…or is it?
It’s an exciting time to be alive and our genetic information is going to change health-care forever. I had my DNA tested via 23andme years ago before it was hugely popular, which was a simple process of spitting into a tube and sticking it in the post back to the States. I did it for ancestry purposes because we suspect some of my maternal forebears were Vikings who came over to Britain in the 700s AD to rape and pillage, and I didn’t really twig at the time that it would profile my health data. As it turned out, I am 100% European and do have Scandinavian DNA, though am now 71% British/Irish. The Irish doesn’t surprise me as we have lovely red hair in our family although my personal chance of being a red hair gene carrier is only 5%.
My DNA told me that I likely had wavy hair (true) and blue eyes (also true). That I would be crap at running (true) and not lactose intolerant (also true). More importantly I didn’t carry the BRCA breast cancer gene and was significantly less likely to develop Alzheimer’s Disease than the general population (no idea how they know this as we don’t know what causes Alzheimer’s and if we don’t know what causes a disease we also don’t know who will, or will not, develop it).
But then it got confusing. I am literally the spit out of my Mum’s mouth and both she, and my maternal Grandmother, had Dupytren’s Contracture yet according to my data I am at low risk of developing the disease myself. This could turn out to be true and I could be lucky, but being as though I have every other genetic trait my Mum possesses I somehow doubt it. My genes showed I do not flush after alcohol (another incorrect assumption), that I am not at risk of developing Restless Leg Syndrome when in fact I’ve had horrendous restless legs since childhood (both my parents have the disease), I’m no more likely to have Endometriosis than anyone else (I’ve had Endo since I was a teenager) and that there’s a high chance I was lower than average in birth weight when I was actually quite porky for a small framed baby at over 8lbs!
And there’s the rub. Just because our genes carry certain genetic codes doesn’t mean we will, or won’t, develop certain diseases. I don’t show highly for being either long or short sighted, yet I am both and started wearing glasses in my early 30s. It has nothing whatsoever to do with my actual eyesight, however. I have astigmatism, in other words the shape of my eyeballs is changing over time from being round like a football to being oval like a rugby ball and this is causing my eyesight to decline. My Optician strongly suspects this is connected to my Ehlers-Danlos and I probably agree with her. I may not genetically be pre-disposed to flush after alcohol, but the fact I have Mast Cell Disease and Histamine Intolerance means that I am highly sensitive to the biogenic amines in alcoholic drinks and it’s this which causes me to resemble a Lobster when I am drunk.
Genes are hugely complex and can be affected by both internal and external factors. The fact I have EDS, Endometriosis, MCAD and M.E. predisposes me to complications such as osteoporosis, retinal detachment, heart disease, female cancers and a host of other things, though if I didn’t have my pre-existing conditions I’d genetically not be pre-disposed to any of them.
We are all completely and utterly unique and lumping our DNA traits with other people’s and then extracting average data isn’t hugely helpful. My Mum obviously carries the EDS gene yet her symptoms are very minor compared to mine, so even if we are genetically predisposed to have a disease there is no way of knowing how severely, or not, it will manifest.
For the reasons mentioned above, I’ve never dabbled with genetics. It’s a massively complex area and we’re only in the very early stages of understanding how our DNA impacts our health or why someone without a gene mutation can develop a disease, while someone with the gene mutation doesn’t. How pre-existing conditions affect the expression of our genes or how genes can be turned on and off. So if you do go ahead and have your DNA tested don’t be lulled into a false sense of security, or conversely too alarmed, by the results. I just treat it as a bit of fun, though hopefully because I’ve opted into research on the 23andme site my genes might help our understanding of susceptibility to disease, if not our certainty.