OMIM is actively involved in various international efforts to classify and reorganize disease nosologies and ontologies. In 2017, OMIM participated in the reclassification of the limb-girdle muscular dystrophies (11). OMIM is an active participant in the ClinGen (12) Lumping and Splitting Work Group. (Classically, ‘lumping and splitting’ has been used to describe genetic heterogeneity of a phenotype. ClinGen, however, uses it to describe phenotypic diversity at a locus.) In addition, OMIM is working with the international Gene Curation Collaboration (GenCC), a group of curated resources working to harmonize terminology to define the nature of different gene-disease relationships.
