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Doctors
Find Early Warning
Indicator For Autism
WASHINGTON
(Reuters) - Elevated levels of proteins in the blood at birth
appear to foreshadow the development of autism and mental retardation
later in childhood, researchers said on Wednesday in a finding
that could lead to earlier diagnosis and better treatment.
Researchers
studied archived neonatal blood samples from children born in
four northern California counties from 1983 to 1985 who were later
diagnosed with autism, mental retardation, cerebral palsy or developed
normally.
They found
that concentrations of proteins in the blood called neural growth
factors were significantly elevated in children who later developed
autism or mental retardation, but not in the other children. The
findings appear in the journal Annals of Neurology.
Dr. Karin
Nelson, who led the study, said the discovery of this early-warning
indicator for the development of autism and mental retardation
before the onset of symptoms could help doctors make earlier and
more definitive diagnoses.
Nelson, who
works at the National Institute of Neurological Disorders and
Stroke, part of the US government's National Institutes of Health,
said the research could point the way for developing drugs that
could be used in children showing these early-warning signs to
better treat and perhaps prevent the development of autism.
Nelson said
despite the similarities in these early biological markers for
autism and childhood mental retardation, there is no reason to
think they are the same disorder.
Autism, a
developmental disorder, affects up to one in 500 children. Diagnosis
generally is not made until after symptoms surface at about age
2. The children are unresponsive to human contact and exhibit
poor language development and bizarre behavior such as uncontrollable
head banging and screaming fits.
A Poorly
Understood Malady
``The basic
biology (of autism) has been fundamentally not understood,'' Nelson
said in an interview.
``These kids
look normal, most of them, and they move normally. For a long
time it was thought that this was a psychological disorder caused
by defective parenting. Now it is pretty clear this is an organic
disease of the brain.''
The study
found that children who later developed autism or mental retardation
had, on average, three times as much of certain brain growth factors
in their blood as the other kids. The finding that these major
regulators of brain development differ in autistic children in
the first days of life helps in the understanding of the malady's
biological basis, she said.
``Things are
happening after birth that make one hopeful that there may be
ways found to intervene,'' Nelson said. ``Many people think that
the earlier you start treatment, the more favorable the outcome.''
Neural growth
factors are important to the formation of the central nervous
system during embryonic development. Previous research found that
many of these proteins are crucial in the production of new brain
cells and the organization of those cells into distinct networks.
The researchers
said the abnormal abundance of these proteins in the autistic
and retarded children may disrupt the normal process of cell migration,
differentiation and programmed death during early nervous system
development.
Animal studies
have shown that an early shortage of one of these proteins leads
to microcephaly (a brain defect marked by a small head and mental
retardation) and other developmental problems.
Nelson said
``gorgeous foresight'' by the California Department of Health
Services to save blood specimens from the state's newborn screening
program made the findings possible.
The department's
Judith Grether, a co-author of the study, said the archive provides
``a tremendously valuable resource for scientific study of a wide
range of developmental disabilities and birth defects.''
Reference
Source 89
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