Who needs an examination of the genetic predisposition to diabetes.
Genetically determined hereditary forms of diabetes mellitus (DM) occur in about 2% of cases. These, similar to the clinical course of the form, have been isolated in a separate group - adult diabetes mellitus in young people, or MODY-diabetes (maturity onset diabetes of the young).
They are grouped into one group on the basis of a common feature: the disorder is associated with mutations in the insulin-encoding gene or in the genes responsible for the development, functioning and regulation of the work of β-cells of the pancreas, as well as for insulin sensitivity.
Found at least eight genes responsible for the development of this form of diabetes.
MODY-diabetes is inherited by the autosomal dominant type, characterized by insulin-dependent flow and early onset (usually up to 25 years).
Clinical manifestations and severity of the course depend on how seriously the genes are damaged.
Usually MODY-diabetes remains undiagnosed, it is mistakenly classified as diabetes mellitus type 1 or 2. But since the correct statement of the diagnosis depends not only on the treatment and prognosis for the patient, but also the identification of the disease at an early stage among the members of his family and the identification of risks for them.
Than MODY-diabetes differs from SD 1 and 2 types
The age when it manifests itself is not characteristic of either 1 or 2 type. In addition, when it does not detect autantyantili to cells of the pancreas, as with type 1.
The diagnosis of type 2 diabetes must also be questioned, as young patients, as a rule, they are not overweight, insulin resistance is not expressed.
Mutations in the glucokinase gene
Glucokinase is an enzyme that is involved in the process of glucose formation from glucose. It is in the form of glycogen carbohydrates stored in the body.
In addition, glucokinase is involved in the mechanism of feedback with beta-cells of the pancreas, providing insulin release to the pancreas in response to an increase in blood glucose levels.
When mutation of the glucokinase gene in the liver does not store glycogen. On the contrary, the liver produces an increased amount of glucose, as the broken feedback mechanism. This is associated with a moderate increase in blood glucose levels in the morning.
As a result of mutations in the glucokinase gene in children, a mild, latent, current form of diabetes, characterized by persistent hyperglycemia and insignificant glucosuria, is formed in children.
In the genetic examination of children with asymptomatic glucosuria, in 59% of them, mutation of the glucokinase gene was detected.
Such violations are usually found during a routine examination, and in collecting a family history, in most cases, it turns out that the child has relatives who suffer from a mild type of type 2 diabetes or undergo gestational diabetes. This, of course, does not apply to children with newly-occurring mutations.
Also, this mutation is very common in women with gestational diabetes mellitus. As a rule, these patients also receive insulin therapy during pregnancy, but despite this, the fetus is still born large.
Mutations in the HNF 1 A and HNF 4 A genes
The HNF 1A and HNF 4A genes encode the factors necessary for the proper development of the pancreas and the differentiation of β-cells.
Diabetes caused by mutations in these genes, in clinical terms, is very similar to the picture of the progressive defeat of β-cells.
Due to these mutations, MODY-diabetes is well suited for treatment with low doses of sulfanilicure.
HNF mutation 1A is the most common cause of MODY-diabetes, accounting for approximately 52% of patients. In the presence of this mutation, CD develops up to 25 years in 63% of mutation carriers, and up to 50 years - in 94%. It also has a low glucose filtration threshold, so glucosuria is even observed in patients with normal levels of glucose in the blood.
The share of HNF 4 Amutaci accounts for about 10% of patients with MODY-diabetes. The clinical picture is very similar to the inherent HNF 1Amutatsii. In addition, a sign of the presence of HNF 4Amutatsii can serve as a paradoxical macro-syndrome (increase in size) of the fetus and transient neonatal hyperglycemia (increased glucose in the newborn's blood).
Diagnosis of MODY-diabetes
When diagnosing it is important to correctly differentiate it from other types of diabetes. This is done by studying the levels of the C-peptide and the glucose tolerance test.
The most accurate method for diagnosing MODY-diabetes is to conduct genetic testing. When detecting a mutation in a patient, it is necessary to examine the members of his family in order to detect hyperglycemia in them and to conduct further genetic research.
This approach will allow timely initiation of adequate treatment and reduce the risk of complications from relatives of a patient who has not been diagnosed.