Gene Databases: NCBI Gene, Ensembl, and OMIM Explained

The bioinformatics revolution has produced powerful public databases that catalog human genes, their functions, associated diseases, and genetic variants. Understanding these databases and how to navigate them is essential for researchers, clinicians, and curious individuals interested in the genetics of health and disease.

NCBI Gene and RefSeq

NCBI Gene (National Center for Biotechnology Information) is the primary U.S. government gene database, providing comprehensive information for each gene including genomic location, molecular structure (exons, introns, regulatory regions), reference sequences (RefSeq), protein products, expression data, associated diseases, literature references, and links to related databases.

The RefSeq database provides curated, non-redundant reference sequences for DNA, RNA, and proteins. Standardized accession numbers (e.g., NM_ for mRNA, NP_ for protein) are used in publications and clinical genetics reports to precisely specify which sequence and variant is being discussed.

Ensembl: Integrated Genome Browser

Ensembl is a genome browser developed by EMBL-EBI and the Wellcome Sanger Institute, providing integrated views of the genome incorporating gene annotations, comparative genomics, regulatory features, and genetic variation. Ensembl gene IDs (ENSG...) are widely used in research publications. The Variant Effect Predictor (VEP) tool within Ensembl annotates variants with their predicted functional consequences.

OMIM: Online Mendelian Inheritance in Man

OMIM (Online Mendelian Inheritance in Man) is the authoritative catalog of human genetic disorders and the genes that cause them. Each OMIM entry includes clinical descriptions, molecular genetics information, inheritance patterns, and an extensive bibliography. OMIM numbers (MIM numbers) are standard references in clinical genetics reports.

ClinVar and gnomAD

ClinVar aggregates variant-disease significance assertions from clinical laboratories, providing information about the clinical significance of specific variants. GnomAD (Genome Aggregation Database) provides allele frequency information for variants across diverse human populations, essential for distinguishing rare pathogenic variants from common benign polymorphisms. Together, these databases power modern clinical variant interpretation.

For more on genomics resources and research tools, visit our resources section.