Table 1.
Neurotransmitters and neurotrophins. AUC: Area Under the Curve; ASD: Autistic Spectrum Disorder; HC: healthy controls; and SD: standard deviation.
| Lab test | Increase | Decrease | P values | Receiver Operating Characteristic (ROC) | Diagnosis | Age (Y): range (mean ± SD) |
Number M/F |
Control group | Country | Biologic sample | Technique | Reference | |||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cut-off values | Sensitivity | Specificity | AUC | ||||||||||||
| GABA (μmol/L) |
∗ | 0.001 | 0.170 | 90.0% | 80.0% | 0.883 | ASD | 3–12 (7.0 ± 2.34) |
52 male |
HC | Saudi Arabia | Plasma platelet-free | ELISA | [37] | |
| Serotonin (ng/mL) | ∗ | 0.001 | 59.925 | 100.0% | 100.0% | 1.000 | |||||||||
| Dopamine (ng/L) |
∗ | 0.001 | 477.771 | 92.9% | 88.9% | 0.968 | |||||||||
| Oxytocin (μLU/mL) | ∗ | 0.001 | 92.105 | 90.0% | 100.0% | 0.981 | |||||||||
|
| |||||||||||||||
| Serotonin (ng/mL) |
∗ | <0.001 | 111.20 | 78.79% | 80.65% | 0.86 | Autism | (12.21 ± 2.67) | 27/6 | HC | China | Whole blood | HPLC | [36] | |
|
| |||||||||||||||
| Brain-derived neurotrophic factor (BDNF) (ng/mL) | ∗ | <0.0001 | 15.0 | 71.7% | 86.7% | 0.830 | ASD | (3.78 ± 1.22) | 48/12 | HC | China | Serum | ELISA | [38] | |
|
| |||||||||||||||
| Brain-derived neurotrophic factor (BDNF) (ng/mL) | ∗ | <0.0001 | 12.65 | 80.8% | 70.2% | 0.840 | ASD | (4.0 ± 1.25) | 62/13 | HC | China | Serum | ELISA | [39] | |
|
| |||||||||||||||
| Gamma aminobutyric acid (GABA) (ng/mL) | ∗ | <0.001 | |||||||||||||
| Serotonin (5HT) (ng/mL) | ∗ | <0.001 | High level of sensitivity and specificity | Autism | 4–12 | 25 | HC | Saudi Arabia | Plasma platelet-rich |
ELISA | [54] | ||||
| Dopamine (DA) (ng/mL) | ∗ | <0.001 | |||||||||||||