Tuesday, 18 March 2014

Type 2: Genetic Reliance

Disclaimer: This contains science related subject matter from various sources, however (despite studying bachelors in biology) I am not a doctor or an expert in this area. The evidence for this has been obtained from reliable sources.
When someone finds out that I'm diabetic the first question they ask is: 'Type 1 or Type 2?' with my response being type 1. Following this they often attempt to console me with comments like 'oh right so it wasn't your fault' or 'so you inherited it?'. Sometimes I can feel quite offended when I hear this, with a lot of people assuming that type 1 is primarily uncontrollably inherited and type 2 being a disease that is purely due to lifestyle, when this isn't true.
Many consider the rise in the number of type-2 diabetics as a result of an increase in seditary and glutinous lifestyle throughout the population i.e. less exercise and higher food consumption. Although there is a degree of truth to this, the whole truth may not have been as publicly explained.
The obesity epidemic which is thought to parallel the rise in diabetes helps predict that the number of diabetics will rise from 171million to 366 million in 2030! That's crazy numbers!

Despite having stated that type-2 diabetes has a strong genetic reliance, the mechanism by which this occurs still remains fairly elusive. However there are a number of gene candidates that contribute to a multifaceted genetic picture. Type-2 diabetes has a wealth of evidence to support its genetic origin, some argue, even more so than type-1 diabetes:

  1. Prevalence in varied ethnic groups: The prevalence of type-2 diabetes varies among populations from 2% among caucasians in Europe to 50% among Pima Indians in Arizona. The substantial variation amongst different ethnic groups is in support of the idea that genetic factors contribute to the predisposition.
  2. Aggregation amongst family: Despite families sharing environments and culture etc, familial aggregation shows strong evidence for genetic contribution. Especially considering that there is a 4-fold increased risk for type-2 diabetes in a sibling of a diabetic compared with the general population.
  3. Twins!: Twin studies reveal that there is a high consistency of mono zygote (same egg - same genes) diabetics as opposed to dizygote (2 separate eggs and therefore increase in different genes). These studies provide pretty compelling evidence of the genetic component of type-2.
  4. Inheritance of diabetic-like traits: insulin sensitivity and insulin secretion are known to deteriorate in type -2 diabetes. However both of these 'traits' are known to be present in non-diabetic but genetically identical twins born from a diabetic parent or descendant from a diabetic.
Main source: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1526773/

Lots of people will have some thought on particular disease's and possibly even attribute some individual blame, but no one really deserves disease… it just happens! The most important thing is dealing with the aftermath!! (Wow…can't believe I'm going to leave that last bit in)

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