By Philip Hunter
British researchers have launched a major study into the effect of genetics and environment on autism, hoping to resolve controversies over the causes and definition of autism spectrum disorders.
The Medical Research Council (MRC) has given a team from Bristol
University £400,000 to study autism using data from the Children of the
90s study, a long-term project assessing the impact of environment and genes on the developing health of 14,000 children.
Lead researcher Jean Golding said the study should resolve once and
for all the controversy over the alleged link between the measles, mumps,
and rubella (MMR) vaccine and autism that has rumbled on ever since Andrew
Wakefield’s famous Lancet paper and subsequent press conference in 1998.
In fact, the project is one of four into autism supported by the MRC
from funds that were allocated to take forward recommendations of the 2001
MRC Review on Autism, which was partly a response to concerns raised by
Wakefield.
The other three projects include a collaborative brain imaging study, led by Declan Murphy at the Institute of Psychiatry, King’s College London, and studies led by Kate Nation, at the University of Oxford, and Tony
Charman, at the Institute of Child Health, to understand more about how
cognition relates to behavior in people with autism spectrum disorders.
The Bristol study was welcomed with some caveats by Paul Shattock
from the UK Autism Research Unit in Sunderland. “There’s a whole range of
possible environmental triggers, and given the size of this study, they
should be able to tease out which ones are significant,” Shattock said.
“So I’m pleased they’re moving away from a totally genetic grounding to
consider environmental factors.”
Shattock urged the study’s researchers to keep an open mind over the
alleged MMR link, but said he was not convinced that even a study this
size will finally resolve the MMR question. Given that the incidence of autism
is about 1 in 140, and that of these children, around 7 to 11% have parents
believing there is such a link, there might be no more than 10 of them
within the 14,000 sample, Shattock said.
Golding insisted the team will assess the possible MMR link with an open mind. “But I’d be surprised if it turns out there is a link,” she said.
Golding said she hoped the study would help define autism and
Asperger syndrome. “What this research is doing, that previous work hasn’t, is try and untangle the different traits.”
The study is also focusing on the possible links between autism and
gut bacteria passed from mother to child during pregnancy, although only
via indirect data on the state of the mother’s bowel movements, according to
Golding. But one question the study will not be able to answer is whether
the incidence of autism has been increasing over the last 30 years, as is
commonly believed, or whether improved diagnosis is the reason for greater
patient numbers. “I don’t think we’ll be able to answer that because our
study is a snapshot in time,” said Golding.
The study was called a positive step forward by the UK National
Autistic Society. “However, until the outcomes of these new research
studies are seen, the significance of their contribution to understanding the
development of autism will remain undetermined,” said Stuart Notholt, the
society’s director of policy and public affairs.