Allelic Heterogeneity

Allelic heterogeneity is the phenomenon in which different mutations at the same locus causes a similar phenotype. For example, β-thalassemia may be caused by several different mutations in the β-globin gene.

Allelic heterogeneity should not be confused with locus heterogeneity in which a mutation at a different gene causes a similar phenotype.

Nor should it be confused with phenotypic heterogeneity in which a mutation within the same gene causes a different phenotype.