study subject. Clinical data of the child were reviewed. Genomic DNA was extracted from peripheral blood samples of the child and her parents. Whole exome sequencing (WES) was carried out on the child. Candidate variants were verified by Sanger sequencing and bioinformatic analysis. This child was a 2-year-and-9-month girl featuring severe obesity with hyperpigmentation on the neck and armpit skin. WES revealed that she has harbored compound heterozygous variants of the MC4R gene, namely c.831T>A (p.Cys277*) and c.184A>G (p.Asn62Asp). Sanger sequencing confirmed that they were respectively inherited from her father and mother. The c.831T>A (p.Cys277*) has been recorded by the ClinVar database. Its carrier frequency among normal East Asians was 0.000 4 according to the 1000 Genomes, ExAC, and gnomAD databases. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), it was rated as pathogenic. The c.184A>G (p.Asn62Asp) has not been recorded in the ClinVar, 1000 Genomes, ExAC and gnomAD databases. Prediction using IFT and PolyPhen-2 online software suggested it to be deleterious. Based on the guidelines from the ACMG, it was determined as likely pathogenic. The c.831T>A (p.Cys277*) and c.184A>G (p.Asn62Asp) compound heterozygous variants of the MC4R gene probably underlay the early-onset severe obesity in this child. Above finding has further expanded the spectrum of MC4R gene variants and provided a reference for the diagnosis and genetic counseling for this family.

Does the law require reinterpretation and return of revised genomic results?

One is the loneliest number: genotypic matchmaking using the electronic health record

To explore the clinical characteristics and genetic etiology of a patient with mental retardation and ejaculatory dysfunction. A patient with mental retardation and ejaculatory dysfunction who was admitted to the First Affiliated Hospital of Air Force Military Medical University on November 18, 2021 was selected as the study subject. Clinical data of the patient were collected. Peripheral venous blood samples were collected from the patient and his parents. Whole exome sequencing (WES) was carried out for the patient, and the candidate variant was verified by Sanger sequencing and bioinformatic analysis. The patient, a 26-year-old male, had manifested atypical mental retardation and ejaculatory dysfunction. WES revealed that he has harbored a heterozygous variant of the ARID1B gene, namely c.5776C>T (p.Arg1926X). Sanger sequencing verified that neither of his parents has carried the same variant. The variant has been recorded in the 1000 Genomes, ExAC, gnomAD and ClinVar databases. A search of the dbSNP database suggested that the variant has a population frequency of 0.000 4%. The variant was predicted as deleterious by online software including Mutation Taster, CADD, and MutPred. Analysis with Cluster Omega online software suggested that the amino acid encoded by the variant site was highly conserved among various species. Analysis with PyMOL software suggested that the variant may affect the function of the encoded protein. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG) and ClinGen, the variant was predicted to be pathogenic. The c.5776C>T (p.Arg1926X) variant of the ARID1B gene probably underlay the mental retardation and ejaculatory dysfunction in this patient. Above finding has broadened the spectrum of the ARID1B gene variants and provided reference for the diagnosis and treatment of the patient.

DNA-based screening and personal health: a points to consider statement for individuals and health-care providers from the American College of Medical Genetics and Genomics (ACMG)

