OBJECTIVE: Recombination events are common and serve as the primary driving force of diverse human adenovirus (HAdV), particularly in children with acute respiratory tract infections (ARIs). Therefore, continual monitoring of these events is essential for effective viral surveillance and control. METHODS: Respiratory specimens were collected from children with ARIs between January 2022 and December 2023. The penton base, hexon, and fiber genes were amplified from HAdV-positive specimens and sequenced to determine the virus type. In cases with inconsistent typing results, genes were cloned into the pGEM-T vector to detect recombination events. Metagenomic next-generation sequencing (mNGS) was performed to characterize the recombinant HAdV genomes. RESULTS: Among 6,771 specimens, 277 (4.09%, 277/6,771) were positvie for HAdV, of which 157 (56.68%, 157/277) were successfully typed, with HAdV-B3 being the dominant type (91.08%, 143/157), and 14 (5.05%, 14/277) exhibited inconsistent typing results, six of which belonged to species B. The penton base genes of these six specimens were classified as HAdV-B7, whereas their hexon and fiber genes were classified as HAdV-B3, resulting in a recombinant genotype designated P7H3F3, which closely resembled HAdV-B114. Additionally, a partial gene encoding L1 52/55 kD was identified, which originated from HAdV-B16. CONCLUSION A novel recombinant, P7H3F3, was identified, containing sequences derived from HAdV-B3 and HAdV-B7, which is similar to HAdV-B114, along with additional sequences from HAdV-B16.
Humans ; Adenoviruses, Human/isolation & purification* ; Respiratory Tract Infections/epidemiology* ; Child, Preschool ; Child ; Recombination, Genetic ; Male ; Beijing/epidemiology* ; Infant ; Female ; Phylogeny ; Adenovirus Infections, Human/epidemiology* ; Acute Disease ; Genome, Viral

OBJECTIVE: To re-analyze a likely pathogenic variant in the Xq28 region identified by copy number variation sequencing (CNV-seq) through whole genome sequencing (WGS). METHODS: A fetus found to harbor a duplication in the Xq28 region by CNV-seq at Shengjing Hospital Affiliated to China Medical University in May 2023 was selected as the study subject. WGS was carried out for the fetus and its parents. Bioinformatic software was used to analyze the chromosomal structure and CNVs. Quantitative PCR (qPCR) was applied to determine the expression level of the MECP2 gene. This study has been approved by the Ethics Committee of Shengjing Hospital (Ethic No. 2013PS33K). RESULTS: A duplication (ChrX:153302641_153503563) and four breakpoints were identified on the X chromosome of the fetus' father. Bioinformatic analysis revealed that the duplicated region has involved exons 1 to 3 and part of the 5'-UTR of the MECP2 gene, which was inserted into the Xp11 region. Additionally, an inversion was detected in the Xp11 region adjacent to the duplicated segment. RT-PCR results showed normal level of MECP2 mRNA expression. The Xq28 duplication has not encompassed the entire MECP2 gene, nor disrupted its structure or altered its expression. CONCLUSION WGS has enabled more precise diagnosis of chromosomal structural variants and provided guidance for accurate genetic counseling for the affected families.
Humans ; Female ; Chromosomes, Human, X/genetics* ; DNA Copy Number Variations/genetics* ; Whole Genome Sequencing/methods* ; Methyl-CpG-Binding Protein 2/genetics* ; Pregnancy ; Male ; Adult

The exploration of pathogenic single nucleotide polymorphisms in the genome plays a pivotal role in the study of human disease-associated genetic mutations. However, there remains a lack of suitable high-throughput screening platforms to investigate the impact of point mutations on genomic structure and function. CRISPR/Cas9-mediated base editors has enabled large-scale annotation of the human genome and phenotypic characterization of monogenic disorders. Base editors, a precise gene-editing technique capable of achieving targeted base substitutions, can be employed to induce mutations at specific functional sites, thereby observing their effects on gene expression, protein function, and cellular phenotypes. Furthermore, integrating base editors with high-throughput screening technologies allows for large-scale evaluation of multiple candidate sites, accelerating the identification of functional loci and providing a powerful tool for disease research and therapeutic target discovery. This article aims to introduce the working principles of various base editors, including cytosine base editors, adenine base editors, and prime editors, and summarize recent advances in high-throughput screening of functional genomic sites using base-editing techniques.
Humans ; Gene Editing/methods* ; CRISPR-Cas Systems/genetics* ; Genome, Human ; Polymorphism, Single Nucleotide

