Maturity Onset Diabetes of the Young, also known as MODY, is a rare form of diabetes and 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 develop MODY before they're 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 (20,000-40,000 people) in the UK have MODY. It is estimated that about 90% of people with MODY are misdiagnosed with Type 1 or Type 2 diabetes at first.
Common forms of MODY are:
HNF1-alpha, Glucokinase, HNF-1beta, and HNF-4 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, is sometimes picked up during routine screening in pregnancy and is caused by an alteration in the threshold for glucose sensing within cells. Glucokinase carries a much lower risk of complications than other forms of diabetes. Some forms of MODY are associated with kidney cysts and uterine problems (HNF-1beta) or low blood sugar around the time of birth (HNF-4alpha).
It is important to diagnose MODY because it can impact on the type of treatment offered, with some forms of MODY being extremely sensitive to a class of drugs called sulphonylureas, which can negate the need for insulin treatment. Genetic screening for the common MODY genes testing can be done at specialist centres for patients deemed at risk. A diagnosis in a family member will usually lead to screening of other family members with appropriate consent.
For more information about MODY, visit Diabetes Genes or https://www.diabetes.org.uk/Diabetes-the-basics/Other-types-of-diabetes/MODY/