Torsion Dystonia

There’s a mutation found in Ashkenazi Jews (not common – maybe 1 in 2000 frequency) that, in the opinion of a number of a number of those that have dealt with patients, makes you smarter. It’s a low-penetrance dominant. Some people never have trouble with it, some have moderate trouble (writer’s cramp), some end up with crippling muscle spasms. A friend of a friend has it – just writer’s cramp – but her neurologist comforted her a bit by pointing out that “it makes you smart”.

You’d think that people would be super-interested in this – but they’re not. I talked to a guy who, years ago, stumbled onto torsion dystonia at NIH and was quite excited, but nobody else here wanted to investigate it. Too interesting, probably.

Do I think that higher-than-average Jewish IQ is mediated by single-gene effects like this? Probably not most of it – probably the main thing is slightly higher frequencies of the kind of IQ-plus variants we’re getting from GWAS studies. Maybe some of it – some of the mutations causing relatively common Ashkenazi genetic diseases ( like Tay-Sachs and Gaucher’s disease) sure have unusual neurological effects.

Like anything that hurts children, it’s hard to read about. For example:

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31 Responses to Torsion Dystonia

  1. AppSocRes says:

    It seems like most of these single gene mutations that appear to be associated with increased intelligence are associated with many serious diseases of the CNS.

    A bit off topic but I vaguely remember reading that the increased intelligence of Ashkenazi Jews is not across the board but is evident only in areas that cultural selection might account for, e.g., arithmetic skills, verbal skills, and logical reasoning are critical skills for successful merchants, traders, and courtly bureaucrats. As I remember the example that was given to support this claim was that Ashkenazi Jews score on average no better at (or maybe a bit worse) than other Europeans in tests that measure the ability to mentally rotate three dimensional objects. Does anyone know anything about this.

    • Anonymous says:

      Not just mental rotation, but most visual tasks. Block design, embedded figures, all sorts of things. Visual IQ vs verbal IQ seems to be something that can vary a great deal across different populations; Eskimos are an interesting example of the other side of the equation.

      • j says:

        White Americans and Germans rule the rarefied world of 3D autocad engineering design, that requires exceptional ability for mental manipulation of objects and pipes. I see some Latin immigrants but few Asians or Indians in this field. I dont think it is inborn, but what I know.

    • MawBTS says:

      How about chess? Seems like there’s a bit of visual IQ going on there (particularly in the movement of the knight).

    • melendwyr says:

      If I recall correctly, Ashkenazis score about one standard deviation above the norm on IQ tests – IF you look at total IQ. If you look at specific performances, they’re two STDs above average at language and normalish at spatial. They’re not smarter generally, but smarter in particular and specific ways, and constitute a good counterargument to the idea that overall cognitive efficiency is the key to IQ.

  2. whyteablog says:

    Rolling in myopia with the diseases you’ve talked about gives a higher proportion of that 11 point gap as being caused by “disease” in general.

    Makes me think about eugenics. I imagine you’d want to select for IQ on the whole, but select against dirty brain genes that cause other problems.

    • JW Bell says:

      Myopia can be from increased computer use.

      • whyteablog says:

        Lot of those data re: race and myopia rates are old. 1960s, maybe earlier.

        • ilkarnal says:

          IIRC lack of UV exposure causes myopia – the reason you spend all day inside doesn’t matter, just that you spend all day inside.

          • whyteablog says:

            Correlative or causative relationship? If couch potatoes are smarter- which would honestly surprise me- flow of causality could go the other way around, for example if already-smart people were more likely to stay indoors.

          • benespen says:

            I’ve read some studies claiming such, and it seems plausible, but I’m not sure it is truly causal yet. For example, has anyone checked to see if myopia is less prevalent at high altitudes? All else being equal, living at higher altitude means more UV, so if UV exposure prevents myopia, it should be less prevalent among people who live at high altitudes.

            • seppia says:

              There is a study on children from Hongkong (or Singapore?) which moved to Australia. Those that moved were significantly less myopic than those who stayed in Hongkong.

              • benespen says:

                Do you have a citation for that? I’d like to read it.

              • seppia says:

                I read about this study in a book (I don´t remember the name anymore but it was about paleo lifestyle 😉 ) Now I found some links that sound similar to this research: “One study found that 30 per cent of ethnic Chinese six-year-olds in Singapore had myopia, compared with just 3 per cent from the same ethnic group in Australia.”

                Or study about sunlight and children:

              • benespen says:

                Thanks, that was an interesting study.

      • erica says:

        Reading or close work as a child, in general, I’ve heard.

    • Bob says:

      Myopia appears to be environmentally caused, and reversible:

      • whyteablog says:

        Interesting concept; I’ll have to check out that video later.

        Speaking off the cuff, a phenotype that tends to run in families (myopia) is probably at least partially heritable. Even if environment plays a role, genetics likely do as well, meaning that between group differences are likely caused at least in part by genetics.

        So I’d bet on myopia constituting a significant chunk of that gap- not most of it, but a pretty good fraction.

        By what I’m sure is total coincidence, other commenters point out that the subtests where they don’t crush us Gentiles just-so-happen to be visual. Oy vey!

  3. The mother’s story is well told and very moving. On a small sample, in fact a reasonably sample if one controls for rarity it is associated with a 10 IQ gain, which is massive.

    • ghazisiz says:

      I agree, the mother told a very moving story. Thank you, Sharon Drew Morgen, for sharing the story, and thank you Greg, for passing it on.
      Even with today’s technology such tragedies can be avoided. The parents must be tested, when both carry the allele they must go the in vitrio route.

  4. Old fogey says:

    I will say an extra “thank you” prayer tonight to the Lord for my two strong and healthy sons and my two strong and healthy grandchildren.

  5. Had an undergrad student with it last semester. Very smart, interested, talkative, despite mild disformation of the jaw. Certainly in the upper bounds of the first quartile, at least in terms of curiosity and inquisitiveness.


  6. dearieme says:

    “Too interesting, probably.” I hooted in appreciation.

  7. Dave chamberlin says:

    Another area too interesting to research are those genes expressed in brain function that we received from Neanderthals that have some strongly positive influence because they are now shared by up to 60% of the population.

    Why one could postulate that we are the result of a hybridization of the best intelligence enhancing genes of multiple archaic populations. African, neanderthal, basal Eurasians (one of the first three farming populations had this signature yet little to no neanderthal) and of course newer mutations. These genes aren’t impossible to find because they have risen to higher frequency than chance for a reason.

    But let’s not look. Too interesting..

  8. Rappaport says:

    Torsion dystonia increase verbal or general intelligence on ashkenazi?

  9. Bob says:

    In your paper on the natural history of Ashkenazi intelligence, you suggested that a side effect of selection for higher IQ in urban environments among the Ashkenazim would be lower fitness in more typical environments and competitive disadvantages in things like farming and hunting-gathering. What sorts of traits and differences would these disadvantages in more typical environments and occupations look like?

  10. neal says:

    Perhaps selection for what is called intelligence has something to do with exposure to intense geomagnetic flux and plasma discharge. I know that the traces of old stuff usually involve both.

    Probably seemed rather animistic at the time. Now, just genetic encoding lapsing into matter after a brief migration. Best to save that for the next wave of activity.

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