New Autism Gene Doubles Risk
Finding Suggests Autism Is Disease of Brain and Body
Oct. 16, 2006 -- A single gene mutation doubles a child's susceptibility to
autism, a Vanderbilt-led
research team reports.
It's a discovery with far-reaching implications. Why? It isn't specifically
a brain gene. In fact, it affects multiple systems in the body, including
immune function and gut repair. The gene in question is a variant form of a
gene called MET.
This suggests that the complex set of behaviors and mental disabilities we
call autism may not, as previously thought, be solely a problem with brain
development. It may also be linked to subtle developmental problems throughout
The study, which included Pat Levitt, PhD, of the Vanderbilt Kennedy Center
for Research on Human Development, appears in the early online edition of the
Proceedings of the National Academy of Sciences.
"We hypothesize that the common, functionally disruptive [MET gene
variant] can, together with other vulnerability genes and [genetic] and
environmental factors, precipitate the onset of autism," Levitt and
New Autism Gene Important
Kids with autism usually seem normal at first. Then they seem to backslide,
losing abilities they once had and suddenly withdrawing into their own
There are many theories about why this happens. Clearly, something goes
wrong with normal development.
The MET gene, Levitt and colleagues note, encodes an important enzyme called
the MET receptor. Among other things, the MET receptor sends out signals
important for brain growth, brain maturation, immune function, and gut
Many parents of children with autism report that their kids have digestive
problems and haywire immune responses. It's never been clear whether this is
directly or indirectly linked to their autism.
Linking the MET gene to autism opens the door to exciting new research,
notes Matthew W. State, MD, PhD, director of the neurogenetics program at Yale
University. State's editorial accompanies the Levitt team's report.
"The possibility that a MET variant might lead to immune dysfunction and
gastrointestinal disturbance along with autism-spectrum disorders is an
important question to pursue and one that will likely lead to some debate,"
That's because the first theory to link autism, gut problems, and immune
dysfunction blamed these symptoms on childhood immunization with the measles/mumps/rubella (MMR)
That theory has been retracted by all but one of the researchers who first
proposed it. Moreover, an Institute of Medicine expert panel has rejected the
Now the MET gene findings offer new insights into the link between autism
and other developmental problems.
"The very important question of whether and how gut disturbance,
regression, and immunological issues may be related has been, in part, obscured
by this controversy," State writes. "Hopefully, the present study will
lead to additional rigorous investigations of these questions without fueling
unnecessary concern regarding MMR."