Alternative Names
Diabetes mellitus; "sugar"; type I diabetes; type II diabetes
What is Diabetes? Diabetes Symptoms & Complications
Diabetes is a disease in which blood glucose (sugar) levels are too high. Glucose is obtained through diet. Insulin is a hormone that is needed to convert sugar and other foods into energy needed for daily life. When the body does not produce or properly use insulin, sugar cannot be used and gets too high.
Diabetes Types:
There are many different types of diabetes. Major types include:
- Type 1 diabetes results when the body does not produce insulin. Type 1 diabetes is usually diagnosed in non-obese children.
- Type 2 diabetes results when the body is resistant to the effects of insulin and/or the body produces some, but not enough, insulin to maintain normal glucose levels. Type 2 diabetes is usually diagnosed in adulthood and is associated with obesity and lack of exercise.
- MODY (maturity-onset diabetes of the young) results when the body produces less insulin than normal but still has some partial insulin production. MODY is typically diagnosed before 25 years old and is often misdiagnosed as type 1 or type 2 diabetes.
- Neonatal diabetes mellitus can be permanent or transient (goes away) and is characterized by an onset of symptoms within the first six months of life. Some individuals with transient neonatal diabetes mellitus develop type 2 diabetes later in life.
- Gestational diabetes occurs in some pregnant women who did not have diabetes before pregnancy. Gestational diabetes usually resolves after pregnancy but may increase the risk to develop type 2 diabetes later in life.
Signs & Symptoms:
Common signs and symptoms of diabetes include:
- Numbness or tingling in the feet
Complications:
Over time, high blood sugar levels can cause severe damage to eyes, kidneys and nerves; as well as cause heart disease, stroke and even the need to amputate limb(s).
Diabetes Management & Treatment
Treatment and routine monitoring of blood sugar levels can help to manage some of the symptoms and sometimes prevent related problems.
Pregnant women with diabetes, who have been diagnosed before 25 weeks gestation, are at an increased risk to develop pregnancy complications as well as to have a baby with certain birth defects. It is always important to speak with a doctor regarding the appropriate care and management of diabetes before and during pregnancy.
How Common Is Diabetes? Diabetes Statistics
Over 20 million people are believed to be affected with diabetes in the United States.
- About 10% to 15% of people with diabetes have type 1 diabetes.
- Most Americans with diabetes have type 2 diabetes.
- Neonatal diabetes is rare and affects about 1 in 400,000 newborns.
- About 4% of all pregnant women are believed to be affected with gestational diabetes.
What Causes Diabetes? Diabetes Risk Factors & Causes
Type 1 diabetes risk factors:
- Living in a cold climate
- Exposure to certain viruses
- Dietary factors such as low vitamin D levels have been proposed
- Having a family history of diabetes
- A number of genes that influence susceptibility to type 1 diabetes have been identified, but no one gene is strongly associated.
Type 2 diabetes risk factors:
- Being overweight
- Lack of exercise (less than 3 times per week)
- Having a family history of diabetes
- Being of African American, Alaska Native, American Indian, Asian American, Hispanic/Latino, or Pacific Islander ancestry
- Giving birth to a baby weighing more than 9 pounds or being diagnosed with gestational diabetes
- Having high blood pressure
- Having an HDL, or “good,” cholesterol level below 35 mg/dL
- Having a triglyceride level above 250 mg/dL
- Having polycystic ovarian syndrome
- Having heart disease
- A number of genes that influence susceptibility to type 2 diabetes have been identified, but no one gene is strongly associated.
- People who have certain genetic conditions, such as hemochromatosis or mitochondrial conditions, are at an increased risk to develop diabetes.
