Arch. Endocrinol. Metab. 2018;62(1):4-5
(Epi) Genetics and the complexity of diabetes mellitus
DOI: 10.20945/2359-3997000000002
Both type 1 (T1D) and type 2 (T2D) diabetes mellitus are complex diseases to which environmental and genetic factors contribute (). Recently, epigenetic factors have also been recognized as important not only in the etiopathogenesis of these conditions, but also in the development of their chronic complications (). As if the interaction among environment, genetics and epigenetics is not complex enough, each of these factors has their own complexity. For instance, regarding the genetic setting, both T1D and T2D are polygenic diseases for which several susceptibility genes contribute, each with a relatively small participation (). In addition, susceptibility genes may vary among different populations, reason why genetic studies should be reproduced in the population of interest.
In this issue of Archives of Endocrinology and Metabolism (AE&M), two manuscripts address, respectively, genetic and epigenetic factors associated with diabetes. Pirozzi and cols. () evaluated in a population of Brazilian obese patients from the Southeast region, the association of T2D with two polymorphisms, rs1799752 in the gene encoding angiotensin I converting enzyme (ACE) and rs1801133 in the gene encoding methylenetetrahydrofolate reductase (MTHRF). MTHRF is the enzyme that catalyzes the conversion of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate whose deficiency increases plasmatic homocysteine concentrations. Both polymorphisms had been previously studied for the association to T2D with conflicting results in different ethnic groups (,). No association of these polymorphisms with T2D was found by Pirozzi and cols., in agreement with a previous study performed in Brazilian patients from the South region, which also did not find association of T2D with rs1799752 in the ACE gene (). Given the admixture which characterizes the Brazilian population and the distinct genetic background even among the different Brazilian regions (), it is important that such genetic studies are carried out, preferably in larger series of patients.
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