Kidney dysfunction and beta S-haplotypes in patients with sickle cell disease

OBJETIVE: To investigate the association between kidney dysfunction and haplotypes in sickle cell disease. METHODS: A cohort of 84 sickle cell disease patients, treated in a public health service in Fortaleza, Brazil, was studied. Hemoglobin S haplotypes were obtained from 57 patients as they had recently received blood transfusions with 18 of them agreeing to undertake urinary concentrating ability and acidification tests. The glomerular filtration rate was estimated using the Modification of Diet in Renal Disease Study equation. Urinary concentration was evaluated utilizing the urinary and serum osmolality ratio (U/P(osm)) after 12 hours of water deprivation. Urinary acidification was evaluated by measuring the urinary pH before and after the administration of oral CaCl(2). The analysis of the haplotypes of the beta S gene cluster was carried out by polymerase chain reaction-restriction fragment length polymorphism. The analysis of variance (ANOVA) test was used for multiple comparisons of means and the Newman-Keuls test was used to identify which groups were significantly different. RESULTS: The mean age of the patients was 33 ± 13 years with 64.2% being females. The glomerular filtration rate was normal in 25 cases (30%) and a rate > 120 mL/min was seen in 52 cases (62%). Urinary concentration deficit was found in all patients who underwent the test and urinary acidification in 22%. There was no significant difference when comparing patients with the Bantu/Bantu and Benin/Benin haplotypes. On comparing patients with the Central African Republic-haplotype however, a higher number had glomerular filtration rates between 60 and 120 mL/min. CONCLUSION: There was no significant difference among sickle cell disease patients regarding the haplotypes and kidney dysfunction.