In addition to Type 1 and Type 2, there is a wide variety of other types of diabetes.
Maturity onset diabetes of the young (MODY)
MODY is a rare form of diabetes which is different from both Type 1 and Type 2 diabetes, and runs strongly in families. MODY is caused by a mutation (or change) in a single gene. If a parent has this gene mutation, any child they have, has a 50% chance of inheriting it from them. If a child does inherit the mutation, they will generally go on to develop MODY before they’re 25, whatever their weight, lifestyle, ethnic group etc. The key features are: Being diagnosed with diabetes under the age of 25. Having a parent with diabetes, with diabetes in two or more generations. Not necessarily needing insulin. MODY is very rare compared with Type 1 and Type 2 diabetes – experts estimate that only 1-2% of people with diabetes (20-40,000 people) in the UK have it. But because MODY is so rare, doctors may not be aware of it, so it’s estimated that about 90% of people with it are mistakenly diagnosed with Type 1 or Type 2 diabetes at first. The most common types of MODY are:
- HNF1-alpha. This gene causes about 70% of cases of MODY. It causes diabetes by lowering the amount of insulin made by the pancreas. Diabetes usually develops in adolescence or early twenties, and people with HNF1-alpha MODY generally don’t need to take insulin, they can be treated with small doses of a group of tablets called sulphonylureas (often used in Type 2 diabetes).
- HNF4-alpha. This isn’t as common as the other forms of MODY. People who have inherited a change in this gene are likely to have had a birth weight of 9lb or more (around 4 kg). They may also have had a low blood sugar at, or soon after, birth which might have needed treatment. people with HNF4-alpha are generally treated with a sulphonylurea tablet but may progress on to needing insulin.
- HNF1-beta. People with this type of MODY can have a variety of problems including renal cysts (cysts of the kidneys), uterine abnormalities and gout as well as diabetes. Often the renal cysts can be detected in the womb before a baby is born. The diabetes tends to develop later and insulin treatment is usually necessary, as well as following a healthy balanced diet and getting regular physical activity. HNF4-beta MODY also carries a risk of complications of diabetes.
- Glucokinase. This gene helps the body to recognise how high the blood glucose level is in the body. When this gene isn’t working properly the body allows the level of blood glucose to be higher than it should be. Blood glucose levels in people with glucokinase MODY are typically only slightly higher than normal, generally between 5.5-8mmol/l. You don’t generally have symptoms of this type of MODY and so it’s often picked up through routine testing (eg during pregnancy). You don’t need any treatment for glucokinase MODY.
All types of MODY apart from glucokinase carry a risk of the long-term complications of diabetes so you should follow a healthy balanced diet and keep physically active as this helps to maintain good blood glucose and cholesterol levels which in turn reduce the risk of complications. It’s important to know if you’ve got MODY, for the following reasons:
- To make sure you get the right treatment and advice for your type of diabetes (eg stopping insulin).
- As there is a 50% chance of a parent passing on MODY to their child, you can consider and discuss the risk to any children you have/plan to have.
- Genetic testing can be offered to other family members
If you think you might have MODY you should discuss testing with your doctor. Testing involves:having blood taken for pancreatic antibodies and blood or urine tested for C-peptide (your doctor/hospital can do this). Having blood taken for genetic testing. Your doctor/hospital will take the blood from you, but they will send it on to the specialist centre in Exeter for it to be tested, along with details of your diagnosis and treatment.
For more info go to www.diabetesgenes.org.
Gestational diabetes mellitus (GDM) is a type of diabetes that arises during pregnancy (usually during the second or third trimester). In some women, GDM occurs because the body cannot produce enough insulin to meet the extra needs of pregnancy. In other women, GDM may be found during the first trimester of pregnancy. In these women, the condition most likely existed before the pregnancy. A test called an Oral Glucose Tolerance Test (OGTT) is used to diagnose GDM. An OGTT involves a blood test before breakfast, then again two hours after a glucose drink. At the booking appointment you will be assessed for risk factors that can make you more likely to have gestational diabetes. These include:
- a family history of Type 2 diabetes (parent, brother or sister)
- an unexplained stillbirth or neonatal death in a previous pregnancy, and/or
- a very large infant in a previous pregnancy (4.5kg or over)
- you have had gestational diabetes before
- your family origin is South Asian, Black Caribbean or Middle Eastern.
If you have any of these characteristics you should be offered a test for gestational diabetes.
In most cases, Gestational diabetes comes to light during the second trimester of pregnancy. Since the baby’s major organs are fairly well developed at this stage, the risk to the baby is lower than for women with Type 1 or Type 2 diabetes. However, babies of women who had blood glucose problems that were undiagnosed before pregnancy, have a higher risk of malformations.
