In addition to type 1 and type 2 diabetes, other forms occur. For example, it is estimated that 2 to 5% of people with diabetes have a hereditary form, which is often missed by doctors.  A well-known group in this are the monogenetic forms of diabetes, formerly known as MODY.

MODY stands for Maturity Onset Diabetes of the Young, loosely translated "Adolescent Diabetes. This name comes from the time when it was not known exactly what MODY was. People recognized something special: you got it at a young age, but it looked like maturity onset diabetes. Nowadays we know several, but probably not all, forms of MODY and we call it monogenetic diabetes, because in this form one gene defect is the cause. This is very different in type 1 and type 2 diabetes, where many hereditary factors play a role (polygenetic diabetes). 


  1. Too young for type: Monogenetic diabetes, unlike traditional type 2 diabetes, usually starts early in life, usually before age 25, almost always before age 40. It is often discovered at special stages, such as puberty, pregnancy, long periods of illness.

  2. Hereditary: Diabetes usually occurs in successive generations: child - parent - grandparent. Sometimes this is not immediately obvious, because monoenetic diabetes was not always recognized in the past. 

  3. Too special' for type 2: different treatment and course: In treatment, sometimes it is noticed that the diabetes is easier to control with insulin (low dose needed). Or there is no excess weight at all and then type 2 diabetes is more unlikely. MODY diabetes, if not properly controlled, can be just as serious as other forms of diabetes. E.g., it can also cause complications. This is true even with MODY-2, which is mostly mild but sometimes has the diabetes characteristics. 


Monogenetic diabetes runs in families and successive generations because it is hereditary. It occurs because one hereditary factor (gene) that has something to do with insulin and glucose regulation deviates, which can cause diabetes. For example, monogenetic diabetes occurs because the gene responsible for being able to "sense" glucose levels is deft (MODY 2) or because of a defective gene that helps deliver the insulin into the blood. In all other forms of diabetes, heredity also plays a role, but then lots of different genes are involved. 
The genes that may play a role in monogenetic diabetes are passed from parents to children. If one of the parents has monogenetic diabetes, the children have a 50% chance of also having this form of diabetes. This is called 'dominant inheritance (autosomal dominant) and if you inherit a healthy gene from one parent and a MODY gene from the other you do get the disease, because the MODY gene is then dominant.


It is important to know if you have MODY or if MODY runs in the family. MODY can reveal itself at many different ages. Sometimes when you are 8 years old, sometimes when you are 35. Treating it in time, as with any form of diabetes, is very important. Diabetes is not something you should have on the sly. It makes you more likely to have complications. Some forms of MODY are sometimes accompanied by other abnormalities, such as MODY 5 in which kidney abnormalities sometimes occur. These are conditions for which additional tests and treatments are helpful and necessary.


Sometimes after being diagnosed with MODY, diabetes treatment can be done very differently and you can switch to tablets instead of insulin. This can be figured out with tests. Such treatments are often different from the standard tablet treatment of type 2 diabetes (via metformin). In MODYs, especially during times of "high demand" for insulin, diabetes may develop or be more difficult to treat, such as during puberty and pregnancy. Then insulin treatment is sometimes necessary (temporarily). 


It is also important for family members to know about your or your child's diagnosis of MODY. After all, this hereditary form can also be present in family members, even if there is no diabetes at present. It can be seen as a disadvantage that, if you think you have nothing wrong with you, you are suddenly confronted with diabetes. On the other hand, timely treatment is of vital importance and (as mentioned) it is better to be warned than to have diabetes 'secretly'. Hereditary research can also show that you are not a carrier, so you will never get MODY. Of course, family members must decide for themselves whether they want to have such research done or not. 


It can take years before the correct diagnosis is made, often the clinical picture is mistaken for type 1 or type 2 diabetes. The official diagnosis can only be obtained through DNA testing, after which it can take up to 3 months before the results are known.  But the suspicion that it is a form of MODY, we at Diabeter can start investigating much earlier.

We examine our patients for monogenetic diabetes if there are indications that it is not type 1 or 2. This could be, for example, if someone who is quite slim was nevertheless diagnosed with type 2 diabetes, or if diabetes occurs in every generation without indications (autoantibodies, clinical picture at diagnosis) for type 1, or if the diabetes started before the first birthday. Also, for example, a low insulin requirement may be a reason to look further or the occurrence of other conditions.

Milkshake test

With the help of a milkshake test (the so-called Mixed Meal Tolerance Test) we can determine whether you still have insulin-producing beta cells. You will drink a special milkshake, after which your blood sugar level will rise. If you still have insulin-producing beta cells, they will respond by administering tablets with repaglinide and start producing (some) insulin.

Better treatment

In recent times the diagnosis has been adjusted in this way in about thirty people. But perhaps more importantly, it will then also be possible to examine whether the treatment can be improved by using tablets instead of injections.