The International System for Human Cytogenomic Nomenclature (ISCN) is a standardized international nomenclature system established by the International Standing Committee on Human Cytogenomic Nomenclature (ISCN SC). It is designed for describing chromosomal or genomic abnormalities detected by commonly used genetic and genomic techniques including but not limited to karyotyping, fluorescence in situ hybridization, microarray, genome mapping, various region-specific assays, and high-throughput sequencing. With a history spanning over six decades, the ISCN was revised by the ISCN SC in 2024 and officially published in September 2024. This article provides a summary for the updates introduced in the 2024 edition of the International System for Human Cytogenomic Nomenclature.
Humans ; Terminology as Topic ; Genomics ; Genome, Human/genetics*

Optical genome mapping (OGM) is an emerging technology for the detection of genetic diseases based on physical mapping, which can detect numerical chromosomal abnormalities, copy number variation (CNV) and structural variation (SV) on a genome-wide scale. In recent years, a number of studies have proved that OGM, as a new generation of cytogenomic technique, has higher resolution and stronger ability to discover genomic variants compared with conventional genetic techniques. This article has systematically reviewed the principles, characteristics, advantages and limitations of OGM technology, and its applications in the diagnosis of genetic disorders.
Humans ; DNA Copy Number Variations ; Chromosome Mapping/methods* ; Genetic Diseases, Inborn/diagnosis* ; Genome, Human

Mosaic chromosomal alteration (mCA) is referred to as large-scale somatic mutations on chromosomes, which results in diverse karyotypes in body. The mCA is regarded as one of the phenotypes of aging. Studies have revealed its associations with many chronic diseases such as hematopoietic cancers and cardiovascular diseases, but its genetic basis (e.g. genetic susceptibility variants) is still under-investigated. This paper reviews GWAS studies for mCA on autosomal chromosomes and sex chromosomes [mosaic loss of the Y chromosome (mLOY) and mosaic loss of the X chromosome (mLOX)] based on large population, respectively. Most of the genetic susceptibility loci found in studies for autosomal mCA were associated with copy-neutral loss of heterozygosity. The study of sex chromosome mCA focused on mosaic loss mutations. The number of genetic susceptibility loci for mLOY was high (up to 156), but it was relatively less for mLOX.
Humans ; Male ; Genome-Wide Association Study/methods* ; Mosaicism ; Genetic Predisposition to Disease ; Chromosomes, Human, Y ; Mutation

ACGS Best Practice Guidelines for Variant Classification in Rare Disease 2020, a supplementary practical guidelines, is based on the Standards and Guidelines for the Interpretation of Sequence Variations issued by the American Society for Medical Genetics and Genomics (ACMG) and the Association of Molecular Pathology (AMP) in 2015 by the British Medical Genetics Society under the Clinical Genomics Society (ACGS), and has integrated the detailed rules of standards developed by the ClinGen Sequence Variant Interpretation (SVI) Working Group by 2020. The further development of the ACMG/AMP guidelines is currently undertaken by the ClinGen SVI working group in the United States, which focuses on the classification of high penetrance and protein coding variants. ClinGen has established many expert panels on variants for specific diseases which required various evidence thresholds and is currently developing disease/gene specific guidelines. The British Medical Genetics Society has collected and integrated information on the guidelines for sequence variation classification and their extended rules, forming its own "2020 ACGS Best Practice Guidelines for Rare Disease Variation Classification" and is regularly updating it. The author has translated and summarized it for the reference of Chinese Medical Genetics Practitioners.
Humans ; Genetic Testing ; Genetic Variation ; Genome, Human ; Rare Diseases/genetics* ; China