Treating gestational diabetes: Often, blood glucose levels can be controlled by diet. You will be referred to a dietitian who will advise you about healthy eating. If your blood glucose cannot be controlled by diet, you may need tablets or insulin to treat your diabetes the degree of risk depends on how long blood glucose levels have been high and on how high the levels have been. Blood glucose target levels are the same as for women with Type 1 or Type 2 diabetes and you will receive the same specialised care as they do. Before you are discharged to the care of your GP, your blood will be tested to make sure the glucose levels have returned to normal. Usually gestational diabetes goes away after your baby is born. Before you are discharged to the care of your GP, your blood will be tested to make sure the glucose levels have returned to normal. You should have a fasting blood test six weeks after your baby is born and then every year. If you took medication (tablets or insulin) during your pregnancy, you will be able to stop them after your baby is born.
You are more likely to develop GDM again if you have had it in previous pregnancies, and women with GDM have an increased risk of developing Type 2 diabetes during their lifetime.
Alström Syndrome is a rare genetically inherited syndrome which has a number of common features. It's common features are: Retinal degeneration: This is often the first feature of Alström Syndrome that is noticed. Children have nystagmus (wobbly eyes) and photophobia (extreme sensitivity to light). Poor vision can be present even in small babies, and gradual vision loss can lead to blindness. Hearing loss: This is usually noticed before the age of 10. The severity of hearing loss in Alström Syndrome varies considerably.
Cardiomyopathy: This means that the heart doesn’t pump as well as it should. It can improve, although not completely, and it can recur in later life. Obesity: children and young people with Alstrom syndrome have a lower energy requirement and generally are less active compared with their peer group and as a result have a higher risk of obesity. This weight gain tends to be less severe in later life Type 2 diabetes
: In young adulthood, children with Alström Syndrome tend to become resistant to insulin, and can go on to develop Type 2 diabetes. High blood fat levels are also common in people with insulin resistance. Renal (kidney) failure. This might be acute (happening quickly) or chronic (happening over a long period of time). There are a number of reasons why the kidneys fail, one of these is diabetes. Orthopaedic and rheumatology problems. People with Alström Syndrome can have problems with their bones and joints. These include curvature of the spine, spondylitis (excessive thickening of the spine), arthritis and short stature. Other problems such as hypogonadism (defects of the reproductive system), undescended testes, low testosterone, polycystic ovaries under-active thyroid and acanthosis nigricans (dark patches of skin) may also be present.
There isn’t a cure for Alström Syndrome but there are treatments for some of the features.
Sensitivity to bright light can be helped by wearing dark glasses, which may also slow down retinal degeneration as well. Hearing aids can be helpful in managing hearing loss. A number of drugs can be used to treat cardiomyopathy, including digoxin, frusemide and ACE inhibitors. Following a healthy balanced low energy diet and taking regular physical activity are important to keep weight under control and will usually be the first treatment for Type 2 diabetes. Medications such as metformin, sulphonylureas and insulin can be used to treat Type 2 diabetes if weight management and physical activity are unsuccessful. The treatment for renal (kidney) failure depends on how well the kidneys are working, but dialysis and kidney transplants are available should they fail completely. Physical activity, stretching exercise s, and massage can help with bone and joint problems.
Alström Syndrome is very rare, and estimates suggest there are only around 700 people diagnosed with it worldwide. But Alström UK (the charity for people affected by Alström Syndrome) estimate that up to 200 families in the UK may be affected, but because of it’s rarity many have not been identified.
Alström syndrome can be diagnosed from the features above, but there is also a genetic test that can be done. Scientists have identified a gene that causes Alström Syndrome which is recessive, which means that the gene must be passed on by both parents.
Where can I go for more information?
Specialist Alström clinics take place at Birmingham Children’s Hospital and Torbay Hospital in Devon.
Alström Syndrome – a guide to greater understanding of this rare condition http://www.alstrom.org.uk/wp-content/uploads/2011/06/medical-handbook-2010.pdf
Expert opinion from Hazel Rigall, Specialist Dietitian (Diabetes and Endocrinology), Birmingham Children’s Hospital:
Children and young people with Alstrom syndrome have a lower energy requirement and generally are less active compared with their peer group and as a result have a higher risk of obesity. This weight gain tends to be less severe in later life
Following a healthy balanced low energy diet and taking regular physical activity are important to keep weight under control and will usually be the first treatment for Type 2 diabetes.
