See http://www.disgenet.org/rdf

 disease(?D:disgenet_disease) is nondet

 gene(?G:disgenet_gene) is nondet

 association(?A:disgenet_annotation) is nondet

 gene_disease_association(?A:disgenet_annotation) is nondet

 gene_disease_association(?A:disgenet_annotation, ?G:disgenet_gene, ?D:disgenet_disease) is nondet

 gene_disease_association(?A:disgenet_annotation, ?G:disgenet_gene, ?D:disgenet_disease, ?P) is nondet

gene G is associated with disease D via evidence A

 disease_pair_by_shared_gene(?D1:disgenet_disease, ?D2:disgenet_disease, ?G:disgenet_gene) is nondet

both D1 and D2 are associated with the same gene G

Undocumented predicates

The following predicates are exported, but not or incorrectly documented.

 refers_to(Arg1, Arg2)

 has_evidence(Arg1, Arg2)

 gene_disease_association(Arg1, Arg2, Arg3)

 gene_disease_association(Arg1, Arg2, Arg3, Arg4)