Desvendando a relação entre Síndrome de Down e diabetes mellitus

Abstract

Down syndrome (DS) is a cytogenetic condition resulting from an abnormality of the acrocentric autocentric chromosomes of pair 21, during cell division, which manifests itself in three distinct forms: simple trisomy, mosaicism and Robertsonian translocation. According to current records, in Brazil, there are approximately 300 thousand people with DS and, worldwide, about more than 5 million cases. DS has the following phenotypic expressions: upward oblique eyelid folds, epicanthus, synophris (union of the eyebrows), flattened face, lingual protrusion, high palate, low ears, small pinna, clinodactyly of the 5th finger, brachydactyly (short fingers), spacing between the 1st and 2nd toes, simian fold (single transverse palmar fold), hypotonia, ligament laxity, excess fatty tissue on the dorsum of the neck, retrognathia, diastasis (distancing) of the rectus abdominis muscles, umbilical hernia, brachycephaly, almond-shaped eyes, and mental retardation. In addition to these conditions affecting anatomically and physiologically, it can also compromise the immune system of these individuals, predisposing them to the development of other conditions, such as Diabetes Mellitus (DM). DM is characterized by the excessive presence of glucose in the circulating blood, caused by deficiency or ineffectiveness of insulin action, and may have an autoimmune origin (DM1) or be the result of insulin resistance (IR), and may progress to DM2 without appropriate treatment. In this study, through a narrative review with a qualitative approach, the relationship between both conditions was investigated, since individuals with DS are four times more likely to express DM compared to normal individuals. The study revealed that DM1 is more common in DS carriers, being associated with thymus malformations that affect genes that regulate the immune system present on chromosome 21, such as the AIRE gene, which, when mutated, decreases the release of T lymphocytes, favoring the emergence of DM1. DM2 is expressed in a smaller proportion, but it is justified by dyslipidemia and its etiologies, which are frequent in these aberrants, due to exposure to external irregularities. It should be noted that IR is also a reality in these individuals with DS, to the detriment of the development of metabolic syndrome.