Wednesday, August 23, 2017

Reading the Research: Twins, Genes, and Autistic Traits

Welcome back to Reading the Research, where I trawl the Internet to find noteworthy research on autism and related subjects, then discuss it in brief with bits from my own life, research, and observations.

Today's article discusses what causes autistic traits, which has been an argument pretty much since autism got onto the public radar.  After all, when you find out your kid isn't normal and probably never will be, the first thing a lot of parents ask is, "Oh God, what did I do wrong?"

The answer, according to this article, is "Absolutely nothing."  This study is one of literal hundreds, if not thousands, to address the question, and the arguments have gone back and forth between "nature," i.e., genetics, and "nurture" i.e., environment, parenting tactics, diet, exercise, neurotoxins, etc.  I suspect, with sufficient research, you could come up with a docket full of studies that loudly proclaim that autism is definitely mainly caused by either side.

I'm bringing this particular study to your attention because it studied twins, and thousands of them at that.  Usually psychological studies are very limited in their sample sizes, such that a hundred or so participants is regarded as "pretty decently good." In this case, the study was able to draw a large sample size (over 19,000 pairs of twins, both identical and fraternal), but had to rely on parental perspectives and reports for its data.  While parents know their kids best, there can also be bias, which decreases the reliability of the study.  Still, a sample size of nearly 39,000 twins is pretty impressive.

The current thinking for "what causes autism" is that genetics are involved, but so are environmental factors, such as air pollution, diet, traumas, etc.  This study pins the heritability of autistic traits at over 75%, moreso for girls than for boys.  It also suggests that the same genes are responsible for girls being autistic as for boys.

As for me, I've never personally seen my own genetic records.  But if autism runs in the genes, I can point to a few family members that have or had some autistic traits.  Maybe not full blown autism, like myself, but enough that it might explain me.

Whatever the cause of autism ends up being, I'm keeping tabs on my niece and nephew.  If either of them end up being autistic, my brother and his wife might like my help sorting out what to do with their kid.  They're both highly educated, intelligent people, and I'm sure they'd do a stellar job without me, but there's nothing like first person experience to tell you what books can't.  Which was kind of the impetus for this entire blog.

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