Would you test your child’s genes?

The undisputed fact is that children inherit 50 percent of their genes from each parent, but these genes include millions of variations which accounts for the differences between all human beings

The undisputed fact is that children inherit 50 percent of their genes from each parent, but these genes include millions of variations which accounts for the differences between all human beings

Published Jun 29, 2011

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London - When I look at my two daughters, it seems fairly obvious who takes after me - and who takes after my husband, Anthony.

My older child, Lily, nine, has the same chestnut hair, taller build, profile and bone structure as her father.

But Clio, six, looks more like my side of the family - she’s slighter, shorter for her age, with a rounder face and fuller mouth. Their personalities also seem to fall along similar lines.

Clio is, dare I say it, a bit more type-A like me, while Lily opts for a more easy-going approach to life, like her father.

As we’ve watched their characteristics and looks emerge, Anthony and I have wondered how much of the children is down to the genes they’ve inherited from us - and how much is down to fate and the environment.

The undisputed fact is that children inherit 50 percent of their genes from each parent, but these genes include millions of variations which accounts for the differences between all human beings,

So I was intrigued when I came across a US genetic testing company, 23andMe, which could tell us whether Lily really is more of “a Harwood” (my husband) and Clio “a Carey”.

But it wasn’t a step I took lightly. Beyond just satisfying our curiosity, I was also aware that we could be delving into some frightening territory.

Every week scientists are discovering more genetic variants pinpointing risks of serious illnesses, such as heart disease, Alzheimer’s and cancer.

As there’s a history of autoimmune diseases on my father’s side (he died of a rare muscle-wasting disease at 57) and of depression on my mother’s side, I knew we might have to face up to some difficult truths about conditions which could affect the health of our daughters long after we’re both gone.

However, on reflection, Anthony and I reasoned that forewarned is forearmed and we could take preventative steps and arrange for better screening if we knew what faulty genes we’d passed on.

The test cost $99 (about R700) per family member, plus a small monthly subscription to get updates - and was based on a sample of all our saliva sent away for processing. Our genetic codes were then compared with thousands of studies isolating the implications of different genes.

Six weeks later we received our results. At first glance, the array of charts was overwhelming, covering everything from whether we had the wet or dry form of earwax (gene-related - and yes, ours is wet) to whether we can taste the bitter flavour in brussels sprouts (we all can). The good news is that I’ve discovered that I, as well as Lily and Anthony, have the version of the ACTN3 gene linked to better sprinting ability. Although I didn’t consider myself sporty at school, this might have explained why I won the mums’ race on sports day.

As to the child who resembles each parent the most, our guesses were right: Clio is indeed more like me than Lily. It seems Clio has 85.2 percent of my gene variations and Lily has 90 percent of Anthony’s.

Although research into what many variations mean is still in its infancy, Clio has inherited my fairer genes - which accounts for her lighter skin and hair - while Lily is closer to Anthony’s darker colouring.

Meanwhile, another group of genes could account for the fact that both Clio and I are unable to get up in the mornings. Around 90 percent of Lily’s body clock genes are like Anthony’s who, like her, always manages to jump out of bed at 5.30am. Meanwhile, Clio’s body clock genes are less like his - 87.24 percent, which might not sound like much of a difference, but when you crunch the numbers it means she’s inherited thousands more of my variations. This might explain why she’s as grumpy as me in the mornings.

What’s so interesting is that the girls share 88 percent of the same gene variations - which means they’re more similar to each other than to Anthony or me.

In fact, Lily and Clio are so similar in immune compatibility - 100 percent - that they could be organ donors, a strangely comforting thought.

But looking through the more serious health findings felt like a very scary visit to a fortune teller.

Our analysis gave us the risk factors for 97 diseases, including the top nine we have the most probability of contracting.

I recognised several because other members of the family had suffered from them.

For example, Anthony and both girls have raised odds of coeliac disease - a severe reaction to gluten, a protein in wheat - which is what two of their cousins on his side of the family have. Lily also has a higher chance of polycystic ovarian syndrome - an imbalance of the sex hormones - a condition I’ve suffered from.

But there were other health problems I didn’t recognise from our family tree, like the fact all four of us were likely to be lactose intolerant (to date, none of us has any apparent problem with dairy).

Probably the most alarming finding was that the biggest health risk for both Anthony and me is atrial fibrillation or irregular heartbeat, which usually comes with old age. This can cause blood clots and strokes. Anthony has a one in three chance of developing atrial fibrillation, while my chance is one in four.

Out of the litany of potential nasty illnesses on the screening list, including several cancers, Parkinson’s and schizophrenia, this seemed mercifully minor.

But because of our high risk, the risk is also elevated in our children (with a 30 percent risk compared with the average, 15.9).

Coincidentally, atrial fibrillation was not a condition I’d heard of until that week, when I rang an aunt who’d just been admitted to hospital with a suspected blood clot (she told me she’d suffered from an irregular heartbeat for years). But at least I now know what we might be up against - and can look out for ways of monitoring it. The other sobering result was my raised risk of breast cancer - 18.3 percent compared with 13.5 percent for women my age. Lily has inherited the same risk as me.

Nearly one in eight women will face breast cancer at some point; Lily and I have odds of around one in five.

Until now, it was a disease I’d never worried about, although I now recall my great aunt had died of it.

But as I’ve never been screened at the age of 43, it certainly brought my need to start having annual scans into sharp focus.

However 23andMe’s senior director of research Dr Joanna Mountain stresses there is still much to learn.

For one thing, there are around 10 million variations in the human genome- 23andMe’s reports look at just over a million.

Many of the disease risks are also based on a small handful of research studies, for most diseases there’s a lot more work to be done.

“Gene testing won’t determine your future, but it can point you in the right direction,” she adds.

Dr Helen Wallace of watchdog Genewatch believes while genetic test kits can provide an entertaining insight, a little knowledge can be a dangerous thing.

“Some bits of the information, about whether you have dry or wet earwax for example, are just a bit of fun,” she says.

“But tests for genes that play a role in breast cancer, and other serious diseases, shouldn’t be sold on the internet.

“Many common diseases have hundreds of different genes and these results are testing for just a handful. You’re really only getting a few pieces in a very big jigsaw puzzle.

“For most diseases, factors such as diets or pollution are much more important.”

Genetic testing companies are not regulated and have been found to give clients widely divergent predictions of their chances of developing serious diseases, she adds.

So am I falsely reassuring or scaring myself, based on some very limited, or even inaccurate knowledge?

Possibly. But even so, I’ve already been in touch with my GP about breast cancer screening, and I will also impress on my daughters the importance of monitoring their health.

And in the short-term, Clio and I now have the perfect excuse for enjoying a morning lie in. - Daily Mail

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