TABLE 3.

Numbers of pairs of co-occurring phenotypes for the OMIM and Orphanet databases. Significantly co-occurring pairs defined as having a hypergeometric index value $\ge 2$.

Category	OMIM	Orphanet
Total co-occurring phenotype pairs	455 379	467 899
Significant co-occurring pairs ($HyI\ge 2$)	125 720	99 193
Significant co-occurring pairs, NMD phenotypes	4 579	2 314
Significant co-occurring pairs, non-NMD phenotypes a	$655\pm 46.4$	$173\pm 16.43$

^aThis result is expressed as the average ± SD for 100 sets of 335 randomly chosen OMIM non-NMD phenotypes and 216 random Orphanet non-NMD phenotypes; the non-NMD phenotypes were selected to have a similar prevalence to the NMD phenotypes.