What is Monogenic Diabetes?
Type 1 diabetes and type 2 diabetes are called "polygenic" because they are the result of defects or changes in multiple genes. There are also types of diabetes called "monogenic," which means they are the result of a mutation in one, single gene.
There are two main types of monogenic diabetes:
Neonatal Diabetes Mellitus (NDM) - This is a rare condition that occurs in the first 6 - 12 months of life, accounting for up to 1 in 400,000 infants in the United States.1 According to the NIDDK, "infants with NDM do not produce enough insulin, leading to an increase in blood glucose. NDM is often mistaken for type 1 diabetes, but type 1 diabetes is very rarely seen before 6 months of age. Diabetes that occurs in the first 6 months of life almost always has a genetic cause. Researchers have identified a number of specific genes and mutations that can cause NDM. In about half of those with NDM, the condition is lifelong and is called permanent neonatal diabetes mellitus (PNDM). In the rest of those with NDM, the condition is transient, or temporary, and disappears during infancy but can reappear later in life. This type of NDM is called transient neonatal diabetes mellitus (TNDM)."
Maturity Onset Diabetes of the Young (MODY) - This monogenic form of diabetes usually first appears during the teen years or young adulthood. Several different gene mutations can cause MODY, which ultimately limits the pancreas's ability to make insulin.
Should I get tested for monogenic diabetes?
A combination of tests and clinical factors help doctors rule out type 1 or type 2 diabetes:
- Monogenic diabetes is passed on in a sex-independent gene from one of the parents (autosomal dominant gene), and there is often a strong family history of diabetes across multiple generations. Diagnosis would require genetic testing.
- Monogenic diabetes presents most often as antibody-negative (unlike type 1 diabetes, which presents with antibodies).
- Certain clinical factors suggest monogenic diabetes, such as: being diagnosed within the first six months of life, not being obese, a family history of diabetes (especially a parent), and the presence of other gene mutation conditions (ex. kidney cysts)
- More information about the genes that cause NDM and MODY, the types of mutations responsible for the disease (autosomal dominant, autosomal recessive, X-linked, etc.), and clinical features is provided in the American Diabetes Association Standards of Medical Care in Diabetes.
- Monogenic Diabetes, from the Hormone Health Network
- Monogenic Diabetes, Not Your "Typical Diabetes."
- Other Types of Diabetes from the Diabetes UK
- Statistic from "What is neonatal diabetes mellitus (NDM)?" on the NIDDK website