MODY – Maturity Onset Diabetes of the Young

MODY – Maturity Onset Diabetes of the Young

Maturity Onset Diabetes of the Young, also known as MODY, is a rare form of diabetes.  It affects only up to 5% of people with diabetes.1  MODY is different than both type 1 and type 2 diabetes.  It often goes unrecognized or misdiagnosed, which is why seeking an endocrine specialist like Dr. Joshua Smith is very important.

MODY is an inherited form of diabetes that typically manifests itself in adolescents or young adults due to a change (mutation) in one of twenty genes. Many times, MODY is misdiagnosed as type 1 diabetes because the condition is commonly passed down from generation to generation.  If a child has a parent with MODY, they may have a 50% chance of inheriting it regardless of weight, lifestyle, or ethnicity.

Causes and Common Attributes

Like other types of diabetes, MODY limits the body’s ability to produce insulin.  With MODY, the inability to produce insulin is caused by the specific gene mutation.   When our bodies don’t produce enough insulin, an increase in blood glucose levels is probable. High blood glucose levels lead to diabetes.

A few common attributes of MODY include:

  • Dysfunctional use and storage of sugar from food
  • Frequently first noticed in adolescence or early adulthood, usually before age 25
  • Possibly misdiagnosed as type 1 or 2 diabetes
  • No history of diabetic ketoacidosis
  • Negative tests for diabetes antibodies
  • Persistently detectable C-Peptide (a marker of insulin production)
  • Family history of early diabetes in successive generations – grandparent, parent, and child
  • May be treated by diet and medication but does not always require insulin treatment


Like other types of diabetes, MODY causes high blood sugar levels. If untreated, it can lead to complications like:

  • Nerve damage
  • Heart disease
  • Eye damage, including blindness
  • Foot problems
  • Skin problems

Types of MODY

While MODY is caused by the change (mutation) in one of twenty genes, all gene mutations limit the ability for the pancreas to produce insulin, which leads to dangerously high blood-glucose levels.  Each type of MODY may be treated differently and has a unique prognosis, which is why an accurate diagnosis from a pediatric endocrinology expert like Dr. Joshua Smith is imperative.

Of the eleven gene mutations, the following genes, or types of MODY, are the most common:

Mody 1 (HNF4A)


  • Higher than average birth weight
  • Patient may have had low blood sugar at, or soon after, birth
  • Two or three generations of diabetes diagnosed at a young age
  • High sensitivity to sulfonylurea medications


  • Initial treatment may be a sulphonylurea tablet, but some patients may also need to take insulin at some point

Mody 2 (GCK)


  • Fasting sugars of 100-140mg/dl (5.6- 7.5mmol/l) for many years
  • Two or three generations of diabetes diagnosed at a young age
  • A HgbA1c that does not go over 8%
  • Blood sugars rarely ever go above 250mg/dl (14mmol/l)


  • This disease is usually managed through diet and exercise.
  • Medication is not generally prescribed for this type of MODY

Mody 3 (HNF1A)


  • This gene causes about 70% of cases of MODY
  • Low production of insulin, yielding high blood-glucose levels
  • Usually develops in adolescence or early twenties


  • Initial treatment may be a sulphonylurea tablet without the need for insulin
  • Insulin may be necessary in some patients



  • A variety of problems may exist including cysts on the kidneys, uterine abnormalities, and gout
  • Renal cysts may be detected in the womb before a baby is born
  • Usually does not respond well to sulfonylurea tablets


  • This disease is initially managed through a healthy, balanced diet and exercise
  • Diabetes tends to develop later, at which point insulin treatment is usually necessary

How is it diagnosed?

In general, MODY comes on gradually, or there may be no symptoms at all.  The slow onset is one reason the disease can go undetected for long periods of time.  During routine examinations and blood testing, high blood sugar levels may be noticed by a practitioner.

Over time, one may notice one of the following warning signs:

  • Increased thirst or hunger
  • More frequent urination
  • Blurry vision
  • Skin or yeast infections
  • Weight loss
  • Fatigue

If MODY is suspected, additional blood testing may be requested.

When should I seek help?

If you or your child has a family history of early onset diabetes, or you suspect they may have MODY, give Rocky Mountain Diabetes a call, or fill out the form below to request an appointment with Dr. Joshua Smith, who is the region’s only pediatric endocrinologist.  His expertise is invaluable in accurately diagnosing MODY and the specific type and treatment.

If you have MODY and would like to be a part of further research, please contact the University of Chicago MODY Registry.


  1. Harvard Health Publishing

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