Genetic testing predicts ginger hair

Photo credit: nio_nl on Flickr

How would you like to know if there’s a chance your child will have ginger hair? This is the test that is being offered to couples by scientists in London at next months ‘Who Do You Think You Are?’ heritage show.

A saliva test will reveal to them the presence of variants of the MC1R gene, which is responsible for red hair. It is a recessive gene, which means that both parents must be carriers in order for a child to be born with the hair colour, and even then, there is only a one in four possibility.

Owing to its recessive nature, the gene can be passed down for generations in a family, but only emerges when a child is produced with another carrier- this is why ginger hair can appear seemingly out of nowhere.

This sounds like an intriguing way to pass an afternoon, but what are the more serious applications of genetic testing? Ask yourself this: how would you like to know the possibility that you or your children will develop a debilitating and ultimately fatal disease?

Huntington’s is a neurodegenerative condition for which symptoms generally present between the ages of 30 and 50. Memory loss, confusion, aggression, changes in personality, and uncontrolled muscle movements, which can often be mistaken for clumsiness in the earlier stages, are all of the characteristics that await someone born with the mutated form of the responsible gene.

Unlike in the case for red hair, this is a dominant gene. If you have the mutation in chromosome 4, then no amount of healthy eating, exercise, or looking after your body can save you from the 15- 25 year decline that Huntington’s promises.

This terrifying reality means that the decision of whether or not to take the blood test for the disease is an immensely difficult one. There have been cases of suicide in people who have found out that they have the Huntington’s gene. Counselling is available for those who have taken a genetic test, or are thinking about doing so.

One could argue that it would be better to know how many years of your life you have left, so that you can make the most of it. This is not an opinion shared by many, however, as only 20% of those potentially at risk take the test. Many financial problems can arise for those with a family history of the disease in the areas of insurance or mortgages.

Before having children, many might prefer to have the test in order to determine whether they risk passing this fate onto their offspring. The problem is, a lot of people will have already have reproduced by the time symptoms begin to show.

The model for genetic testing that began with Huntington’s has influenced that for many other diseases including familial Alzheimer’s and breast cancer.

It is also incredibly useful in the diagnosis of cystic fibrosis, an autosomal recessive genetic disorder affecting the lungs, pancreas, liver and intestine. A lung transplant is often an inevitability for someone with CF. Diagnosis before birth can allow the parents to make vital choices.

While the decision to have these tests is difficult, it can help with many life decisions regarding career, family planning and relationships. If you don’t take the test, but know you risk having the mutation; is there a chance that you will forever live in the shadow of the disease.

Whether using it to divine your fate, or the colour of your child’s hair, it cannot be denied that genetic testing is an extremely powerful tool.

One comment

  1. What are the prospects of using gene therapy to treat Huntington’s? I know clinical trials for gene therapy for cystic fibrosis are ongoing.

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