OTHER SPECIFIC TYPES OF DIABETES

MODY (MATURITY ONSET DIABETES OF YOUNG)

Diabetes due to genetic defects in the beta-cell are referred to as MODY and are characterized by impaired insulin secretion with minimal or no defects in insulin action. MODY is a monogenic condition caused by a mutation of a single gene that is inherited as an autosomal dominant trait. The onset of diabetes usually occurs in childhood or adolescence, usually before 25 years of age. It may be mistaken for type 2 diabetes because management of both conditions does not require insulin, at least in the early stages of the diseases. However, many differences exist between MODY and Type 2 Diabetes.   They are follows:

  • Hyperglycemia in MODY is mild in some cases and may be missed, as with type 2 diabetes.
  • MODY may be misdiagnosed as type 1 diabetes when hyperglycemia is detected in children.
  • Children or adolescents with MODY are not usually overweight whereas those with type 2 diabetes are usually overweight.

DISEASES OF THE EXOCRINE PANCREAS

Any conditions that injure the pancreas diffusely can result in diabetes. These conditions imply that a mechanism other than reduction in beta-cell mass may also be responsible for diabetes.

DRUG OR CHEMICAL INDUCED DIABETES

Insulin secretion can be impaired by many drugs.  These drugs may not cause diabetes by themselves, but they precipitate diabetes in individuals with pre-assisting insulin resistance and deficiency.  In addition, certain hormones, when in excess or when given in a therapy can impair the action of insulin.  In rare cases, particular toxins and specific drugs can permanently destroy the beta cells of pancreas.

GESTATIONAL DIABETES MELLITUS  

Gestational Diabetes occurs during pregnancy, usually starting between 20-28 weeks of Gestation and usually resolves after delivery of the baby.  Women, who have diabetes before pregnancy as said to have pregnancy complicated by Diabetes.   Gestational Diabetes is similar to Type 2 Diabetes, in that there is both Insulin Resistance and an insuffiency of Insulin secretion.

Diagnostic Testing Criteria for GDM

 75 gm two hour GTT ADA WHO
0 hour > 92 > 125
1 hour > 180 OR
2 hour > 153 > 140

 

LATENT AUTOIMMUNE DIABETES OF ADULT (LADA)

 

LADA is the most common term describing patients with a type 2 diabetic phenotype combined with islet antibodies and slowly progressive β-cell failure. If defined as a type 2 diabetic phenotype combined with islet antibodies, the prevalence of LADA is around 10% among incident case subjects of diabetes aged 40–75 years.   People with LADA have a slowly progressing form of type 1 diabetes. This means they do not need insulin when they are diagnosed but will probably need insulin in the future.  How soon they will be insulin dependent depends on the level of antibody they have in their blood. Higher levels of antibodies suggest a faster progression to insulin. People with low levels of antibodies are very similar to type 2 diabetes patients. This means they are more likely to be overweight and have some insulin resistance. They are likely to benefit from tablets that act on insulin resistance. People with very high antibody levels are similar to type 1 diabetes. This means they are likely to have acute symptoms (thirst, unexplained weight loss, frequent urination, dry mouth) and are less likely to be overweight.  They are likely to need insulin treatment soon after diagnosis. Key characteristics of type 1, LADA (latent autoimmune diabetes in adults), and type 2 are as follow in the table below;

 

 

Diabetes Types 

 

Type 1

 

LADA

 

Type 2

 

Typical age of onset

 

Youth or adult

 

Adult

 

Adult

 

Progression to insulin dependence

 

Rapid (days/weeks)

 

Latent (months/years)

 

Slow (years)

 

Presence of auto antibodies*

 

Yes

 

Yes

 

No

 

Insulin dependence

 

At diagnosis

 

Within 6 years

 

Over time, if at all

 

Insulin resistance

 

No

 

Some

 

Yes

 

* Proteins that indicate the body has launched an autoimmune attack on the insulin-producing beta cells in the pancreas.