A TV show about Bruce Jenner’s transformation? I’m totally gonna watch that.
Siblings with autism have different varieties of autism. Different broken genes. The implication is that autism may not be inherited and that autism isn’t one thing. It isn’t merely one broken gene, rather it’s a bunch of different mutant genes creating lots of different kinds of autism.

“autism isn’t one thing. It isn’t merely one broken gene, rather it’s a bunch of different mutant genes creating lots of different kinds of autism.”
I would have thought the “autism isn’t one thing” part was blindingly obvious. I’m not 100% sure it’s a “bunch of different mutant genes” as opposed to a bunch of different causes, though who knows. But it’s really clear that “autism” as we know it is a series of symptoms, not a single thing with one etiology. It’s just too wildly different (even before the diagnosis got as wide as it is now) from case to case to be one thing.
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So, why the prevalence of siblings with autism, then?
From a few years back:
“Parents who have a child with autism have about a 1 in 5 chance of having a second child with autism, a far greater risk than previously believed, new research shows.”
http://well.blogs.nytimes.com/2011/08/16/autism-risk-for-siblings-higher-than-expected/
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I like the link to the Economic Policy Institute for that study on growing income inequality: http://www.epi.org/publication/income-inequality-by-state-1917-to-2012/.
I thought the really interesting analysis was the examination of what percent of income gains in the last decade have gone to the top 1% v the bottom 99%.
Interesting headline at the WSJ — I think it’s only in NY and environs that people think of the income inequality as being “wall street”. On the west coat we think of it as being ipo/stock market related (i.e. owning those things, rather than skimming the transactions).
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“They found that these sibling pairs [with autism] shared the same autism-relevant gene variations only about 31% of the time,’
That might be enough to explain the increased risk with siblings, though the conditionals make the calculations complicated.
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Oops, the three last anonymous’s are me. bj. And I was wondering why my posts weren’t appearing.
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I wonder if the ‘siblings with autism’ is due to some degree with parents being more familiar with the symptoms by the time number two or three rolls around, and therefore they are more likely to identify the child as having issues, seek treatment (know where to go to get it) and have the child therefore eligible for treatments, interventions, etc. I’m thinking about our youngest who is a mildly autistic girl — Chances are if she were an only child and if we had not had experiences with her brother previously, we might not have ever figured out that sensory seeking behavior, sensory issues, hyperlexia, etc. even were autism symptoms. We probably would have just thought she was a kind of nerdy little girl — but since her brother stimmed, including verbal tics, etc. we were therefore sensitized to her having issues as well. He wasn’t identified until he was eight, but we had a grasp on his sister’s issues before she started kindergarten.
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Yeah, that’s occurred to me before, too.
But there’s still the question–why so many in the same family if it’s not hereditary?
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But there’s still the question–why so many in the same family if it’s not hereditary?
Could be: common environment. Or, if as people sometimes think, it’s something that’s related to older parents, this could more common in some families than others. There are probably other reasons, too. Lots of things are more common within families than between them that are not hereditary. Now, maybe it’s all hereditary, or maybe there are importantly hereditary causal contributors, but what we know doesn’t imply that, and certainly does not imply that it’s “one thing” as opposed to several different types of things that have a number of similar symptoms but different causal etiologies.
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