DIABETES:  Is it Hereditary?

Diabetes Mellitus is considered worldwide to be one of the most notorious diseases of the adrenal glands.  It  raises the blood sugar levels as a result of the decrease in insulin hormone or its non efficacy.  This in turn has its damaging effect on different systems of the body particularly the blood vessels whether in the eyes, the kidneys or the nervous system.

In the USA there are 10 million diabetics and this rate doubles every 15 years.

Statistics have proven that 1.9/1000 children and 2-5% adults are diabetic.  It has been noted that children and young people in Japan and Sri Lanka are rarely inflicted.

1- The Symptoms and complications of Diabetes Mellitus:

The first diagnosis of the disease may be a case of coma resulting from increased sugar level in the blood and acetone in the blood or urine.  This may also become noted in case of dizziness or vomiting or hyperventilation.

Diabetics are 25 more times susceptible to loss of eye sight, 17 more times to kidney diseases and 5 more times to gangrene infection which may lead to amputation of the afflicted organ.  In addition,  diabetics are twice as prone to other complications such as heart disease and  brain tumors as normal persons.

Diabetes causes death to 30,000 persons in the USA each year, and is considered the seventh cause of infant deaths.

2- Types of Diabetes Mellitus:

a- Type I Insulin Dependant Diabetes Mellitus

      This usually attacks younger persons (Juvenile Diabetes).  It is caused by decrease in insulin hormone, therefore the only treatment for it is Insulin injections. It may also attack 15-20% of adults above age 40 and is extremely dangerous and may cause death.

b- Type II Non Insulin Dependant Diabetes Mellitus

This type attacks older persons and only 5% of persons under 30 (Maturity Onset Diabetes Mellitus).  It is caused by obesity, non-efficacy of insulin hormone due to antibodies or as a result of  anti-insulin hormones.

c- Secondary Diabetes Mellitus

      This is a  result of the use of cortisone tablets in large dosages for extended periods, or contraceptive pills, diuretics or as a result of chronic pancreatic infection or increased secretion of anti-insulin hormone in certain diseases such as Acromegaly and Pheochromocytoma.

d- Gestational Diabetes

1-3% of  women are afflicted during the first three months of pregnancy.  In most cases this is a transient state caused by decrease  in sugar flow allowed to the urine by the kidneys due to hormonal changes during pregnancy.  This may cause delivery of a large, heavy baby, prone to problems of the respiratory system and reduced sugar levels.

3-  Role of the lab in diagnosis and follow-up:

If diagnosis of diabetes is confirmed,  then a long journey of continuous lab tests begins, in order to ensure control of the disease, since its complications  are dangerous not only due to the length of the disease but more importantly the loss of control over blood sugar levels.
           
1. Measuring Blood Glucose 
    
a- Blood glucose is measured while the patient has been fasting between 6   and 8 hours or after eating.  This means that a sample is taken 2 hours after the start of a meal.  Diagnosis is confirmed  if the fasting sugar level  or the sugar level 2 hours after eating  exceeds 126 mg.% for two consecutive times.

 b-In certain cases, diagnosis is not confirmed except after doing a      complete glucose curve. This means that the first  sample is taken while the patient is fasting, then he/she drinks a glucose fluid then  samples are taken after half an hour, then one hour then 2 then 3 hours thereafter.

Usually, children  do not need a complete glucose curve to determine if they are diabetic, contrary to adults, particularly in suspicious cases such as persons who were afflicted once whether due to pregnancy, stress (Stress Diabetes) or any other bodily infection.  It is recommended that susceptible persons such as twin to a diabetic parent  do a complete sugar curve.

2. Measuring Glucose in Urine  

This is for quick screening and cannot be relied upon for diagnosis, follow-up or treatment.
      
Glucose level may be high in the blood but does not show in the urine because the level is lower than that allowed to flow to the urine through the kidney.

Glucose may be present in the urine in other diseases and may not be accompanied by raised blood sugar levels such as in cases of dysfunctional digestive system (Alimentary Glucosuria) or kidneys (Renal Glucosaria) and pregnancy (Pregnancy Glucosaria).

3-     Glycosylated Hemoglobin

This test is done regularly each 3 months to ensure control of blood glucose levels during the previous 3 months and consequently throughout the year.
This represents that part of the hemoglobin to which glucose gets  attached inside the red blood cells.  It's rate in normal persons is between 6-8%.

4- Fructosamine

This test is performed monthly to give an indication of the control  of glucose levels in the blood.

5- Measuring the Insulin Hormone

This hormone must be measured coincidently with blood glucose levels.
The downside of this test is that it does not differentiate between insulin secreted internally by the pancreas and external insulin if the patient is being treated by it. 

The most important use of this test is to diagnose failed response to diabetes treatment by tablets and in this case, it is usually found that insulin levels are low.

6-      C-Peptide

                  This hormone secretes an amount of insulin equal to that secreted by the pancreas without being influenced by external insulin or inactive insulin present in the body.  Therefore, it is a good indicator of the function of the Beta cells which secrete insulin.  75% of diabetic children pass through a phase called Honeymoon Period for its recurrent  decreased blood glucose which necessitates gradual reduction in insulin.  This phase may last for several weeks or months upto two years.  In this case,  C-Peptide is considered a very accurate test of the insulin secreting cells.

7-   Insulin Antibodies

This test is useful in the diagnosis of patients who do secrete insulin, but their bodies also secrete antibodies which block the effects of insulin.  This is caused by   the use of  animal derived insulin because of its low price.

8- Microalbuminaria

This is considered the most accurate method for early detection of kidney dysfunction as a result of diabetes or hypertension.

2- Is Diabetes Hereditary?

Diabetes is not hereditary. However, what is hereditary is the easy susceptibility to the disease as a result of numerous factors such as tendency for obesity, hypertension, continuous stress etc.
- In the case of Insulin Dependent Diabetes Mellitus, the chances of
having it are 1.7% if the mother is afflicted and 4.7% in case of     the father.   In case both are diabetic, then the chances increase to 23%.   Additionally, it has been noted the rate increases even further in case of  Mongoloidism.

- In the case of Non Insulin Dependent Diabetes Mellitus the rate increases 8-fold in 70% of  obese patients and it may reach 100% in the case of identical twins.

The importance of knowing  the basis of heredity and its percentages in    Diabetes Mellitus is that the above persons are considered High Risk and must therefore be checked periodically to diagnose the disease at its early stages and prevent complications.
 
LABORATORY TESTS

Monthly Tests: Blood Glucose + Fructosamine

Trimestrial Tests: Glycosylated + Hemoglobin + Microalbuminuria

Annual Tests: General Check-up

Specialized Tests: Insulin, Insulin antibodies, C-Peptide