Maturity-onset diabetes of the young (MODY) [15 genes]

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. The genetic study is useful for the adequate management of the disease and to establish the associated prognosis (predictive value) and the differential diagnosis with other more common forms of diabetes. Responsible mutations are identified in more than 90% of cases in which there is clear suspicion of this disease. Some forms of the disease also cause alterations in lipid metabolism. The risk of premature atherosclerotic disease is increased in patients with MODY-type diabetes who do not receive timely treatment.

They constitute approximately 1-2% of all causes of diabetes

The correct diagnosis of MODY is very useful because it defines the subtype of diabetes and can condition the type of treatment depending on the type of alteration found. Furthermore, the identification of the mutation in the index case allows the rest of the family to be studied and other family members at risk who do not yet present clinical manifestations to be identified.

Patients with early-onset diabetes (generally <35 years) and who present:

• Atypical features for type 1 diabetes mellitus including absence of pancreatic islet autoantibodies, evidence of endogenous insulin production beyond the “honeymoon period”, measurable C-peptide in the presence of hyperglycemia, low requirement for insulin treatment , absence of ketoacidosis in the absence of insulin treatment.
• Atypical features for type 2 diabetes mellitus include the following: onset of diabetes before age 45, absence of significant obesity, absence of acanthosis nigricans, normal triglyceride levels and/or normal or elevated HDL-C.
• Mild and stable fasting hyperglycemia that does not progress or respond appreciably to pharmacological therapy.
• Extreme sensitivity to sulfonylureas.
• Extrapancreatic characteristics (renal, hepatic, gastrointestinal).
• Personal or family history of neonatal diabetes or neonatal hypoglycemia.
• Family history of diabetes consistent with an autosomal dominant inheritance that contrasts with type 1 diabetes and type 2 diabetes.