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: