Prevalence of glutathione S-transferase gene deletions and their effect on sickle cell patients

BACKGROUND: Glutathione S-transferase gene deletions are known detoxification agents and cause oxidative damage. Due to the different pathophysiology of anemia in thalassemia and sickle cell disease, there are significant differences in the pathophysiology of iron overload and iron-related complications in these disorders. OBJECTIVE: The aim of this study was to estimate the frequency of the GSTM1 and GSTT1 genotypes in sickle cell disease patients and their effect on iron status. METHODS: Forty sickle cell anemia and sixty sickle ß-thalassemia patients and 100 controls were evaluated to determine the frequency of GST gene deletions. Complete blood counts were performed by an automated cell analyzer. Hemoglobin F, hemoglobin A, hemoglobin A2 and hemoglobin S were measured and diagnosis of patients was achieved by high performance liquid chromatography with DNA extraction by the phenol-chloroform method. The GST null genotype was determined using multiplex polymerase chain reaction and serum ferritin was measured using an ELISA kit. Statistical analysis was by EpiInfo and GraphPad statistics software. RESULTS: An increased frequency of the GSTT1 null genotype (p-value = 0.05) was seen in the patients. The mean serum ferritin level was higher in patients with the GST genotypes than in controls; this was statistically significant for all genotypes except GSTM1, however the higher levels of serum ferritin were due to blood transfusions in patients. CONCLUSION: GST deletions do not play a direct role in iron overload of sickle cell patients.

Genotypic influence of alpha-deletions on the phenotype of Indian sickle cell anemia patients / 대한혈액학회지

BACKGROUND: Some reports have shown that co-inheritance of alpha-thalassemia and sickle cell disease improves hematological parameters and results in a relatively mild clinical picture for patients; however, the exact molecular basis and clinical significance of the interaction between alpha-thalassemia and sickle cell disease in India has not yet been described. There is little agreement on the clinical effects of alpha-thalassemia on the phenotype of sickle cell disease. METHODS: Complete blood count and red cell indices were measured by an automated cell analyzer. Quantitative assessment of hemoglobin variants HbF, HbA, HbA2, and HbS was performed by high performance liquid chromatography (HPLC). DNA extraction was performed using the phenol-chloroform method, and molecular study for common alpha-deletions was done by gap-PCR. RESULTS: Out of 60 sickle cell anemia patients, the alpha-thalassemia genotype was found in 18 patients. Three patients had the triplicated alpha-genotype (Anti alpha-3.7 kb), and the remaining patients did not have alpha-deletions. This study indicates that patients with co-existing alpha-thalassemia and sickle cell disease had a mild phenotype, significantly improved hematological parameters, and fewer blood transfusions than the patients with sickle cell anemia without co-existing alpha-deletions. CONCLUSION: Co-existence of alpha-thalassemia and sickle cell anemia has significant effects on the phenotype of Indian sickle cell patients.