Friday, 20 February 2015

Down Syndrome

The culprit- 'bad chromosome'


As my regular readers are aware, I'm a professional human geneticist. I reached the profession, via a tortuous route, many years ago. Prior to working in a genetics lab, I was a botanist. I couldn't make the transition these days, my background and degrees are all wrong. Arse.

Yesterday, I gave a talk to my colleagues and peers about Down syndrome. Most folk have heard of Down syndrome. It is the most common of the chromosome disorders and is caused by an additional chromosome 21 raising the human chromosome complement from 46 to 47. The presence of the extra 300 genes causes disruption to normal embryogenesis resulting in the stigmata associated with typical Down syndrome, and of course the intellectual deficit.  

Down syndrome individuals are instantly recognisable. There is a collective ‘look’ about them that’s not just confined to their highly distinctive facial features. You could identify a Down syndrome person from behind, I’m sure, without seeing their face. Their gait, their whole habitus, is instantly discernable.

They suffer from a whole host of medical problems due to that pesky extra chromosome. Congenital heart disease and other organ defects are common. There is also an increased incidence of leukaemia and an inherent predisposition to other conditions. The thrust of my lecture was concerned with the phenomenon of premature ageing and Down syndrome; tis a well described feature of the condition.

Ageing is a strange disease and we are still not sure why it occurs. We don’t all age at the same rate. I’m not talking chronological age, but biological age. Clearly, ageing is a complex choreography between our genetics and the way we choose to live our lives. Genetics plays a greater role than most doctors let on to their patients. I suppose this is a ‘trick’ to make us live healthy lives, but in most instances the tactic fails miserably. But regardless, some of us are genetically favoured and some less so. Down syndrome individuals fall conclusively into the latter category. Not only do they age faster than the general population, they also have reduced life expectancy. With old age come the diseases of old age. Arthritis and degenerative physical disease come to the fore. We become less mentally acute and are prone to the neurodegenerative diseases, such as Alzheimer’s. Thus is the great pageant which is life (bugger nuts). Down’s individuals experience all this, but earlier.

Life expectancy in the civilised world has been climbing steadily over the past 100 years, and in parallel, the life expectancy for the Down’s population has soared. In 1929 live expectancy was 9 years, whilst today it is closer to 60. Better health and medical care are the likely causes. Although, I suspect in times of yore, infanticide was overtly or covertly practiced.

The incidence of Down syndrome is on the wane. This is due to improvements in prenatal screening. Theoretically, at least, and in the ‘ideal’ hospital setting 90% of Down’s pregnancies can be identified by a maternal blood test together with a detailed ultrasound scan. This is a screening test with many false positives and the definitive diagnosis still requires an invasive test and an examination of foetal chromosomes.  Most women choose to terminate when confronted with a foetus with a chromosomal disorder. And let’s be honest, who can blame them.

Over recent years, Down syndrome advocacy groups have arisen. They argue that Down syndrome individuals can lead happy and fulfilling lives. This cannot be denied. From my experience, parents choosing to terminate a Down's pregnancy are devastated. Terminating life should never be easy. The fact that most couples decide to terminate reflects reality. Raising and caring for a Down syndrome child is  exacting, draining, and emotionally and economically punishing. Their potential child will never live a full and independent life, and they know it.

The extreme end of the Down syndrome advocacy group use highly charged emotional terms and arguments not rooted in fact, or reality. Some argue that to terminate a Down's pregnancy is akin to eugenics and have the temerity to compare it to Hitler's programme of enforced 'euthanasia' for the mentally feeble. They do themselves no justice with such arguments and comparisons and only serve to raise spurious content which adds nothing to the furtherance of frank and honest debate.

Personally, I am firmly with the parents and their brave decisions. Caring for and raising  a child without mental disability is challenging enough. To embark on the journey knowing the route and the final chilling destination is a parental burden few would knowingly take.     



Bert, the oldest living Down syndrome. Died at 83
     



Anyway, I’m off to drink beer and smoke a good cigar with my son….                 



5 comments:

  1. My very dear friend who now lives in NZ has a downs son, she was screened during her pregnancy but the downs was not revealed she was only 29, maybe in those days screening was not as effective I don't know.
    Her son then contracted Leukaemia when he was 18 months old, he was a real fighter and made it through that, they then discovered he was partially deaf so we all learnt sign language so we could communicate with him, and he could adequately let us all know what he needed. He was a very intelligent child and they then discovered he was on the autistic spectrum. after 11 years of repeated issues with him she was exhausted, she had separated from his father (mainly due to the stress involved and the pressure on the relationship) later she remarried but things with her son got no easier and eventually she could cope no longer and sent him to live with his dad. I know what it cost her emotionally to admit she was struggling and could no longer cope, now a good few years later even his dad is beginning to feel the strain and has decided he needs full time residential care, he is 18 now and a charming young man. He has been physically very strong since he was 7 and this caused my friend a lot of issues when he was young, he also has no boundaries and does not understand inappropriate behaviour. Had she known whilst pregnant her son was Downs , she has made no bones of the fact that she would most likely have opted for abortion. Given all his other issues over the years that may have been a sensible option for her, the stress definitely made her old before her time. But personally I think the world would have been a much sadder place without him he has such a great sense of humour is so loving and loves life.

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    1. Kath, I absolutely agree. Life ain't simple, is it?

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  2. Bloody 'ell, Flaxen - that was heavy stuff but then life is heavy isn't it?

    So, Professor Flaxen, what do you know about Congenital Hyper Insulinism?

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  3. Update: I placed a comment on the site I linked to. Nothing too contentious, just an invitation to debate. Of course, my comment never appeared. Extremists, of every persuasion, are not interested in debate. They just want to foist upon us their version of reality. I've been on committees to discuss the issue of 'Down syndrome'. It consists, in the main, clinicians and scientists. However, there is always an individual from a Down syndrome advocacy group. Fair enough. I'm aware that diverse opinions should be aired and debated. What has struck me, rather forcibly, is the lack of coherence from the fore mentioned individual. She is strident and more concerned at shouting down any view which contradicts her narrow viewpoint and she is clearly not interested in worthwhile debate. Pehaps she would make a good politician?

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