Autism links
on chromosome 7
Revised DNA sequence homes in on
break points.
11 April 2003
HANNAH HOAG
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| 100 new points on chromosome 7 have been associated with genetic disorders. |
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A revamp of chromosome 7's
DNA sequence has brought to
light genes associated with
autism, several leukaemias and
lymphomas1.
Geneticist Stephen Scherer,
of the University of Toronto,
and his colleagues identified
the site of more than 100 new
mutations linked to genetic
disorders after studying the
genetic makeup of more than 300
new patients and reviewing 1,570
published studies.
Doctors will be able to log
onto a new dynamic database in
which the sequence anomalies are
held, and determine whether a
patient's genetic make-up
matches those of others. As
information is added to the
free-access database, more
mutations may stand out. "It's a
quick way to identify candidate
genes for a disorder," Scherer
says.
Some of the mutations seen in
patients with autism have turned
up in genes related to speech
and communication, others are
close to genes that enable
neurons to communicate.
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A single gene change doesn't seem to be sufficient in most families
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Beth Rosen-Sheidley
Tufts University
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The genetics of autism is
complex, warns Beth
Rosen-Sheidley of the Tufts-New
England Medical Center in
Boston. "A single gene change
doesn't seem to be sufficient in
most families." Any test for the
disease would be difficult to
interpret, she says. "It's a bit
of a quagmire. One marker for
the disease might increase the
risk, but by how much?"
To produce a precise map,
Scherer's team started with the
draft chromosome 7 sequence
published by the private company
Celera Genomics2.
They then filled in many of the
gaps with data from the
international public consortium3.
The researchers admit that
the resulting sequence is not
completely finished, but reckon
that it is in good shape. Others
feel, however, that it has some
way to go. |