To explore the genetic etiology of a child with Spastic paraplegia and psychomotor retardation with or without seizures (SPPRS). A child who was admitted to the Children's Hospital Affiliated to Nanjing Medical University in April 2022 for motor developmental delay, intellectual disability, and hypertonia was selected as the study subject. Relevant clinical data were retrospectively analyzed. Whole exome sequencing (WES) was carried out for the child and his parents. Candidate variants were searched in the Single Nucleotide Polymorphism Database (dbSNP) and Online Mendelian Inheritance in Man (OMIM) database. Pathogenicity of the variants was assessed based on guidelines from the American College of Medical Genetics and Genomics (ACMG). Using key words such as "HACE1 gene" "Spastic paraplegia and psychomotor retardation with or without seizures" and "SPPRS", previous reports on SPPRS patients due to HACE1 gene variants were retrieved from the CNKI, Wanfang Data Knowledge Service Platform, CQVIP, and PubMed databases, with the time set from January 1, 2000 to April 7, 2024. A mutation map for the HACE1 protein in the patients was created. This study was approved by the Ethics Committee of the Children's Hospital Affiliated to Nanjing Medical University (Ethics No. 202404008-1). The clinical manifestations of the child had included motor developmental delay, intellectual disability and hypertonia. Magnetic resonance imaging revealed hypoplasia of posterior corpus callosum and splenium, with slight enlargement of lateral ventricles. WES revealed that the child has harbored compound heterozygous variants of the HACE1 gene, namely c.535(exon7)_c.538(exon7)delACAG (p.T179fs*5) and c.1678+2(IVS15)T>C, which were respectively inherited from his parents. Based on the guidelines from the ACMG, the variants were respectively rated as likely pathogenic (PVS1 + PM2_Supporting) and pathogenic (PVS1 + PM2_Supporting + PM3). Literature search has identified 8 papers, which reported 23 SPPRS cases due to HACE1 gene variants. All patients exhibited psychomotor developmental delay, among whom 18 HACE1 gene variants were identified. The c.535(exon7)_c.538(exon7)delACAG (p.T179fs*5) and c.1678+2(IVS15)T>C compound heterozygous variants of the HACE1 gene probably underlay the pathogenesis of SPPRS in this child. Above discovery has enriched the mutational and phenotypic spectrum of the HACE1 gene and provided a reference for clinical diagnosis and genetic counseling.

To investigate the clinical characteristics and genetic etiology of a child with Cortical dysplasia, complex, with other brain malformations 4 (CDCBM4) and epilepsy due to a TUBG1 gene variant. A child diagnosed with CDCBM4 and epilepsy at the Children's Medical Center of the Affiliated Hospital of Guangdong Medical University in May 2024 was selected as the study subject. Clinical data were retrospectively analyzed. Peripheral venous blood samples were collected from the child and her parents for genomic DNA extraction. Trio-based whole-exome sequencing (WES) was performed, and candidate variants were validated by Sanger sequencing. According to the Standards and Guidelines for the Interpretation of Sequence Variants established by the American College of Medical Genetics and Genomics (ACMG), candidate variants were classified for pathogenicity. This study was approved by the Medical Ethics Committee of the Affiliated Hospital of Guangdong Medical University (Ethics No.: PJ2021-097). The child, a 4-month-old female infant, had no special facial features, normal limb muscle strength, and increased muscle tone of infantile onset, with generalized tonic-clonic seizures as the main manifestation. During seizures, she exhibited head retroflexion, tightly closed eyes, and tonic convulsions of the limbs, occurring approximately 2-3 times per day. Electroencephalogram suggested bilateral anterior predominant medium-to-high amplitude 7-8 Hz mixed rhythm discharges. Head MRI revealed ventricular system dilatation and pachygyria. Trio-WES results indicated that the child has harbored a TUBG1 gene variant of c.776C>T (p.Ser259Leu). Sanger sequencing verification showed that neither of her parents had carried the same variant, confirming it as de novo in origin. According to the ACMG guidelines, the variant was rated as pathogenic (PS2+PS3+PM2_Supporting+PP3). Combining the child's clinical phenotype, the child was diagnosed as CDCBM4 with epilepsy. Children with CDCBM4 and epilepsy due to TUBG1 gene variants may show pachygyria or agyria and commonly present with intellectual and motor developmental delays and seizure disorders of variable severity. The heterozygous TUBG1 c.776C>T (p.Ser259Leu) variant is likely the genetic etiology underlying this disorder. The results of this study has expanded the mutational spectrum of the TUBG1 gene associated with CDCBM4 and epilepsy.

Focused Revision: ACMG practice resource: Genetic evaluation of short stature