Deletion of two out of four alpha chain gene loci results in alpha thalassemia minor. The deletions may be heterozygous (two on the same chromosome, inherited from either mother or father) or homozygous (one from each of two chromosomes, inherited from both mother and father). Alpha thalassemia minor does not produce a clinical disease but may be discovered upon routine testing.
Both the heterozygous and homozygous form are common in Southeast Asians. The homozygous form of alpha thalassemia minor has been shown in African Americans as well.
