Insulin resistance type A syndrome ..., (Type A insulin resistance syndrome) - Gen INSR.
The resistance syndrome type A insulin is a rare disorder characterized by intense insulin resistance, a condition in which the tissues and organs of the organism do not respond properly to the hormone insulin. Insulin normally helps regulate glucose levels in the blood by controlling the amount of glucose passing blood cells to be used as energy. In people with the disease, insulin resistance affects the regulation of blood glucose and ultimately leads to diabetes, in which glucose concentrations in blood can become dangerously high.
In the women concerned, the main characteristics manifest themselves in adolescence. Many women affected with primary amenorrhea, oligomenorrhea, development of ovarian cysts and hirsutism. In addition, women most affected also develop acanthosis nigricans. Unlike most affected, women with type A usually not overweight. In males, the signs and symptoms of the disease are more subtle. Some men have hypoglycemia as the only sign, although others may also have acanthosis nigricans. In many cases, affected males come to the doctor only when they develop diabetes in adulthood.
The resistance syndrome type A insulin is one of a group of related inherited syndromes described as intense insulin resistance disorders. These changes, which also include Donohue syndrome and Rabson-Mendenhall syndrome, are considered part of a spectrum. The resistance syndrome type A insulin represents the mildest of the end and, frequently, their characteristics do not appear until puberty or later. Usually, this disease is not life threatening.
This process is due to mutations in INSR gene, located on the short arm of chromosome 19 (19p13.3-p13.2). This gene encodes a so - called insulin receptor, which is found in many cell types protein. Insulin receptors are found in the outer membrane surrounding the cell, where they bind to circulating insulin in the bloodstream. This triggers signaling pathways that influence binding many cellular functions.
The INSR genetic mutations, responsible for the syndrome, resistance type A insulin alter the function of the insulin receptor. Although insulin is present in the bloodstream, defective receptors make it less able to exert their effects on cells and tissues. This intense the effects of insulin resistance affects the regulation of blood sugar and leads to diabetes mellitus. In the women affected, excess insulin in the bloodstream interacts with hormonal factors during adolescence causing menstrual disorders, ovarian cysts, and other characteristics of the disease.
The resistance syndrome type A insulin can be inherited in an autosomal dominant pattern or, less frequently, with an autosomal recessive pattern. In autosomal dominant inheritance, a copy of the altered gene in each cell is sufficient to express the disease. In some cases, an affected person inherits the mutation from an affected parent. Other cases are due to new mutations in the gene and occur in people with no history of disease in your family. In the autosomal recessive both gene copies in each cell must have mutations for alteration is expressed. The parents of an individual with an autosomal recessive disease have a copy of the mutated gene, but usually show no signs and symptoms of the disease.
Tests in IVAMI: in IVAMI perform detection of mutations associated with resistance type A insulin, complete syndrome by PCR amplification of the exons of the gene INSR, and subsequent sequencing.
Samples recommended: EDTA blood collected for separation of blood leukocytes, or impregnated sample card with dried blood (IVAMI may mail the card to deposit the blood sample).