Resposta a longo prazo com sulfonilureia em um paciente com diabetes associado à mutação no gene KCNJ11

OBJECTIVE: To report the long-term (30-month) effect of the switch from insulin to sulfonylurea in a patient carrying the p.G53D (c.158G>A) mutation in KCNJ11 gene. SUBJECT AND METHOD: A 29-year-old male patient was diagnosed with diabetes in the third month of life and after identification of a heterozygous p.G53D mutation in the KCNJ11 gene, the therapy was switched from insulin to sulfonylurea. RESULTS: Long-term follow-up (30 months) showed that good metabolic control was maintained (HbA1c: 6.6%) and the glibenclamide dose could be reduced. CONCLUSION: Long-term therapy with sulfonylureas in patients with neonatal diabetes due to mutation in the KCNJ11 gene is safe and promotes sustained improvement of glycemic control.OBJETIVO: Reportar o efeito a longo prazo (30 meses) da substituição de insulina por sulfonilureia em um paciente com a mutação p.G53D (c.158G>A) no gene KCNJ11. SUJEITO E MÉTODO: Paciente do sexo masculino, atualmente com 29 anos de idade, foi diagnosticado com diabetes melito no terceiro mês de vida e, após identificação da mutação p.G53D (c.158G>A) em heterozigose no gene KCNJ11, a terapia foi substituída de insulina para sulfonilureia. RESULTADOS: Seguimento a longo prazo (30 meses) mostrou que o bom controle metabólico foi mantido (HbA1c: 6,6%) e a dose de glibenclamida pode ser reduzida. CONCLUSÃO: A terapia com sulfonilureia a longo prazo em pacientes com diabetes neonatal decorrente de mutações no gene KCNJ11 é segura e promove uma melhora persistente no controle metabólico.Universidade Federal de São Paulo (UNIFESP) Division of EndocrinologyUNIFESP, Division of EndocrinologySciEL

Specific insulin and proinsulin in normal glucose tolerant first-degree relatives of NIDDM patients

In order to identify early abnormalities in non-insulin-dependent diabetes mellitus (NIDDM) we determined insulin (using an assay that does not cross-react with proinsulin) and proinsulin concentrations. The proinsulin/insulin ratio was used as an indicator of abnormal ß-cell function. The ratio of the first 30-min increase in insulin to glucose concentrations following the oral glucose tolerance test (OGTT; I30-0/G30-0) was taken as an indicator of insulin secretion. Insulin resistance (R) was evaluated by the homeostasis model assessment (HOMA) method. True insulin and proinsulin were measured during a 75-g OGTT in 35 individuals: 20 with normal glucose tolerance (NGT) and without diabetes among their first-degree relatives (FDR) served as controls, and 15 with NGT who were FDR of patients with NIDDM. The FDR group presented higher insulin (414 pmol/l vs 195 pmol/l; P = 0.04) and proinsulin levels (19.6 pmol/l vs 12.3 pmol/l; P = 0.03) post-glucose load than the control group. When these groups were stratified according to BMI, the obese FDR (N = 8) showed higher fasting and post-glucose insulin levels than the obese NGT (N = 9) (fasting: 64.8 pmol/l vs 7.8 pmol/l; P = 0.04, and 60 min post-glucose: 480.6 pmol/l vs 192 pmol/l; P = 0.01). Also, values for HOMA (R) were higher in the obese FDR compared to obese NGT (2.53 vs 0.30; P = 0.075). These results show that FDR of NIDDM patients have true hyperinsulinemia (which is not a consequence of cross-reactivity with proinsulin) and hyperproinsulinemia and no dysfunction of a qualitative nature in ß-cells.Universidade Federal de São Paulo (UNIFESP)UNIFESPSciEL

Variants of transcription factor 7-like 2 (TCF7L2) gene and incident glucose intolerance in Japanese-Brazilians

Common variants of the transcription factor 7-like 2 (TCF7L2) gene have been found to be associated with type 2 diabetes in different ethnic groups. The Japanese-Brazilian population has one of the highest prevalence rates of diabetes. Therefore, the aim of the present study was to assess whether two single-nucleotide polymorphisms (SNPs) of TCF7L2, rs7903146 and rs12255372, could predict the development of glucose intolerance in Japanese-Brazilians. In a population-based 7-year prospective study, we genotyped 222 individuals (72 males and 150 females, aged 56.2 ± 10.5 years) with normal glucose tolerance at baseline. In the study population, we found that the minor allele frequency was 0.05 for SNP rs7903146 and 0.03 for SNP rs12255372. No significant allele or genotype association with glucose intolerance incidence was found for either SNP. Haplotypes were constructed with these two SNPs and three haplotypes were defined: CG (frequency: 0.94), TT (frequency = 0.027) and TG (frequency = 0.026). None of the haplotypes provided evidence for association with the incidence of glucose intolerance. Despite no associations between incidence of glucose intolerance and SNPs of the TCF7L2 gene in Japanese-Brazilians, we found that carriers of the CT genotype for rs7903146 had significantly lower insulin levels 2 h after a 75-g glucose load than carriers of the CC genotype. In conclusion, in Japanese-Brazilians, a population with a high prevalence of type 2 diabetes, common TCF7L2 variants did not make major contributions to the incidence of glucose tolerance abnormalities.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Disciplina de EndocrinologiaUniversidade de São Paulo Instituto do CoraçãoUNIFESP, EPM, Disciplina de EndocrinologiaSciEL

Specific insulin and proinsulin secretion in glucokinase-deficient individuals

Glucokinase (GCK) is an enzyme that regulates insulin secretion, keeping glucose levels within a narrow range. Mutations in the glucokinase gene cause a rare form of diabetes called maturity-onset diabetes of the young (MODY). An early onset (less than 25 years), autosomal dominant inheritance and low insulin secretion stimulated by glucose characterize MODY patients. Specific insulin and proinsulin were measured in serum by immunofluorimetric assays (IFMA) during a 75-g oral glucose tolerance test (OGTT). Two kindreds (SA and LZ) were studied and compared to non-diabetic unrelated individuals (control group 1) matched for age and body mass index (BMI). In one kindred, some of these subjects were also obese (BMI >26 kg/m2), and other family members also presented with obesity and/or late-onset NIDDM. The MODY patients were also compared to a group of five of their first-degree relatives with obesity and/or late-onset NIDDM. The proinsulin profile was different in members of the two MODY kindreds. Fasting proinsulin and the proinsulin/insulin ratio were similar in MODY members of kindred LZ and subjects from control group 1, but were significantly lower than in MODY members of kindred SA (P<0.02 and P<0.01, for proinsulin and proinsulin/insulin ratio, respectively). Moreover, MODY members of family SA had higher levels of proinsulin and proinsulin/insulin ratio, although not significantly different, when compared to their first-degree relatives and to subjects from control group 2. In conclusion, we observed variable degrees of proinsulin levels and proinsulin/insulin ratio in MODY members of two different kindreds. The higher values of these parameters found in MODY and non-MODY members of kindred SA is probably related to the obesity and late-onset NIDDM background present in this family.Hospital Santa CasaHôpital Saint-LouisFondation Jean DaussetUniversidade Federal de São Paulo (UNIFESP)UNIFESPSciEL