hypermorph /hī″pərmôrf′/ [Gk, hyper + morphe, form] , 1. a person whose arms and legs are disproportionately long in relation to the trunk, and whose sitting height is disproportionately short compared to the standing height. 2. a mutant allele that has an increased effect on the expression of a trait. Compare amorph, antimorph, hypomorph.