Neonatal diabetes is a form of diabetes that is diagnosed under the age of six months. It’s a different type of diabetes than the more common Type 1 diabetes as it’s not an autoimmune condition (where the body has destroyed its insulin producing cells). Neonatal diabetes is caused by a change in a gene which affects insulin production. This means that level of blood glucose (sugar) in the body rise very high. The main feature of neonatal diabetes is being diagnosed with diabetes under the age of 6 months, and this is where it’s different from Type 1, as Type 1 doesn’t affect anyone under 6 months. As well as this, about 20% of people with neonatal diabetes also have some developmental delay (eg muscle weakness, learning difficulties) and epilepsy. Neonatal diabetes is very rare, currently there are less than 100 people diagnosed with it in the UK. There are two types of neonatal diabetes – transient and permanent. As the name suggests, transient neonatal diabetes doesn’t last forever and usually resolves before the age of 12 months. But it usually recurs later on in life, generally during the teenage years. It accounts for 50-60% of all cases. Permanent neonatal diabetes as you might expect, lasts forever and accounts for 40-50% of all cases. Most people with neonatal diabetes don’t need insulin and can be treated with a tablet called Glibenclamide instead. Glibenclamide is a drug that is more commonly used to treat Type 2 diabetes, though to treat neonatal diabetes you need much higher doses than you would for Type 2. As well as controlling blood glucose levels, Glibenclamide can also improve the symptoms of developmental delay. It’s important to know if you have/your child has neonatal diabetes to make sure you’re/they’re getting the right treatment and advice (eg stopping insulin). So if you were/your child was diagnosed with diabetes before you/they were 6 months old, ask your diabetes team for a test for neonatal diabetes. Your team can take a blood sample and send it to the Peninsula Medical School based at the Royal Devon and Exeter Hospital for analysis. The test is free. Go to www.diabetesgenes.org. This site will also tell your doctor how to take your blood and send it to the team at Exeter.
Wolfram Syndrome is a rare genetic disorder which is also known as DIDMOAD syndrome after its four most common features (Diabetes Insipidus, Diabetes Mellitus, Optic Atrophy and Deafness)
What are the features of Wolfram Syndrome?
- Diabetes mellitus: This is a different type of diabetes than the more common Type 1 as it’s not an autoimmune condition (where the body has destroyed the insulin producing cells). You also don’t tend to get microvascular complications like retinopathy (which can cause blindness) or nephropathy (which can cause kidney failure). But it’s treated in the same way as Type 1 diabetes with insulin injections, blood testing, following a healthy balanced diet and getting regular physical activity. Everyone with Wolfram Syndrome is likely to have diabetes at some point.
- Diabetes insipidus: This is where the body can’t concentrate urine because the posterior pituitary gland (found at the base of the brain) isn’t making enough of the hormone vasopressin. This means that you get very thirsty and need to pass urine frequently and your urine is very dilute. About ½ of people with Wolfram Syndrome have Diabetes insipidus.
- Optic atrophy: This means that the optic nerve has wasted away and causes colour blindness and gradual loss of vision. Everyone with Wolfram Syndrome will have optic atrophy at some stage.
- Deafness: It can be difficult to hear high pitched sounds or to hear in a crowded room. About 2/3 of people with Wolfram Syndrome will have hearing loss and about ¼ of these will need a hearing aid.
- Renal problems: This can cause bedwetting, needing to pass urine frequently and loss of bladder control. Even when the symptoms of either type of diabetes are controlled, you can still get these symptoms, as they are caused by a problem with the renal tract. About two thirds of people with Wolfram Syndrome have renal problems.
- Neurological problems: These can include loss of balance, sudden muscle jerks, loss of taste and smell, breathing problems and depression. About a quarter of people with Wolfram Syndrome may have a mental health problem at some stage.
- Chronic Fatigue: People with Wolfram syndrome have a progressively declining levels of physical stamina. As this condition progresses they will need increasingly greater amounts of sleep.
Other features of Wolfram Syndrome include fertility problems and gastrointestinal problems causing constipation or diarrhoea.
How is it treated?
There isn’t a cure for Wolfram Syndrome but there are treatments for some of the features. Diabetes mellitus is treated with insulin, and Diabetes insipidus with vasopressin. While hearing aids can help with hearing loss, there is unfortunately no treatment for vision loss. Renal problems may be treated by catheterization (passing a thin, flexible tube into the bladder to drain away urine), and some of the neurological symptoms can be treated with medication.
How common is it?
Wolfram Syndrome is very rare and affects around 1 in 770,000 of the total UK population, or 1 in 500,000 children.
How do you tell if you have Wolfram Syndrome?
There is no test for Wolfram Syndrome but a doctor would diagnose it if a child has both diabetes mellitus and optic atrophy. Because it’s so rare not all doctors will know about it, so if you think you or your child might have it, print off this information and show it to your doctor.
Where can I go for more information?
References: Barrett T.G and Bundey S.E. 1997. Wolfram (DIDMOAD) syndrome. J Med Genet. 34: 838-841; Barrett T.G. 2000.Patient information leaflet http://www.wolframsyndrome.org/PatientLeaflet.htm
The following statements are the expert opinion of Professor Tim Barrett Senior Lecturer/Consultant Paediatrics Department of Endocrinology Birmingham Children's Hospital:
Diabetes mellitus – everyone with Wolfram Syndrome is likely to have diabetes at some point.
Diabetes Insipidus – Half of people with Wolfram syndrome have diabetes insipidus.
Optic atrophy – Everyone with wolfram syndrome will have optic atrophy at some stage.
Neurological problems – About a quarter of people with wolfram syndrome may have mental health problems at some stage.
Chronic Fatigue – Patients with Wolfram syndrome have a progressively declining level of physical stamina. As this condition progresses the Wolfram syndrome patient will require progressively greater amounts of sleep.