Phenotypic analysis of Hbab2(th) heterozygous mice shows similar hematological alterations to those in humans with α-thalassemia minor (Popp and Enlow 1977; Whitney et al. 1981), which is a result of deletions or other mutations in two of the four alpha-globin alleles (either in cis or trans) (Tesio and Bauer 2023). The gene discussed is HBA2; the disease is thalassemia.