Molecular and Hematological Analysis of Alpha- and Beta-Thalassemia in a Cohort of Mexican Patients

Introduction: Alpha- and beta-thalassemia are caused by reduced or absent synthesis of hemoglobin (Hb) subunits α and/or β. HBA2, HBA1, and HBB mutations are the main cause of thalassemias. The aim of this article is to analyze molecular and hematological features of α- and β-thal in a cohort of Mexican patients. Methods: One hundred forty-one thalassemia patients were studied. Peripheral blood was collected for blood cell count, electrophoresis, Hb quantification, and molecular testing. Molecular screening was performed by Gap-PCR, ARMS-PCR, Sanger sequencing, and MLPA. Results: Fifty-four patients had α-thal, 75 β-thal, and 12 patients were complex cases, we observed 13 α- and 18 β-thal alleles in 43 genotypes, -α^3.7/αα and β^Cd39C>T/β were the most frequent. Four α-thal deletions (-^Mex4 included HBA2 and HBA1, whereas (αα)^{Mex5, Mex6 and Mex7} involved MCS-R), a hereditary persistence of fetal hemoglobin-2 like (HPFH-2 like) deletion and six alleles not previously reported in Mexicans (α^-59C>Tα, -α^4.2, α^Plasenciaα, β^-32C>T, β^InitCdA>C and β^FSCd71/72+A) were identified. Conclusion: The observed alleles denote the high heterogeneity and multiple origin admixture of Mexican population. Hematological data are consistent with genotypes, variability in simple carriers, from asymptomatic forms to mild or moderate anemia, was ascertained. We emphasize the importance to consider hematological parameters to establish adequate molecular screening strategies.