Interpreting genetic variants in the context of protein function and phenotype is central to elucidating disease mechanisms. The rapid accumulation ofhuman genomic data has revealed extensive inter-individual variation, enabling systematic evaluation of variant pathogenicity. Public resources such as gnomAD and OMIM, together with standardized phenotype frameworks including the Human Phenotype Ontology (HPO), support integrative analyses linking genotype to clinical presentation. In glycan-related disorders, particularly congenital disorders of glycosylation (CDG), interpretation remains challenging due to the structural complexity of glycan biosynthesis and incompletefunctional annotation of many proteins. Integrating population-scale datasets, pangenome analyses, and advanced sequencing technologies is refining pathogenicity classification and strengthening precision medicine. Continued efforts to connect variant frequency, structural and functional impact, and phenotype data will enhance our understanding of glycan-related diseases and human biological diversity.