Hematological and molecular analysis of patients with G6PD deficiency revealed coexistent hereditary spherocytosis and alpha thalassemia.

BACKGROUND: Glucose-6-phosphate dehydrogenase (G6PD) deficiency, hereditary spherocytosis (HS), and alpha thalassemia (α-thal) are frequent erythrocyte pathologies with different geographic distributions worldwide. Our aim is to report hematological and molecular findings of G6PD deficient Mexican patients in coinheritance with suggestive hereditary spherocytosis (sHS) and α-thal. METHODS: We studied 78 G6PD deficiency patients. Hematological parameters, acidified glycerol lysis test, erythrocyte morphology, electrophoresis, and hemoglobin quantification were obtained. G6PD and HBA2/HBA1 variants were identified using ARMS-PCR, Gap-PCR, or Sanger sequencing. RESULTS: Nine G6PD variants were identified; A-202A/376G , A-376G/968C , and A+376G as the most frequent. G6PD Santiago de Cuba1339A and Kamiube1387T were detected in Mexicans for first time. Hematological analysis revealed additional erythrocyte pathologies in 52 patients, 32 with positive osmotic fragility test and spherocytes in blood smear (suggestive hereditary spherocytosis, sHS), 12 with microcytosis and 8 with all three defects who had the most severe phenotype, with significantly lower hematological parameters (Hb, PCV, MCV, and MCH). α-thal variants (αHph α, α-59C>T α and -α3.7 ) were observed in 65% of patients with microcytosis. CONCLUSION: Additional erythrocyte defects were observed in 69.3% of G6PD deficiency patients. We stress the importance of searching for the presence of additional erythrocyte hereditary diseases in patients with G6PD deficiency.

Effects of SPTA1 Gene Variants on the Hematological Phenotype of Mexican Patients with Hereditary Spherocytosis.

Introduction: Hereditary spherocytosis (HS) is a common hereditary hemolytic anemia characterized by chronic hemolysis, increased indirect serum bilirubin, the presence of reticulocytes and spherocytes in blood smears, and great heterogeneity at the clinical, biochemical, and molecular levels. The molecular pathology of HS includes genetic variants at five genes: ANK1, EPB42, SLC4A1, SPTA1, and SPTB. Alpha spectrin (SPTA1) deficiency is the second leading cause of HS in Mexican patients. Aim: To assess the effects of five SPTA1 variants on the hematological phenotype of Mexican patients with HS. Materials and Methods: This study included a retrospective cohort of 227 biologically unrelated patients with HS. Variants c.4339-99C>T and c.6531-12C>T in SPTA1 were identified by the amplification-refractory mutation system polymerase chain reaction (ARMS-PCR), and variants c.5572C>T, c.5992C>G, and c.6794T>C were identified by quantitive Real Time-Polymerase Chain Reaction (qRT-PCR) allelic discrimination. Risk tests were performed for each variant with respect to HS clinical severity. Results: The SPTA1 c.5992C>G variant showed association with moderately severe HS (p = 0.006, odds ratio = 5.67, confidence interval95% = 1.6-19.9); the risk increased when the variant was in compound heterozygosity with αLELY and c.6794T>C. Lower hematological levels were observed in simple αLely (c.5572C>T and c.6531-12C>T), and c.5992C>G heterozygotes (red blood cell [RBC] p = 0.028 and 0.010; hemoglobin [Hb] p = 0.030 and 0.002; packed cell volume [PCV] p = 0.034 and 0.002 respectively), and in c.5992C>G+c.6794T>C compound heterozygotes (RBC p = 0.043; Hb p = 0.033; PCV p = 0.043). Additional genetic traits were observed: 15% had HS+Gilbert syndrome and 13% HS+thalassemia. Conclusion: Although most of the studied variants are considered benign, we observed significant associations with phenotypic severity. Therefore, we recommend the inclusion of these variants in molecular screening for HS.