MODY risk factors:
MODY is a genetic (inherited) disease. There are currently nine identified types of MODY called MODY1-MODY9, which are caused by mutations in nine different genes. MODY2 and MODY3 are the most common forms of MODY in Caucasians.
|
Maturity-Onset Diabetes of the Young (MODY) Genetics
|
| Type |
Gene |
Location* |
| MODY1 |
HNF4A |
20q12-q13.1 |
| MODY2 |
GCK |
7p15.p13 |
| MODY3 |
TCF1 |
12q24.2 |
| MODY4 |
1PF1 |
13q12.1 |
| MODY5 |
TCF2 |
17cen-q21.3 |
| MODY6 |
NEUROD1 |
2q32 |
| MODY7 |
KLF11 |
2p25 |
| MODY8 |
CEL |
9q34 |
| MODY8 |
PAX4 |
7q32 |
| *indicates chromosome number and gene location |
Neonatal diabetes mellitus risk factors:
Transient neonatal diabetes mellitus has been associated with the overexpression of two genes, PLAGL1(ZAC) and HYMAI, found within an imprinted gene region at 6q24, as well as mutations in the KCNJ11 or ABCC8 genes.
Permanent neonatal diabetes mellitus (PNDM) can occur alone (isolated) or as part of a larger genetic syndrome. Isolated PNDM has been associated with mutations in at least five genes. These genes are KCNJ11 (about 30% of cases), ABCC8 (about 19% of cases), INS (about 20% of cases), GCK (about 4% of cases), and PDX1 (<1% of cases). Syndromic cases are caused by mutations in different genes.
- About 20% of people with mutations in the KCNJ11 gene have associated neurological features called DEND syndrome (developmental delay, epilepsy, and neonatal diabetes mellitus). Intermediate DEND syndrome refers to a milder form of the condition without seizures and with less severe developmental delay.
Gestational diabetes risk factors:
- Being overweight
- Having a family history of diabetes
- Being of African American, Alaska Native, American Indian, Hispanic/Latino, or Pacific Islander ancestry
- Giving birth to a baby weighing more than 9 pounds or being previously diagnosed with gestational diabetes
- Being older than 25 years old
Diabetes Inheritance & Family History
Type 1 and type 2 diabetes have multifactorial inheritance, which means genetic, lifestyle and environment factors contribute to the development of the disease.
- Children of men with type 1 diabetes have a 1 in 17 risk of developing the disease. Children of women with type 1 diabetes have a 1 in 25 to 1 in 100 risk of developing the disease (depending on if they were born before or after their mother was age 25).
- Children of people with type 2 diabetes have an approximate 1 in 10 risk of developing diabetes. Some researchers believe that a child's risk is greater when the parent with type 2 diabetes is the mother.
- People who have multiple, close family members who are affected with either type 1 or type 2 diabetes have an even higher risk of developing these diseases.
MODY has autosomal dominant inheritance, which means having a mutation in a single gene copy is sufficient enough to cause the disease. An affected person has a 50% chance with each pregnancy to have an affected child
Neonatal diabetes has autosomal dominant inheritance or autosomal recessive inheritance depending on the type and gene involved.
- While some cases of autosomal dominant cases are inherited from an affected parent, most cases occur due to a new, sporadic ("de novo") mutation in people with no family history of the disorder. Affected people have a 50% chance to have an affected child with each pregnancy.
- Both parents of an person with autosomal recessive cases are obligate carriers (each have only one mutation). Two carriers have a 25% chance with each pregnancy to have an affected child, but typically do not have symptoms themselves; however, carriers for mutations in GCK may have MODY2.
Diabetes Tests & Diagnosis
The following clinical tests are used in the diagnosis of diabetes:
- A fasting plasma glucose (FPG) test measures blood sugar in a person who has fasted for at least 8 hours.
- An oral glucose tolerance test (OGTT) measures blood sugar after a person fasts at least 8 hours and 2 hours after the person drinks a glucose-containing beverage.
- A random (casual) plasma glucose test measures blood sugar without regard to when the person being tested last ate.
- A glycated hemoglobin (A1C) test measures the average blood sugar level for the past two to three months.
Clinical genetic testing for mutations that cause MODY and neonatal diabetes are available for people who are considered at risk.
Diabetes Prevention & Related Issues
Currently, there are no known ways to prevent type 1 diabetes, MODY, or neonatal diabetes. In some women, gestational diabetes cannot be prevented; however, maintaining a healthy weight before and during pregnancy and regular exercise may help lower the risk.
It is never too early to prevent type 2 diabetes. Some ways to lower disease risk include:
- Maintain a healthy weight
- Eat a diet low in fat and cholesterol
- Exercise regularly (more than 3 times per week)
- Control blood pressure and cholesterol levels
Diabetes Support & More Information
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