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Disease Profile

Brittle diabetes

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.


US Estimated

Europe Estimated

Age of onset





Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)

Labile diabetes; Brittle diabetes mellitus; Brittle type 1 diabetes


Brittle diabetes is a term that is sometimes used to describe hard-to-control diabetes (also called labile diabetes). It is characterized by wide variations or “swings” in blood glucose (sugar) in which blood glucose levels can quickly move from too high (hyperglycemia) to too low (hypoglycemia). These episodes are hard to predict and can disrupt quality of life. They can require frequent or lengthy hospitalizations and can be fatal.

People with type 1 diabetes are at greatest risk. While many people with type 1 diabetes experience hypoglycemia, only a small proportion of people with type 1 diabetes experience the frequent blood glucose swings described as “brittle.” People with long-standing type 2 diabetes may also have difficulty controlling blood glucose, but few have these frequent swings. People of any age with diabetes can be affected with these frequent ups and downs in blood glucose levels. Some research suggests that women may be affected more often than men.

Frequent episodes of hypoglycemia can lead to hypoglycemic unawareness and make the condition worse. Keeping diabetes under good control for at least several weeks can restore hypoglycemic awareness. New technologies such as continuous glucose monitors and insulin pumps may help improve control.

In diabetes, many factors can trigger frequent changes in blood glucose levels. For example, people who don’t test blood glucose or take diabetes medications as prescribed often experience significant fluctuations in blood glucose levels. Other causes of unstable blood glucose levels include emotional stress, eating disorders, drug or alcohol use, malabsorption, gastroparesis, and celiac disease.  

The development of new treatments for diabetes has made it easier for most people to control their blood glucose levels. Artificial pancreas technology is currently being tested in clinical trials and aims to help people with type 1 diabetes more easily manage blood glucose levels. In 2016, the U.S. Food and Drug Administration approved a hybrid model of an artificial pancreas, an automated system that requires users to adjust insulin intake at mealtimes. NIH-funded research on islet cell transplantation has also shown promising results in restoring blood glucose control. This research specifically includes people who have experienced episodes of severe hypoglycemia.

Learn more

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

In-Depth Information

  • PubMed is a searchable database of medical literature and lists journal articles that discuss brittle diabetes. Click on the link to view a sample search on this topic.


  1. McCulloch DK. The adult patient with brittle diabetes mellitus. UpToDate. June 5, 2015; https://www.uptodate.com/contents/the-adult-patient-with-brittle-diabetes-mellitus?detectedLanguage=en&source=search_result&search=brittle+diabetes&selectedTitle=1%7E6&provider=noProvider.
  2. Standards of Medical Care in Diabetes-2017. Diabetes Care. 2017; 40(Suppl. 1):https://professional.diabetes.org/sites/professional.diabetes.org/files/media/dc_40_s1_final.pdf.
  3. Islet transplantation restores blood sugar awareness and control in type 1 diabetes. NIH News Release. April 18, 2016; https://www.nih.gov/news-events/news-releases/islet-transplantation-restores-blood-sugar-awareness-control-type-1-diabetes.