Tag: Down Syndrome

Non-invasive first trimester testing for Down syndrome

By Razib Khan | June 9, 2013 9:45 pm

Fetus at ~12 weeks

I am going to get back to the eugenics debate at some point, but it is hard to motivate myself. This is due to a combination of complacency and sanguinity. Many of those who use eugenics as a “scare word” or are “very concerned about it” don’t really seem to get past generalities when it comes to the present situation (i.e., there is detailed exploration of past atrocities, and some exploration of rather unrealistic scenarios, such as occurred with the “Chinese eugenic” story, but little concrete engagement with realities such as the high abortion rates for positive tests for Down syndrome). In more crass and intellectually vapid discussions liberals and conservatives tend to use eugenics as a term of selectively useful instrumental rhetoric, a bludgeoning instrument only in the mindless screaming discourse.

Meanwhile, we have advances like the whole genome sequencing of second trimester fetuses. This is still basic science, but in genomics basic science is translated really fast to the consumer market. I’m ~90 percent sure my daughter will have a 10 x whole genome sequence by the end of 2014 (I might even get her parents in on the game for a trio). So, submitted for your interest are two papers on first trimester noninvasive screens for Down syndrome due to aneuploidies (and other syndromes). Non-Invasive First Trimester Blood Test Reliably Detects Down’s Syndrome and Other Genetic Fetal Abnormalities:

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CATEGORIZED UNDER: Health

Why some people don't think Down Syndrome is bad

By Razib Khan | July 13, 2012 7:16 pm

I often criticize Lefty readers for their lack of reality-basis. Specifically, they often want to align reality with their own normative preferences, even though normative preferences aren’t necessarily contingent upon reality (e.g., sex differences). My post on Down Syndrome has elicited similar responses, but from people one might term social conservatives. So, for example, Ursula and Matthew Hennessey have taken to denouncing me on Twitter, albeit for statements that they no doubt find extremely objectionable. Not too surprising. But I found this post, A gift named Magdalena, particularly instructive:

But we aren’t victims. In fact, we’re the opposite. We are supremely lucky. Magdalena isn’t sick. Down syndrome is not a disease; it’s merely a collection of traits, all of which occur, though not all at once, in so-called “normal” people.

But how could Down syndrome be a gift? Surely that’s taking it too far. How could a lifetime of likely dependency be a gift? How could impaired cognitive development be a gift? How could gastroesophageal reflux disease and its expensive, twice daily medicine be a gift? How could two full years of potty training with no end in sight be a gift?

The truth is that there is no objective bright line between trait and disease. In fact, nature does not know trait or disease, it only knows phenotypes. Being white skinned in a pre-modern world is a disease at the equator, and being black skinned in Scandinavia would also have been a disease. In theory you could argue that Down Syndrome is not a disease either. The Hennessey’s are correct that the collection of traits of DS individuals can be found elsewhere. So imagine that a chemical exposure or some such thing functionally transformed a child with a normal karyotype into one with Down Syndrome. How would most people feel about this? Would parents view it as a gift?

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CATEGORIZED UNDER: Health
MORE ABOUT: Down Syndrome, Theodicy

I think Down Syndrome is bad

By Razib Khan | July 12, 2012 11:04 pm

An interesting comment:

“If you add copies of a gene the result is not always good because of dosage effects (Down Syndrome is an extreme case of this on the smallest chromosome).” [From my post, -Razib]

As a father of a child with Down syndrome, I would take exception to this comment. First DS, is not “bad” – my daughter is an amazing and wonderful person, and her DS is part of that wonderful person. She is one of the most amazingly positive things that has ever happened in my life. So I have a hard time reconciling that with your “extremely bad” synopsis.

Second, DS is not an at all extreme case – it is rather run of the mill. It is so minor of a variant that it is survivable and very common place (1 in 733 births). People with DS lead full, productive and meaningful lives. That is not extreme, it is mild. Extreme would be being born inside out or having no chance of surviving 72 hours.
Please don’t add to the misconceptions around Down syndrome. Most of us parents, siblings, and self-advocates find this to be both untrue and unhelpful.

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CATEGORIZED UNDER: Bioethics
MORE ABOUT: Down Syndrome

Eugenics by another name

By Razib Khan | June 18, 2012 10:03 pm

Evolution’s winner. Real headline.


In the mid-2000s two British biologists of some public note attempted to revive or resuscitate the good name of eugenics, Richard Dawkins and Armand Leroi. My own suspicion is that this emerges in part from a implicit cultural history in the British Isles in regards to eugenics: in those nations,* unlike in the USA or Germany, eugenics was generally conceived of in the positive rather than negative sense. By this, I mean that a disproportionate amount of thought was given to the procreation of the favored, rather than coercive restriction of the unfit. This is exemplified by R. A. Fisher, the co-founder of both evolutionary genetics and statistics, who worried about the high mortality rate of the British elite during World War I. Fisher himself went on to have eight children, a situation which occasionally left him in financial distress, as would be predicted from standard Malthusian assumptions (see R.A. Fisher: The Life of a Scientist).

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CATEGORIZED UNDER: Bioethics, Personal Genomics
MORE ABOUT: Down Syndrome, Testing

Noninvasive tests for Down Syndrome

By Razib Khan | December 29, 2011 10:54 am

I’ve mentioned this before, but I thought I’d pass on the latest report on MaterniT21, the prenatal noninvasive Down Syndrome test. Currently it has a $235 copay for women with insurance. As of now only a few percent of the ~5 million pregnancies in the USA are subject to amnio or c.v.s. This procedure may result in the screened proportion going from ~1 percent to ~50 or more percent (though the firm that is providing this can only process ~100,000 tests per year as of now). I stumbled upon this after doing a follow up on my post, Would you have your fetus genetically tested? Interestingly the proportions who would get tested doesn’t differ that much between demographics.

And the outcomes can sometimes surprise. A story in the Columbus Dispatch relates the story of a couple who kept their daughter, who tested positive for Down Syndrome. They had originally decided that if the tests came back positive the would terminate. In contrast, the nurses relate that one strongly anti-abortion couple at the beginning of the process seems to have terminated. Right now 1 in 700 pregnancies result in Down Syndrome.

CATEGORIZED UNDER: Bioethics
MORE ABOUT: Down Syndrome
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This blog is about evolution, genetics, genomics and their interstices. Please beware that comments are aggressively moderated. Uncivil or churlish comments will likely get you banned immediately, so make any contribution count!
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