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Table 10 Table of Primary Amino Acids in Plasma The average levels measured in the Autism and Neurotypical groups are reported below, in units of μmol/dl, along with their standard deviations

From: Nutritional and metabolic status of children with autism vs. neurotypical children, and the association with autism severity

Amino Acids Autism Group Neuro-typical Group % Difference p-value Neurotypical Reference Range (10th and 90th percentiles) Autism Group % below RR Autism Group % above RR Tietz Ref. Range Lepage et al Reference Range at 6 yr (top) and 16 yr (bottom)
Essential Amino Acids          
Histidine 8.84
+/- 2.0
8.2
+/- 1.3
  0.06 6.4-9.8 15% 36%   6.3-9.3
7.7-10.7
Isoleucine 5.26
+/- 1.0
5.8
+/- 1.6
-9% 0.05 4.1-8.3 16% 0% 3.8-9.5
(6-18 yr, serum)
4.0-6.9
4.7-7.4
Leucine 10.7
+/- 2.2
10.7
+/- 2.1
  n.s. 8.2-13 13% 11% 7.9-17.4
(6-18 yr, serum)
8.6-13.6
10.1-15.9
Lysine 13.5
+/- 3.8
14.5
+/- 4.8
  n.s. 8.7-22 11% 2%   9.6-18.1
15.7-24.2
Methionine 1.83
+/- 0.46
1.75
+/- 0.34
  n.s. 1.4-2.3 16% 13% 1.6-3.7
(6-18 yr, serum)
1.4-2.5
2.0-3.4
Phenylalanine 4.45
+/- 0.62
4.83
+/- 0.83
-8% 0.01 3.9-6.0 20% 0% 4.8-10.9
(adult, serum)
4.0-6.1
4.7-7.4
Threonine 9.25
+/- 2.9
8.88
+/- 2.1
  n.s. 6.7-11 18% 16%   6.5-12.5
10.4-18.8
Tryptophan 3.49
+/- 1.2
4.33
+/- 1.0
-19% 0.001 * 2.7-5.6 24% 4%   3.7-7.6
5.4-9.3
Valine 19.5
+/- 3.8
20.5
+/- 4.3
  n.s. 16-27 16% 4% 15.6-28.8
(6-18 yr, serum)
16.5-23.4
17.8-27.5
Other Amino Acids          
Alanine 36.4
+/-10.5
33.4
+/- 8.9
  n.s. 24-45 7% 18% 19.3-54.5
(6-18 yr, serum)
18.2-31.9
24.0-48.2
Arginine 6.50
+/- 2.4
6.7
+/- 1.8
  n.s 4-9.35 16% 9%   5.0-9.9
6.8-12.8
Asparagine 4.33
+/- 1.0
4.40
+/- 0.85
  n.s. 3.6-5.7 30% 8%   3.1-6.7
3.7-8.1
Aspartate 0.71
+/-0.29
0.78
+/- 0.38
  0.08 0.39-1.25 8% 6%   0.3-0.6
0.2-0.5
Cystine (oxidized form of cysteine) 3.22
+/- 0.82
3.48
+/- 0.74
  n.s. 2.4-4.25 15% 11%   
Glutamate 6.5
+/- 1.5
5.5
+/- 1.3
+18% 0.001 * 4.2-7.7 6% 26%   1.3-6.5
1.1-4.6
Glutamine 43.3
+/- 9.0
41.6
+/- 6.9
  n.s. 34-52 16% 20% 36-74
(6-18 yr, serum)
49.3-72.4
55.1-79.7
Glycine 26.7
+/- 8.1
27.3
+/- 10.1
  n.s. 16-39 4% 6%   14.4-28.2
18.3-32.2
Proline 15.7
+/- 5.5
15.8
+/- 4.9
  n.s. 11.5-24 20% 7%   9.3-20.1
11.3-27.1
Serine 10.4
+/- 2.5
9.47
+/- 2.1
+10% 0.04 6.9-12 5% 15%   9.6-15.5
10.1-17.7
Tyrosine 5.51
+/- 1.2
6.1
+/- 1.6
-10% 0.03 4.8-8 31% 4% 4.4-7.2
(adult)
3.9-6.5
4.6-8.7
  1. The p-value for a t-test comparison of the two groups is also reported. If the p-value is below 0.05, then the % difference between the groups is reported, and the result is highlighted.
  2. The table also lists the reference range of the neurotypical group (10th and 90th percentiles), and the % of the Autism group who are above or below the reference ranges. Note that if the groups were identical, 10% would be above and 10% would be below. Percentages above 25% are highlighted. Reference Ranges from Tietz Textbook of Clinical Chemistry are given for serum amino acids where available. For Lepage et al, the reference ranges are the 10th and 90th percentiles for ages 6 yr and ages 16 yr.
  3. * Statistically significant difference between the two groups with 95% confidence per Bonferroni analysis.