The two most common forms of monogenic diabetes are those called MODY and neonatal diabetes.
MODY type diabetes, of autosomal dominant transmission, is responsible for approximately 1-2% of all causes of diabetes. The diagnosis is usually made before the age of 35 and, unlike type 1 diabetes, it does not usually require insulin treatment. Furthermore, they do not present autoantibodies against pancreatic islets or develop ketoacidosis, while it is common to find evidence of endogenous insulin secretion after the honeymoon period (3-5 years from the onset of diabetes). Unlike type 2 diabetes, it is not usually associated with obesity or acanthosis nigricans. Some forms of the disease produce alterations in lipid metabolism. Responsible mutations are identified in more than 90% of cases in which there is clear suspicion of this disease. The genetic study is useful for the proper management of the disease and to establish the associated prognosis (predictive value) and the differential diagnosis with other more common forms of diabetes. The risk of premature atherosclerotic disease is increased in patients with MODY type diabetes who do not receive timely treatment.
Neonatal diabetes is a rare disease in which diabetes appears in the first six months of life. The most common clinical presentation is marked hyperglycemia and low birth weight due to decreased or absent intrauterine insulin secretion. Neonatal diabetes can be, in turn, temporary or permanent. The diagnosis is made in children under 12 months of age with persistent hyperglycemia (plasma glucose concentration >150-200 mg/dl). Genetic testing confirms the diagnosis and guides management.
On the other hand, hyperinsulinemias and other causes of hypoglycemia, such as congenital hyperinsulinism, are caused by pathogenic variants in many genes that overlap with those related to diabetes. monogenic.