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The open-access scientific journal BMC Biology is currently hosting an interview with Martin Raff, presenting his responses to questions about autism. Prof. Raff gives the background in simple form well.

A neurobiologist with an excellent scientific pedigree Professor Raff did not study autism during his research career, but became interested in it after he retired when his grandson was found to be autistic.

BMC Biology has placed a copy of their interview in two parts on YouTubeâ„¢, which I have included below. A transcript of the interviews can be found on the BMC website for those that prefer to read it rather than listen. There are references to further reading at the end of the transcript.

Opinions on autism seem to invariably considered controversial to some degree, a skepticism that can be healthy. An over-riding cause of autism has not formally been identified. Individuals who, unlike Prof. Raff, assert that they know ’for certain’ ’the’ cause of autism are speaking beyond present-day evidence. Be aware of the distinction between what is known and what is suspected, possible or – dare I say it – guessed.

YouTube Preview Image

YouTube Preview Image

I would add a quick word about epigenetics to his comments about genetic causes of autism.

Epigenetics* is a form a regulation of genes that can cause stable states in genes that can last a long time (e.g. the lifetime of the cell or person).

I previously wrote about epigenetics on Saturday (see I remember because my DNA was methylated) where I made an analogy to a complex electrical circuit, with typical gene regulation being akin to altering the levels of current in the wires and epigenetic alterations being similar to throwing switches altering what parts of the circuitry were to be used.

It is possible that epigenetic control of gene expression may, in part, help explain why despite autism being a strongly genetic disorder it has been hard for researchers to identify genetic alterations that characterise autistic people.

One form of epigenetic change is a chemical modification to a DNA base. (Most commonly, methylation of a cytosine base.) Older methods to search for genetic alterations associated with a disease look for changes in DNA sequences, but do not look for the chemical modifications that epigenetic changes make. More recent studies are looking for epigenetic changes. Another possibility that Prof. Raff mentions is that many different rare genetic alterations are present in the autistic population, with different ones in different people.

Footnotes

Many months ago I wrote an article ’Autistic children and blood mercury levels.’ I ended that article saying that I wanted to move past rebuttals in response to what we hear from the anti-vaccine crowd towards what might cause autism. I never did for a host of reasons. In a small way, I hope this article might make up for this. Another, shorter, ’for the general public’ explanation of the elements of autism can be found on the Autism New Zealand website.

* When I write ‘epigenetics’ I am referring to molecular epigenetics, characterised covalent modification of DNA and/or histone proteins, not the wider meanings that some people seem to have for this term.


Other articles on Code for life:

Autistic children and blood mercury levels

Media thought: Ask what is known, not the expert’s opinion

Monday potpourri: maps, malaria in the USA, cholera in Dunedin and vaccines

Minorities, disabilities and scientists

Deleting a gene can turn an ovary into a testis in adult mammals