Schematic representation of distinct disease-to-gene relationships.

<p>Different disease associations between genes using (A) the data from genetic disease databases or (B) their associated pathological phenotypes. (A) The co-associations of genes in disease/s allow the inference of gene-to-gene projection (unipartite) from the disease-to-gene projection (bipartite). In this case Gene B and Gene C are co-associated with Disease C. (B) The HPO annotations of genetic diseases allow the description of pathophenotypic space for genes and calculation of the semantic similarity (pathophenotypic similarity) between them. In this case, novel relationships emerge as occur between Gene A and Gene B or Gene A and Gene C. (C) The proposed classification in this work: monogenic disease and monotropic genes (MD-MG), monogenic disease and pleiotropic genes (MD-PG), polygenic disease and monotropic gene (PD-MG), polygenic disease and pleiotropic gene (PD-PG). It is noteworthy that genes present in the MD-PG subset can also be present in the PD-PG subset (dashed line linked to monogenic disease in grey).