Types of Diabetes

It's world diabetes day today and I have noticed that while most people are aware of type 1 and 2 diabetes and possibly gestational diabetes many of the other types are not known by many. Here's a quick overview of some.

I'm not going to go into diabetes insipidis, as that's a different group of conditions, these all refer to types of diabetes mellitus . With diabetes mellitus, either not enough insulin is being produced, or the body isn't responding well to normal levels of insulin (or both).

Type 1 Diabetes - I think when young this is the form of diabetes many first hear about unless there's a relationship to someone with another type. Enough insulin is not produced and it is often due to an autoimmune disease where antibodies attack the beta cells of the pancreas. Multiple genes can lead one to being at risk of developing this condition. People with this condition are insulin-dependent. Age of onset is often during childhood or adolescence, and this type was commonly referred to as juvenile diabetes although that terminology is a bit outdated.

Type 2 Diabetes - This is the most common type of diabetes, and with this type the body is insensitive to normal levels of insulin. Multiple genes as well as lifestyle factors can increase the risk of developing this form of diabetes. Diet and exercise can allow this type of diabetes to be fairly controlled and not all will need insulin, although for some it is required.

LADA - This stands for Latant Autoimmune Diabetes in Adults and has also been referred to as Type 1.5. This only occurs in adults and is very similar to type 1 diabetes, although due to the age of onset it is sometimes separated from type 1 diabetes, although some combine it together. Often times people with this diabetes are misdiagnosed with type 2 diabetes and it can delay getting the appropriate treatment with insulin. Lifestyle changes and some medications besides insulin can be used to treat this form for a period of time as it does often develop slower than type 1 diabetes in children, but typically it progresses to one becomes insulin dependent. Lifestyle factors and multiple genes can increase the risk of developing LADA. Increased recognition of this particular form of diabetes is improving initial correct diagnoses, as there are tests that can distinguish this from type 2 diabetes.

Gestational Diabetes - This type occurs in those who are pregnant. It is similar to type 2 diabetes and is also due to an insulin insensitivity. It often resolves once the person is no longer pregnant, but those who have had it are at higher risk for type 2 diabetes and for some the condition doesn't even resolve at the end of their pregnancy, although it is usually at least less severe.

MODY - Maturity onset diabetes of the young. This is actually a group of different types of diabetes, and while symptoms are not apparent in babies, it appears before the age of 25. These are caused by one gene and typically are autosomal dominant conditions, so someone with the gene has a 50% chance of passing it on to biological children without intervention. Due to the age of onset, a misdiagnosis of type 1 diabetes is fairly common. In many cases though those who have one of these conditions are not insulin dependent and there are currently medications for some of these conditions that work quite well but would not be suitable for type 1 diabetes.

Some of the known mutations that result in MODY occur in the genes encoding the following proteins: HNF4-alpha, HNF1-alpha, HNF1-beta, glucokinase, insulin, insulin promoter factor-1, Pax4, Tyrosine-protein kinase BLK, neurogenic differentiation 1, Kruppel-like factor 11, Bile salt dependent lipase. This hopefully gives an idea of the diversity that occurs within this group, and it's possible there are others that have been yet to be discovered.

Some specific MODY conditions are also associated with other health issues such as gout, which is another reason why a proper diagnosis can be important to one's health.

Neonatal - Like MODY, this is also often due to a single gene but the inheritance patterns are not necessarily autosomal dominant and the age of onset occurs during infancy. Neonatal diabetes can be split into 2 types, permanent and transient. With transient neonatal diabetes, the condition resolves around 12 weeks, but it relapses about 50% of the time and puberty or pregnancy are frequent periods for the relapse. Mutations within the insulin gene or that are responsible for converting preproinsulin into insulin are some of the causes of neonatal diabetes, but like MODY there are multiple genes that are known causes. Not all are currently known; genetic testing results in a specific diagnosis 82% of the time (https://www.diabetesgenes.org/about-neonatal-diabetes/)

Wolfram Syndrome - also known as DIDMOAD (Diabetes Insipidus, Diabetes Mellitus, Optic Atrophy and Deafness) As the name suggests, diabetes mellitus is just one part of this condition. The diabetes aspect presents similarly to type 1 diabetes and is typically present by the age of 6, and is one of the first signs of this syndrome. There are 2 different genes that are known to cause this syndrome - WFS1 (the wolframin gene) and CISD2. Those caused by the latter due not develop diabetes insipidus, but do get ulcers and heavy bleeding after an injury to the gastrointestinal tract.

Diabetes can also be associated with other health conditions, where diabetes isn't necessarily the primary sign. These include Alstrom-syndrome, Cystic Fibrosis, Cushing's Syndrome, and Chronic Pancreatits.

References:

https://beyondtype1.org/

https://en.wikipedia.org/wiki/Maturity_onset_diabetes_of_the_young

https://en.wikipedia.org/wiki/Neonatal_diabetes_mellitus

https://www.diabetesgenes.org/

https://www.diabetes.org.uk/