Maturity onset diabetes of youth (MODY) is a form of hereditary diabetes that may present at an early age and which may be confused with Type 1 or Type 2 diabetes. It should be considered whenever there is a family history of diabetes or "atypical" diabetes in a young patient.


Clinical features:

(1) The presence of a strong family history of diabetes, involving at least 3 generations and/or with evidence of autosomal dominant inheritance.

(2) The onset of hyperglycemia as a child, adolescent or young adult, with slow progression to clinical diabetes over many years.

(3) Many patients are not obese.

(4) Insulin resistance is uncommon (unless the patient also has obesity-related Type 2 diabetes).

(5) Patients show a delayed and subnormal insulin secretory response, with insulin insufficiency (page 590, Fajans).

(6) Patients show a low rate of ketosis.


The syndromes are caused by the presence of a mutation that impairs beta cell function in the pancreas. Several mutations have been identified but others still need to be described.




hepatocyte nuclear factor (HNF) 4-alpha


glucosekinase gene


hepatocyte nuclear factor (HNF) 1-alpha


insulin promoter factor 1


hepatocyte nuclear factor (HNF) 1-beta


The level of hyperglycemia is usually mild and can be controlled by diet and/or use of hypoglycemic agents. Some patients may have severe insulin deficiency (? double dose) and require insulin therapy.


A young child may be misdiagnosed as having insulin-dependent diabetes (Type 1). Insulin therapy may be unnecessary in these patients and may be associated with excessive morbidity.


It is important to distinguish MODY from Type 2 diabetes that occurs in obese children with insulin resistance. An obese child from a family with a MODY mutation may have both forms of diabetes.


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