Diabetes causes are numerous and range from genetic problems to diseases of the pancreas. More on what causes diabetes.
The Different Causes of Diabetes
Diabetes Caused by Genetic Defects of the Beta Cell
Genetic defects of the beta cell cause several forms of diabetes. For example, monogenic (one pair of genes) forms of diabetes result from mutations, or changes, in a single gene. In most cases of monogenic diabetes, the gene mutation is inherited. In the remaining cases, the gene mutation develops spontaneously. Most mutations in monogenic diabetes reduce the body's ability to produce insulin. Genetic testing can diagnose most forms of monogenic diabetes.
NDM and MODY are the two main forms of monogenic diabetes. NDM is a form of diabetes that occurs in the first 6 months of life. Infants with NDM do not produce enough insulin, leading to an increase in blood glucose. NDM can be mistaken for the much more common type 1 diabetes, but type 1 diabetes usually occurs after the first 6 months of life.
MODY usually first occurs during adolescence or early adulthood. However, MODY sometimes remains undiagnosed until later in life. A number of different gene mutations have been shown to cause MODY, all of which limit the pancreas' ability to produce insulin. This process leads to the high blood glucose levels characteristic of diabetes. More information about specific types of MODY is provided in the fact sheet Monogenic Forms of Diabetes.
Diabetes Caused by Genetic Defects in Insulin Action
A number of types of diabetes result from genetic defects in insulin action. Changes to the insulin receptor may cause mild hyperglycemia—high blood glucose—or severe diabetes. Symptoms may include acanthosis nigricans, a skin condition characterized by darkened skin patches, and, in women, enlarged and cystic ovaries plus virilization and the development of masculine characteristics such as excess facial hair. Two syndromes in children, leprechaunism and the Rabson-Mendenhall syndrome, cause extreme insulin resistance.
Diabetes Caused by Diseases of the Pancreas
Injuries to the pancreas from trauma or disease can cause diabetes. This category includes pancreatitis, infection, and cancer of the pancreas. Cystic fibrosis and hemochromatosis can also damage the pancreas enough to cause diabetes.
Diabetes Caused by Endocrinopathies
Excess amounts of certain hormones that work against the action of insulin can cause diabetes. These hormones and their related conditions include growth hormone in acromegaly, cortisol in Cushing's syndrome, glucagon in glucagonoma, and epinephrine in pheochromocytoma.
Diabetes Caused by Medications or Chemicals
A number of medications and chemicals can interfere with insulin secretion, leading to diabetes in people with insulin resistance. These medications and chemicals include pentamidine, nicotinic acid, glucocorticoids, thyroid hormone, phenytoin (Dilantin), and Vacor, a rat poison.
Diabetes Caused by Infections
Several infections are associated with the occurrence of diabetes, including congenital rubella, coxsackievirus B, cytomegalovirus, adenovirus, and mumps.
Rare Immune-mediated Types of Diabetes
Some immune-mediated disorders are associated with diabetes. About one-third of people with stiff-man syndrome develop diabetes. In other autoimmune diseases, such as systemic lupus erythematosus, patients may have anti-insulin receptor antibodies that cause diabetes by interfering with the binding of insulin to body tissues.
Other Genetic Syndromes Sometimes Associated with Diabetes
Many genetic syndromes are associated with diabetes. These conditions include Down syndrome, Klinefelter's syndrome, Huntington's chorea, porphyria, Prader-Willi syndrome, and diabetes insipidus.
Last Updated: 09 March 2016
Reviewed by Harry Croft, MD