Maturity-onset diabetes of the young (MODY) is a group of several medical conditions characterized by unusually high sugar levels. High sugar levels (hyperglycemia) can cause damage to your nerves and organs, so treatment is usually needed.
Understanding the different types of MODY, possible side effects and complications, and the treatment options available will help you get the right diagnosis and effectively manage your condition.
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MODY is a monogenic form of diabetes. This condition and other monogenic forms of diabetes (such as neonatal diabetes mellitus) are caused by a change in one gene. In contrast, type 1 and type 2 diabetes (the most common forms of the condition) are caused by a change or defect in multiple genes.
Monogenic forms of diabetes make up 1–4%¹ of all diabetes cases in the US, while MODY accounts for 1%.²
MODY is often defined by the following key features:
You have two consecutive generations with diabetes in your family
You might not need insulin
You are diagnosed under the age of 25
MODY diabetes may be confused with type 1 and type 2 diabetes, and misdiagnoses often occur.
There are currently 14 different conditions recognized as types of MODY diabetes.
Common types of MODY include:
HNF1-alpha causes diabetes by lowering the level of insulin produced by the pancreas.
The gene is responsible for about 30 to 60%³ of all MODY cases, and the condition often starts to grow more evident in teenagers or people in their early 20s.
You may not need insulin with HNF1-alpha, but your doctor may recommend taking a small dose of a group of tablets called sulphonylureas. Sulphonylureas are typically used to treat type 2 diabetes and work by helping the pancreas produce more insulin.
With HNF1-beta, you may be more susceptible to several health conditions, including gout, uterine abnormalities, and renal cysts. This type of MODY is sometimes called renal cysts and diabetes syndrome (RCAD).
Diabetes usually develops later in life with this type of MODY. You may need insulin treatment, complemented by a healthy, balanced diet and regular physical activity.
This gene can reduce the amount of insulin produced by the pancreas, causing diabetes.
HNF4-alpha MODY typically occurs in childhood or early adulthood, but it can also be diagnosed in older people.
With HNF4-alpha, you may have had a high birth weight (9lb or 4kg) and/or low blood sugar when you were born (or shortly after).
HNF4-alpha can be treated with sulphonylurea tablets, but you may need insulin later in life as your pancreas produces less insulin.
The glucokinase gene helps your body recognize blood glucose levels. Mutated, the gene allows your body to have higher glucose levels than expected.
GCK gene mutation affects 0.1%⁴ of the population and 0.4 to 1% of women with gestational diabetes mellitus.
Although you may have the condition from birth, there are no symptoms. Your doctor may detect GCK-MODY through routine glucose testing or during pregnancy.
Most monogenic diabetes cases occur when a child inherits the gene mutation from one or both parents. Humans have approximately 25,000 genes, and scientists have linked 20 to monogenic diabetes⁵ so far.
With MODY, a child has a 50%⁶ chance of inheriting the gene mutation if their parents have it and will likely go on to develop the condition before the age of 25, regardless of environmental factors.
MODY is not always inherited. Some cases are caused by a gene mutation, where the person has no family history of MODY.
MODY is inherited, meaning the condition runs in families. If one of your parents has an affected gene, you have a 50% chance of developing MODY.
The condition is most likely to develop between the ages of 10 and 40.⁷ Unlike type 2 diabetes, people with MODY are typically healthy, and there is no link to high blood pressure or obesity.
MODY signs and symptoms are generally the same as other kinds of diabetes. This is why the condition is so often missed or misdiagnosed as type 1 or type 2 diabetes.
Common signs and symptoms of MODY include:
Recurrent yeast infections
Recurrent skin infections
Note that GCK-MODY does not typically cause symptoms.
All types of MODY, apart from GCK-MODY, carry the risk of long-term diabetes complications. Knowing your specific MODY type will allow your doctor to test for other related conditions.
Possible complications associated with MODY diabetes include:
Nerve damage in your extremities (neuropathy)
Diabetic kidney disease (nephropathy) — may cause kidney failure
Diabetic eye disease (retinopathy) — may cause vision problems
Cardiovascular disease — may cause narrowing of the arteries, heart attack, and stroke
A MODY diabetes diagnosis test is important because not all forms of MODY diabetes have visible symptoms. A proper diagnosis will enable your doctor to recommend the most suitable treatment strategy for you.
Bear in mind that not all types of MODY diabetes require insulin or oral medication.
A blood sugar test is the first step toward diagnosing MODY diabetes. Depending on the results, your doctor may recommend a genetic test to determine your specific MODY diabetes type.
MODY is caused by a hereditary mutation, so there is no cure for the condition. However, an accurate diagnosis can put you on track to managing MODY.
Your doctor will recommend a treatment plan depending on the type of MODY you have. Treatment may include oral medications or insulin injections.
Some types of MODY may not require any treatment. Glucokinase (GCK-MODY), for example, causes mild symptoms that stabilize without any treatment.
MODY characterized by low insulin levels is treated with oral diabetic medication, which works by helping the body release insulin, establishing a temporary balance.
Since MODY diabetes is hereditary, it’s important to consider genetic testing as there is a 50% chance of a parent passing on the gene.
MODY diabetes is rare and can often go undetected or be misdiagnosed. Untreated, MODY can damage your body tissues, nerves, and organs, causing complications like vision problems, kidney failure, or stroke.
You may experience symptoms of MODY, including increased thirst, fatigue, and recurrent yeast infections (in women). However, not all types of MODY produce symptoms and may only be identified through routine testing.
Speak to your doctor if you’re concerned about diabetes. They can order tests to establish the cause of your symptoms if you have any and recommend a suitable treatment program. Early diagnosis and treatment can help you manage the condition effectively.
Monogenic diabetes (Neonatal diabetes mellitus & MODY) | National Institute of Health
MODY | The University of Chicago Kovler Diabetes Center
Maturity onset diabetes in the young | StatPearls
What is monogenic diabetes? | The University of Chicago Kovler Diabetes Center
Maturity onset diabetes of the young (mody) | Diabetes UK
Maturity onset diabetes in the young | StatPearls
What is maturity-onset diabetes of the young? | Diabetes Genes
MODY diabetes: Everything you need to know | Diabetes Strong