Getting Type 1 diabetes is seen by many people
as a complete disaster. Effective treatment has been around for less than a
hundred years and before that life expectancy after diagnosis was very short,
with most patients dying before they had reproduced.
Although there are environmental
triggers, the existence of diabetes is largely determined by a number of genes.
How is it that these genes persist in a population over generations if many of
the carriers of those genes do not reproduce?
We can infer an answer to this question
by looking at single gene diseases in which the situation is clearer. For
example thalassaemia, sickle cell disease, G6PD and other red cell disorders
gave heterozygotes some resistance to the effects of malaria, the cystic
fibrosis gene protected against cholera and the gene for haemochromatosis was
useful in dealing with anaemia due to hookworm and other causes.
So these serious diseases persist
because their effects were not all bad.
(Aside: I am aware of research showing
how a gene with effects that are all deleterious at a young age can persist in
a population, but I think this mechanism does not apply to diabetes. Genetic
diseases that kill the elderly do not impede the survival of the gene. In fact
they may enhance it)
Why do Type 1 diabetic genes persist in
the population. The answer has to be that some of these genes confer a survival
advantage. What advantage? I don’t know but there must be one. It may be that
diabetic genes improve performance to a small degree in a broad range of activities
and a specific advantage will never be determined. ( the evidence in favour of this will be in a later post)
I used to think about what life would be
like if I didn’t have diabetes. I wouldn’t have the hassle, but on the other
hand I wouldn’t have the advantages. Maybe my skiing abilities would be much
worse.
So don’t hate your diabetes. Learn to
deal with the downsides, so that the good effects can shine through.
