Twins and autism: a response

A very short post this one, I promise.

Following the revelations yesterday that the genetic contribution to autism 'might' have been inflated, there has been quite a lot of scientific and media interest in this whole debate. I say media interest, but here in the UK we have heard diddly squat so far about the revelations that identical twins appear to show a not so high rate of autism than fraternal twins. I don't know why.

Anyway, I would like to draw attention to this opinion piece published in the Archives of General Psychiatry (online) by Dr Peter Szatmari of McMaster University and his take on the implications of the Hallmayer paper. Szatmari is no stranger to autism research having published extensively with papers such as this one and this one.

He is fairly candid in his opinions on the 'game changer' that was the Hallmayer paper and the implications for the early concordance studies such as that from Folstein and Rutter in 1977, asking "where did the heritability go?". Whilst I wouldn't like to give a definitive answer to this complicated question, I would perhaps suggest that we should start by looking at the participant numbers included in the Folstein paper - 21 twin pairs. That's all. Forty-two participants. That is pretty much what the whole 'genetics are king' argument was originally based on. I know that this study has been replicated in other participant groups but be under no disillusion that the 1977 paper cast the die.

Many, many people have been talking about the variable relationship between genes and environment in autism down the years. I'd like to think that once the dust has settled and further corroborative work completed (part of which should be appearing in the journal Pediatrics soon), autism research can finally move out of its 'obsession' with purely genetic models of autism and start moving itself into that brave new world in which genes work in unison with environment. At least so no more parents enter a Doctors office to be told blanket that 'autism is genetic' and nothing else.