Friday, November 12, 2010

Autism in a Lab Dish? Call Me Unconvinced

The hot autism news of the day is that scientists have replicated autism spectrum disorder in a lab dish. A study published in Cell asserts that the authors have used stem cells to develpop  neurons.  I am not convinced. 
Maybe someday when we know what autism actually is we can replicate it but today when we can not yet agree on whether autism includes those with no obvious life functional limitations and when very serious challenges facing the 75-80% of persons with Autistic Disorder who also have significant intellectual disabilities are dismissed as resulting from co-morbidities I don't understand how anyone can claim to have replicated autism spectrum disorder in a petri dish.
Interestingly the Cell study Abstract indicates that Rett syndrom was used as an autism spectrum genetic model:
Autism spectrum disorders (ASD) are complex neurodevelopmental diseases in which different combinations of genetic mutations may contribute to the phenotype. Using Rett syndrome (RTT) as an ASD genetic model, we developed a culture system using induced pluripotent stem cells (iPSCs) from RTT patients' fibroblasts. RTT patients' iPSCs are able to undergo X-inactivation and generate functional neurons. Neurons derived from RTT-iPSCs had fewer synapses, reduced spine density, smaller soma size, altered calcium signaling and electrophysiological defects when compared to controls. Our data uncovered early alterations in developing human RTT neurons. Finally, we used RTT neurons to test the effects of drugs in rescuing synaptic defects. Our data provide evidence of an unexplored developmental window, before disease onset, in RTT syndrome where potential therapies could be successfully employed. Our model recapitulates early stages of a human neurodevelopmental disease and represents a promising cellular tool for drug screening, diagnosis and personalized treatment.
The DSM-5 working groups have recommended that Rett's Disorder not be included in the DSM-5. The rationale for excluding Rett's Disorder is based on it's very specific and known etiology and the brevity of the autism like symptoms of the condition:
Rett's Disorder patients often have autistic symptoms for only a brief period during early childhood, so inclusion in the autism spectrum is not appropriate for most individuals.

Like other disorders in the DSM, Autism Spectrum Disorder (ASD) is defined by specific sets of behaviors and not by etiology (at present) so inclusion of a specific etiologic entity, such as Rett's Disorder is inappropriate.
Given the DSM-5 position on excluding Rett's Disorder from the Autism Spectrum Disorder it is difficult for this humble dad to see how a genetic model based on Rett's can be said to result in a replication of ASD in a dish.
I absolutely support autism research,including stem cell research, but the claim itself blaring in news headlines that autism has been replicated in a petri dish is in need of a good scrubbing with some  soap and water.

1 comment:

emma said...

I've seen various claims referring to "helping the understanding of ASD" with research into Angelman Syndrome, the research may be relevant to ASD in the long run but the claims made are misleading.

Of course, all these researchers are frequently competing for funding...