Copy number variants (CNVs) are common causes of human genetic diseases. CNVs detection has become a routine component of genetic testing, especially for pediatric neurodevelopmental disorders, multiple congenital abnormalities, prenatal evaluation of fetuses with structural anomalies detected by ultrasound. Although the technologies for CNVs detection are continuously improving, the interpretation is still challenging, with significant discordance across different laboratories. In 2020, the American College of Medical Genetics and Genomics (ACMG) and the Clinical Genome Resource (ClinGen) developed a guideline for the interpreting and reporting of constitutional copy number variants, which introduced a quantitative, evidence-based scoring framework. Here, we detailed the key points of interpreting the copy number gain based on the guideline, used six examples of different categories to illuminate the scoring process and principles. We encourage a professional understanding and application of this guideline for the detected copy number gains in China in order to further improve the clinical evaluation accuracy and consistency across different laboratories.
Child ; DNA Copy Number Variations ; Female ; Genetic Testing ; Genetics, Medical ; Genome, Human/genetics* ; Genomics ; Humans ; Pregnancy ; United States

OBJECTIVE: Through a retrospective large sample analysis of copy number variants in single center, we explored the technical standards for the interpretation and reporting of constitutional copy-number variants (CNVs) jointly proposed by the American College of Medical Genetics and Genomics (ACMG) and the Clinical Genome Resource (ClinGen) in 2019, analyzing its impact on CNVs ratings and the improvement in the consistency of the classification of CNVs in clinical laboratories. METHODS: 236 CNVs that assessed as pathogenic, uncertain significant (including likely pathogenic, uncertain and likely benign) by the 2011 ACMG guidelines between August 2018 and December 2019 in our center were re-analyzed. Four working group members of the center reclassified and evaluated 235 CNVs according to 2019 ACMG guidelines. RESULTS: The consistency of clinical significance classification of CNVs was 91% and the α test coefficient was 0.98 among four working group members. Compared with the 2011 and 2019 ACMG technical standards for the CNVs classification, evaluation of pathogenicity and uncertain significant is basically consistent. 90% (45/50) of likely pathogenic and likely benign CNVs were Re-evaluated as variants of uncertain significance, and the difference is significant. CONCLUSION The new version ACMG/ClinGen guidelines for the evaluation of CNVs developed semi-quantitative point-based scoring system and help to improve the consistency in clinical classifications. It can also make the interpretation of CNVs more standardized and transparent.
DNA Copy Number Variations ; Genetic Testing ; Genetic Variation ; Genome, Human ; Humans ; Mutation ; Retrospective Studies

OBJECTIVE: To analyze the genome-wide DNA methylation differences in umbilical cord blood nucleated red blood cells (NRBCs) between term and preterm infants by using the methylation gene chip technology, and to screen the genes of differential methylation and biological signaling pathways which may be related to the expression of γ-globin gene (HBG). METHODS: Umbilical cord bloods of eight term infants and eight preterm infants were collected, and NRBCs of each sample was isolated, then genome DNA was extracted and bisulfite conversion was performed. The DNA methylation sites were detected by using the Illumina 850K BeadChip. Differential DNA methylation sites were screened, and the function of genes with differential methylation was analyzed by using GO and KEGG enrichment analysis. RESULTS: Compared with the preterm group, 4749 differential DNA methylation sites of term group were screened out, including 4359 hypomethylation sites and 390 hypermethylation sites. GO and KEGG analysis indicated that the function of genes with differential methylation mainly involved in the hemopoietic system, growth and development process, Wnt and Notch signal pathways. CONCLUSION The differentical methylation sites at genome-wide level in umbilicar cord blood NRBC of term and preterm infants have been obtained, and the signal pathway and genes which possibily related with swiching the expression of γ-globin gene to β-globin gene have been screened-out. This study provide the new targets for studing the mechamism regulating expression of HBG gene.
DNA ; DNA Methylation ; Epigenesis, Genetic ; Fetal Blood ; Genome, Human ; Humans ; Infant, Newborn ; Infant, Premature