Maturity Onset Diabetes of the Young (MODY)

Maturity Onset Diabetes of the Young, also known as MODY or monogenic diabetes, is a rare form of diabetes. It is caused by a mutation, or change, in a single gene. If a parent has this gene mutation their children have a 50% chance of inheriting it from them. They will generally go on to develop MODY before they are 25, whatever their weight, lifestyle or ethnic group.

MODY is very rare compared with type 1 and type 2 diabetes. Experts estimate that only 1–2% of people with diabetes in the UK (20,000–40,000 people) have MODY. It is estimated that about 90% of people with MODY are misdiagnosed with type 1 or type 2 diabetes at first.

There are several different types of MODY. Genetic testing is required to diagnose which type you have. The most common forms are HNF1-alpha, glucokinase, HNF1-beta and HNF4-alpha, although there is a growing list of other, rarer types. The names relate to the genes affected.

Glucokinase tends to be associated with a milder form of diabetes and is sometimes picked up during routine screening in pregnancy. It carries a much lower risk of complications than other forms of diabetes. Some forms of MODY are associated with kidney cysts and uterine problems (HNF1-beta) or low blood glucose around the time of birth (HNF4-alpha).

If your doctor or diabetes care team suspects you might have MODY they will discuss genetic testing with you. It is important to diagnose which particular type you have as you may be able to have your insulin treatment replaced with a glucose-lowering tablet. It may be advisable for family members to be tested too.

More information on MODY is available on the Diabetes UK website here.