Proposed Causes of Autism - Disorder in Glutamate Regulation and Microglial Activity

The incidence of autism spectrum disordersa condition called excitotoxicity occurs which can
(ASD) has increased to the alarming rate oftrigger abnormal development of the nervous
approximately 1 in 100, and in some areas of thesystem. Studies have indicated that there is a
country, as many as 1 in 67 males are afflictedgenetic abnormality in the regulation of glutamate
with the condition.in individuals with ASD.
ASD is a related group of neurodevelopmentalAlso a part of the picture is an inflammatory
disorders including autism, Asperger's syndrome,process in the central nervous system (CNS).
Rett's syndrome, childhood disintegrativeImmune cells in the CNS, called microglia, remove
syndrome, and pervasive developmental disorderdamaged nerve cells from the brain and CNS.
not otherwise specified (PDD-NOS).However, when microglia are chronically active,
Until now, researchers have not proposed athey release damaging chemicals.
theory that pinpoints a single mechanismChronic activity of the microglial cells leads to CNS
responsible for causing the diverse constellation ofdamage and has been implicated in a number of
behaviors characteristic of ASD. A research studyneurodegenerative diseases including Alzheimer's
published in Current Medicinal Chemistry proposesdisease, Parkinson's disease, and multiple sclerosis.
that environmental and dietary factors mayIn 2005, brain autopsies of individuals with ASD
trigger a devastating cycle of events affectingconfirmed the presence of significantly increased
certain activities of the brain.levels of microglial cell activation.
In their recent paper, researchers R.L. BlaylockBlaylock and Strunecka comment, "As a
and A. Strunecka propose that increased levels ofmultifaceted disorder, ASD requires a multifaceted
glutamate, a neurotransmitter involved in moreapproach, one that should include the protection
than half of the brain's neural transmissions, isagainst excitotoxicity/microglial activation."
implicated in ASD.They warn of the significant dangers of long-term
Glutamate is essential for learning, memory,fluoride use, ingestion of aluminum, and diets
motor coordination, and many other braincontaining processed foods, and
functions. However, too much glutamate in theaspartate-containing additives. They recommend
brain has toxic effects. The level of glutamate is"nutrition with special nutrients that have been
regulated by a sophisticated feedback system. Ifshown to reduce excitotoxicity and microglial
this complex feedback system becomes impaired,activation.