RESUMO
Type 2 diabetes mellitus is a complex metabolic disorder resulting from the action and interaction of many genetic and environmental factors. It has been reported that polymorphisms in genes involved in the metabolism of glucose are associated with the susceptibility to develop type 2 diabetes mellitus. Although the risk of developing type 2 diabetes mellitus increases with age, as well as with obesity and hypertension, its prevalence and incidence are different among geographical regions and ethnic groups. In Mexico, a higher prevalence and incidence has been described in the south of the country, and differences between urban and rural communities have been observed. We studied 73 individuals from Santiago Jamiltepec, a small indigenous community from Oaxaca State, Mexico. This population has shown a high prevalence of type 2 diabetes mellitus, and the aim of this study was to analyze the relationship between the Pst I (insulin gene), Nsi I (insulin receptor gene) and Gly972Arg (insulin receptor substrate 1 gene) polymorphisms and type 2 diabetes mellitus, obesity and hypertension in this population. Clinical evaluation consisted of BMI and blood pressure measurements, and biochemical assays consisted of determination of fasting plasma insulin and glucose levels. PCR and restriction enzyme digestion analysis were applied to genomic DNA to identify the three polymorphisms. From statistical analysis carried out here, individually, the Pst I, Nsi I and Gly972Arg polymorphisms were not associated with the type 2 diabetes, obese or hypertensive phenotypes in this population. Nevertheless, there was an association between the Nsi I and Pst I polymorphisms and increased serum insulin levels.
Assuntos
Diabetes Mellitus Tipo 2/genética , Hipertensão/genética , Obesidade/genética , Polimorfismo de Fragmento de Restrição , Adulto , Antígenos CD , Glicemia/análise , Índice de Massa Corporal , DNA/genética , Desoxirribonucleases de Sítio Específico do Tipo II , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/epidemiologia , Etnicidade , Feminino , Frequência do Gene , Genótipo , Humanos , Insulina/sangue , Insulina/genética , Proteínas Substratos do Receptor de Insulina , Masculino , México/epidemiologia , México/etnologia , Fosfoproteínas/genética , Reação em Cadeia da Polimerase , Prevalência , Receptor de Insulina/genéticaRESUMO
The metabolic or insulin resistance syndrome, characterized by hypertension, dyslipidemia, glucose intolerance and hyperinsulinemia, may have genetic determinants. The insulin gene (INS), insulin receptor gene (INSR) and insulin receptor substrate 1 gene (IRS1) have been proposed as candidate genes. We examined eight polymorphisms in these genes in 163 individuals from Yucatan, Mexico; this population has a high prevalence of obesity, type 2 diabetes mellitus and dyslipidemia. Subjects were evaluated for body mass index (BMI) and blood pressure. Blood samples were collected to determine glucose, insulin, triglycerides and cholesterol levels, as well as for DNA isolation. Restriction fragment length polymorphisms in INS, INSR and IRS1 were identified by polymerase chain reaction and digestion with selected restriction enzymes. Among the eight polymorphisms analyzed, the PstI polymorphism in INS was significantly associated with hypertriglyceridemia and with the presence of at least one abnormality related to the metabolic syndrome (P=0.007 and 0.004, respectively). The MaeIII polymorphism in INS was associated with fasting hyperinsulinemia (P=0.045). In multilocus analyses including both INS polymorphisms, significant associations were seen with hypertriglyceridemia (P=0.006), hypercholesterolemia (P=0.031) and with presence of at least one metabolic abnormality (P=0.009). None of the polymorphisms in INSR or IRS1 was associated with any of these traits. These findings suggest that the insulin gene may be an important determinant of metabolic syndrome, and particularly of dyslipidemia, in this population.
Assuntos
Diabetes Mellitus Tipo 2/genética , Insulina/genética , Síndrome Metabólica/genética , Fosfoproteínas/genética , Polimorfismo Genético , Receptor de Insulina/genética , Adolescente , Adulto , Alelos , Estudos de Casos e Controles , Feminino , Frequência do Gene , Humanos , Hipercolesterolemia/genética , Hiperinsulinismo/genética , Hipertrigliceridemia/genética , Proteínas Substratos do Receptor de Insulina , Masculino , México , Pessoa de Meia-IdadeRESUMO
We undertook an association analysis between the ile50val, glu375ala, cys406arg, and ser761pro polymorphisms of the IL-4Ralpha gene and atopic asthma, total IgE levels and IL-4 serum levels in a population from western Mexico. We found that the ser761pro polymorphism was monomorphic for ser761, while there was no association between any of the other polymorphisms and the three phenotypes analysed.
