Diabetes mellitus, also known as diabetes, is caused by an inability of the body to correctly produce, or use, insulin. There are two main types of diabetes: Type 1 diabetes, sometimes known as insulin dependent diabetes, accounts for up to 10 percent of cases and occurs when the insulin-producing cells in the pancreas are attacked by the body's immune system. Most patients with diabetes -- approximately 90 to 95 percent -- have type 2 diabetes, which is caused by a resistance to the insulin produced by the pancreas. However, there are other, more rare forms of this disease.
Maturity Onset Diabetes of the Young
Maturity onset diabetes of the young, or MODY, is caused by genetic defects in the beta cells, which produce insulin within the pancreas gland. This type of diabetes is called monogenic diabetes because a change in one gene can cause the disease. Patients with MODY have inherited a mutated, or changed, gene from one of their parents; this mutated gene results in abnormal insulin production by the pancreas. As explained by the National Diabetes Information Clearinghouse website, MODY may not cause any symptoms and may be found when a blood test done during a routine exam shows abnormally high levels of blood sugar. Treatment of MODY may not require insulin injections; patients may be able to control their high sugar levels with medications taken by mouth. Because this is a genetic disease, patients will often have a strong family history of diabetes -- a parent and a grandparent may have diabetes. Patients with this condition may want to consider meeting with a genetic counselor as this health care professional can help guide discussions about whether testing is appropriate, who in the family may need to be tested, and what should be done about positive test results.
Neonatal Diabetes Mellitus
Another rare form of diabetes is called neonatal diabetes mellitus, or NDM. This is also a monogenic disease, meaning that a mutation in a single gene has resulted in the disease; this is in contrast to the more common type 1 and type 2 diabetes that involve mutations to several different genes. According to the National Diabetes Information Clearinghouse, NDM is an extremely rare form of diabetes, being diagnosed in only 1 out of every 100,000 to 500,000 live births. Babies with NDM will have symptoms of thirst, frequent wet diapers, indicating frequent urination, and dehydration, which occurs as the levels of blood sugar increase to dangerously high levels. Interestingly, NDM is often misdiagnosed as type 1 diabetes; however, patients with type 1 usually do not show symptoms before age 6 months. About half of those babies diagnosed with NDM will have this condition permanently, while the other half will have it temporarily, in which case the condition is called transient NDM. The University of Washington-affiliated website called GeneReviews, in its discussion of NDM reports that treatment for NDM is somewhat dependent on which type of gene mutation caused the disease; patients with two specific gene mutations may be treated with oral medications, while patients with any of the other mutations known to cause NDM must be treated with insulin injections.
Leprechaunism
The Dermatology Information System website describes leprechaunism as a very rare disorder in children that appears to be inherited. Besides unusual physical characteristics, it is associated with an inability of the body to use the insulin that is produced by the pancreas; this is called insulin resistance. In extreme cases of insulin resistance, diabetes develops. The National Diabetes Information Clearinghouse lists several symptoms suggesting that significant, disease-causing insulin resistance have developed including acanthosis nigricans, which are dark, velvety patches of skin in body folds such as the neck, as well as masculinization in women, presenting with such symptoms as abnormal facial hair growth.
References
- National Diabetes Information Clearinghouse: What is maturity-onset diabetes of the young (MODY)?
- National Diabetes Information Clearinghouse: Diabetes Overview
- University of Washington-Seattle Gene Reviews: Permanent Neonatal Diabetes Mellitus
- National Diabetes Information Clearinghouse: What is Neonatal Diabetes Mellitus (NDM)?
- MayoClinic.com: Acanthosis Nigricans
- Dermatology Information System: Leprechaunism Syndrome
