INTRODUÇÃO: O diabetes mellitus (DM) é considerado um problema importante de saúde pública; possui prevalência elevada e nos últimos anos observa-se aumento progressivo na sua incidência. OBJETIVO: verificar possíveis variações na concentração de hemoglobina (Hb) glicada (HbA1c) na presença de Hbs S e C e avaliar o impacto da redução da HbA1c na avaliação clínica e no monitoramento do paciente diabético. MATERIAL E MÉTODOS: Foram incluídos no estudo, 150 indivíduos diabéticos oriundos da cidade de Salvador, Bahia, de ambos os gêneros, com idade média de 56 anos. Foram determinadas a glicemia de jejum e a HbA1c por metodologia de oxidase-peroxidase e cromatografia líquida de alta eficiência (CLAE), respectivamente. RESULTADOS: Foram observadas variações na concentração da HbA1c em função da presença de variantes de Hb, como 7,85%, AA; 7,30%, AS e 7,15%, AC. DISCUSSÃO E CONCLUSÃO: A metodologia analítica a ser utilizada para determinação de HbA1c deve ser escolhida com base nas características gerais da população atendida e nas comorbidades associadas, pois a presença de Hbs S e C ocasiona reduções significativas de glicação. Essa redução pode levar a interpretações clínicas inadequadas relativas ao controle glicêmico dos pacientes.

INTRODUCTION: Diabetes mellitus (DM) is considered an important public health problem. It is highly prevalent and its incidence has progressively increased in recent years. OBJECTIVE: To verify possible variations of glycated hemoglobin (HbA1c) concentration in the presence of Hb S and Hb C and to evaluate the impact of HbA1c reduction on clinical evaluation and monitoring of diabetic patients. MATERIAL AND METHODS: This study comprised 150 diabetic individuals from Salvador city, Bahia, from both genders and average age of 56 years old. Fast blood glucose and HbA1c were determined by oxidase-peroxidase and high-performance liquid chromatography (HPLC) methods, respectively. RESULTS: There were variations in the concentration of HbA1c in the presence of hemoglobin variants such as AA (7.85%), AS (7.30%), and AC (7.15%). DISCUSSION AND CONCLUSION: The analytical method used to determine HbA1c needs to be chosen according to the general population characteristics and associated comorbidities, since the presence of hemoglobin S and C causes significant reductions in hemoglobin glycation, which may lead to clinical misinterpretation of patients' glycemic control.

The null genotype for glutathione S-transferase (GST, EC 2.5.1.18) gene polymorphisms is considered a risk factor for leukemia in different populations. In this work we investigated the GSTT1 and GSTM1 polymorphisms using multiplex PCR in 53 patients with chronic myeloid leukemia (CML), 23 with acute promyelocytic leukemia (APL) and 304 apparently healthy controls. In this association study we found that the GSTT1null genotype was more frequent in our group of APL patients than in the control group [OR = 2.75 (95% CI = 1.10-6.88)], providing evidence that a deletion in the GSTT1 gene could be a risk factor for this type of leukemia.

Methylenetetrahydrofolate reductase (MTHFR: EC 1.5.1.20) polymorphisms are associated to acute lymphoid leukemia in different populations. We used the polymerase chain reaction and the restriction fragment length polymorphism method (PCR-RFLP) to investigate MTHFR C677T and A1298C polymorphism frequencies in 67 patients with chronic myeloid leukemia (CML), 27 with acute myeloid leukemia FAB subtype M3 (AML-M3) and 100 apparently healthy controls. The MTHFR mutant allele frequencies were as follows: CML = 17.2% for C677T, 21.6% for A1298C; AML-M3 = 22.2% for C677T, 24.1% for A1298C; and controls = 20.5% for C677T, 21% for A1298C. Taken together, our results provide evidence that MTHFR polymorphisms have no influence on the development of CML or AML-M3.