Type 1 diabetes
Type 1 diabetes can occur at any age, but is most commonly diagnosed from infancy to the late 30s. With this type of diabetes, a person’s pancreas produces no insulin. It occurs when the body’s own defence system (the immune system) attacks and destroys the insulin-producing cells in the pancreas. What causes the immune system to do this is not yet completely understood, but we are funding world-class research to find out.
The only treatment for type 1 diabetes is insulin, which is usually injected or infused via a pump.
Type 2 diabetes
Type 2 diabetes is by far the most common type of diabetes – in the UK over 90 per cent of people with diabetes have type 2. Type 2 diabetes usually affects those over 40, or 25 if you’re of South Asian descent. However, it is becoming more common among young people. The symptoms of type 2 diabetes are not always obvious and, unlike with type 1, they can take a long time to develop.
People with type 2 diabetes either don’t make enough insulin or don’t make insulin that the body can use properly. The cells in the body become resistant to insulin, making a greater amount of insulin necessary to keep blood glucose levels within a normal range. Eventually, the pancreas can wear out from producing extra insulin, and it may start making less and less.
Type 2 can usually be managed through diet, exercise, and self-monitoring blood glucose, at least in the first few years following diagnosis. However, type 2 diabetes is a progressive condition, and most people will need to take tablets and/or inject insulin after living with it for five to 10 years.
Gestational diabetes usually only affects women during pregnancy. This type of diabetes affects about two to five per cent of pregnant women.
Pregnant women produce large amounts of hormones, which can cause the body to become resistant to the effects of insulin. By the time a woman reaches the end of the third trimester, her insulin requirements have tripled. If the pancreas is unable to match this increased demand, blood-glucose levels start to rise.
In most cases, blood glucose returns to normal after pregnancy. However, women who have had gestational diabetes have a higher risk of eventually developing type 2 diabetes.
Up to a third of people who were initially diagnosed as having type 2 diabetes actually have latent autoimmune diabetes of adults (LADA), sometimes refer to as type 1.5. People with LADA have features of both type 1 and type 2 diabetes – their immune system attacks the cells of the pancreas that produce insulin, but they may also develop insulin resistance.
The destruction of the insulin producing cells is much slower in LADA than in type 1 diabetes. A blood test is needed to tell the difference between type 2 diabetes and LADA.
Some people can manage LADA on diet, exercise and tablets in the initial months or years following diagnosis. However, most with move onto insulin therapy at some point.
MODY – Maturity Onset Diabetes of the Young
MODY is a rare form of diabetes (3% of those diagnosed under the age of 30) that is caused by a change in a single gene. This makes MODY a type of ‘monogenic’ diabetes.
Because half of our genes come from each parent, there is a 1 in 2 chance of inheriting MODY from an affected parent, and it runs strongly in families. However, sometimes the genetic change can develop on its own, without being inherited from a parent.
The most common genes that cause MODY are HNF1A, HNF4A, HNF1B and glucokinase, and the condition behaves differently depending on which gene is affected.
A genetic test can be used to confirm MODY and work out which gene is affected. It is important to know which gene is causing MODY, as treatment varies accordingly. Some forms of MODY may require insulin injections, while others are treated using drugs to boost insulin production in the pancreas. One form of MODY requires no treatment at all.
MODY is typically diagnosed under the age of 25, often with a family history of diabetes.
Neonatal diabetes is a rare form of diabetes that develops in babies under 6 months old. This type of diabetes is caused by a change in a single gene. Treatment for neonatal diabetes varies depending on which gene is affected.
Neonatal diabetes may either be transient or permanent. Transient neonatal diabetes typically disappears during infancy, but may reappear during adolescence. Permanent neonatal diabetes is a lifelong condition.
A genetic test can be used to confirm neonatal diabetes, and work out which gene is affected. It is important to know which gene is causing neonatal diabetes, as treatment varies accordingly. Some forms of neonatal diabetes may require insulin injections, while others are treated using drugs to boost insulin production in the pancreas.
N.B. Because it’s very rare, babies with neonatal diabetes may mistakenly be diagnosed with type 1 diabetes. Evidence suggests however that type 1 diabetes is not found in babies under 6 months old. If you or your child were diagnosed with diabetes under the age of 6 months, speak to your healthcare team. Genetic testing can be used to identify cases of neonatal diabetes.