Amino acid levels modified in autism
An example of how glutamate and glycine can transmit in the brain to n-methyl-d-alanine (NMDA) receptor sites	Amino acids These are the small molecules that make up all proteins but are also used to some degree in as transmitters in the nervous system, generally in the brain.   The problems with these findings is generally that they have not been duplicated by further researchers.  Also, many of the reports have not been published and as such cannot be included here.

Problems: Notice that some of the studies were difficult to repeat and the large number of patients that got tested in the USA by independent companies did not find anything particularly odd

 

Evans C, Dunstan HR, Rothkirch T, Roberts TK, Reichelt KL, Cosford R, Deed G, Ellis LB, Sparkes DL. Altered amino acid excretion in children with autism. Nutr Neurosci. 2008 Feb;11(1):9-17. (Significantly lower relative urinary levels of essential amino acids were revealed for both the untreated (mean +/- SEM, 32.53 +/- 3.09%) and treated (31.98 +/- 2.87%) autistic children compared with the controls (37.87 +/- 1.50%). There were no significant differences in measured excretions of sugars or tartaric acid.)

 

Aldred S, Moore KM, Fitzgerald M, Waring RH. Plasma amino acid levels in children with autism and their families. J Autism Dev Disord. 2003 Feb;33(1):93-7. Raised glutamic acid, phenylalanine, asparagine, tyrosine, alanine, and lysine (p < .05) than age-matched controls, with reduced plasma glutamine. Other amino acids were at normal levels. This suggests a general disorder of amino acid metabolism in their families.

 

Arnold GL, Hyman SL, Mooney RA, Kirby RS. Plasma amino acids profiles in children with autism: potential risk of nutritional deficiencies. J Autism Dev Disord. 2003 Aug;33(4):449-54. (No amino acid profile specific to autism was identified. However, children with autism had more essential amino acid deficiencies consistent with poor protein nutrition than an age/gender matched control group.)

 

Jackson MJ, Garrod PJ. Plasma zinc, copper, and amino acid levels in the blood of autistic children. J Autism Child Schizophr. 1978 Jun;8(2):203-8. (no abnormal levels were found)

 

Winsberg BG, Sverd J, Castells S, Hurwic M, Perel JM. Estimation of monoamine and cyclic-AMP turnover and amino acid concentrations of spinal fluid in autistic children. Neuropediatrics. 1980 Aug;11(3):250-5. ( CSF cyclic adenosine monophosphate (cAMP) was been found to be elevated in autistic children.  They put it down to brain metabolism. )

 

Low methionine levels not uncommon (Observation by J. Pangborn) (I could not find this article).

 

Shinohe A, Hashimoto K, Nakamura K, Tsujii M, Iwata Y, Tsuchiya KJ, Sekine Y, Suda S, Suzuki K, Sugihara G, Matsuzaki H, Minabe Y, Sugiyama T, Kawai M, Iyo M, Takei N, Mori N. Increased serum levels of glutamate in adult patients with autism. Prog Neuropsychopharmacol Biol Psychiatry. 2006 Dec 30;30(8):1472-7. Epub 2006 Jul 24. (they did feel that suggests that an abnormality in glutamatergic neurotransmission may play a role in the pathophysiology of autism)

 

 Moreno-Fuenmayor H, Borjas L, Arrieta A, Valera V, Socorro-Candanoza L. Plasma excitatory amino acids in autism. Invest Clin. 1996 Jun;37(2):113-28. (they showed no particular oddity for the levels of taurine in the  blood of autistic children but eleven (of 14) children had increased aspartic acid and eight children had high levels of glutamate; seven of these children had a concomitant increment of taurine.)

 

Below normal glutamine (14 of 14), high glutamate (8 of 14) (Invest Clin 1996 June; 37(2): 112-28) (I could not find this but it may be referring to Moreno’s paper above)

 

 

Urinary Amino acids:

i)  Evans C, Dunstan HR, Rothkirch T, Roberts TK, Reichelt KL, Cosford R, Deed G, Ellis LB, Sparkes DL. Altered amino acid excretion in children with autism. Nutr Neurosci. 2008 Feb;11(1):9-17.  In this study, 34 autistic children (12 untreated and 22 receiving therapeutic treatments related to digestive function and nutritional uptake) and 29 control subjects (all 5-15 years of age) were investigated to determine whether there were any anomalies in the urinary excretion of amino acids, glucose, sucrose, arabinose and tartaric acid using GC/FID and GC/MS analysis techniques. Significantly lower relative urinary levels of essential amino acids were revealed for both the untreated (mean +/- SEM, 32.53 +/- 3.09%) and treated (31.98 +/- 2.87%) autistic children compared with the controls (37.87 +/- 1.50%). There were no significant differences in measured excretions of sugars or tartaric acid. NB One of the most obvious differences between autism and control was in the levels of tryptophan which was dramatic.  This would make sense with other factors seen in the blood.