Mean serum levels of amino acids in phenyketonuric patients and controls
| Plasma amino acid (μmol/L) | Diet incompatible group (n = 56) | Diet compatible group (n = 44) | Control group (n = 50) | P |
|---|---|---|---|---|
| Taurine | 72.46 ± 26.49 | 73.54 ± 30.14 | 79.69 ± 24.37 | 0.34 |
| Tryptophan | 52.11 ± 23.1 | 53.67 ± 19.63 | 48.64 ± 14.29 | 0.43 |
| Phenylalanine | 845.87 ± 380.03 | 162.68 ± 105.51 | 57.67 ± 16.76 | <0.001*** |
| Tyrosine | 53.7 ± 40.12 | 54.33 ± 24.72 | 69.09 ± 26.96 | <0.001*** |
| Leucine | 106.04 ± 55.11 | 94.27 ± 34.82 | 104.43 ± 33.26 | 0.35 |
| Methionine | 25.26 ± 10.69 | 25.66 ± 7.68 | 28.13 ± 9.87 | 0.26 |
| Isoleucine | 49.97 ± 24.4 | 41.98 ± 14.92 | 46.38 ± 17.95 | 0.14 |
| Asparagine | 39.3 ± 16.89 | 56.33 ± 21.3 | 59.79 ± 20.64 | <0.001*** |
| Proline | 213.87 ± 128.52 | 242.80 ± 103.59 | 246.58 ± 126.68 | 0.31 |
| Glutamine | 481.21 ± 126.66 | 511.62 ± 124.11 | 467.61 ± 120.82 | 0.22 |
| GABA | 0.96 ± 1.07 | 0.39 ± 0.7 | 0.32 ± 0.57 | <0.001*** |
| Citrulline | 32.93 ± 10.9 | 29.35 ± 8.7 | 31.99 ± 14.95 | 0.31 |
| Glutamic acid | 39.01 ± 22.94 | 80.47 ± 31.92 | 98.48 ± 42.54 | <0.001*** |
| Homocystin | 0.14 (0–1.85) | 0.23 (0–0.99) | 0.18 (0–1.96) | 0.2 |
| Cystathionine | 0.24 (0–0.85) | 0.3 (0–1.02) | 0.25 (0–1.36) | 0.67 |
| Cystine | 30.46 ± 13.13 | 31.77 ± 11.84 | 30.08 ± 9.86 | 0.75 |
| Arginine | 68.69 ± 25.75 | 72.84 ± 30.41 | 77.69 ± 27.13 | 0.25 |
| Hydroxylysine | 1.23 (0–32.58) | 1.18 (0–19.97) | 1.25 (0–11.3) | 0.13 |
| Ornithine | 69.99 ± 22.92 | 72.87 ± 31.58 | 79.32 ± 26.54 | 0.13 |
| Lysine | 138.69 ± 63.3 | 127.94 ± 50.06 | 121.52 ± 37.65 | 0.65 |
| Histidine | 58.14 ± 34.44 | 53.05 ± 21.52 | 50.82 ± 25.91 | 0.17 |
| 3-methylhistidine | 1.86 (0.36–16.8) | 1.71 (0.16–4.39) | 1.98 (0.30–5.95) | 0.34 |
| 1-methylhistidine | 1.35 (0.23–5.99) | 1.1 (0.48–7.47) | 1.04 (0.42–9.74) | 0.72 |
| Valine | 190.56 ± 91.52 | 169.54 ± 62.43 | 171 ± 55.76 | 0.26 |
| Threonine | 109.75 ± 56.74 | 117.71 ± 38.93 | 114.67 ± 45.54 | 0.70 |
| Serine | 132.62 ± 40.3 | 140.07 ± 42.70 | 144.5 ± 31.99 | 0.30 |
| Alanine | 321.10 ± 129.26 | 372.5 ± 136.02 | 345.72 ± 145.27 | 0.17 |
| Aspartic acid | 11.91 ± 7.19 | 12.38 ± 6.98 | 13.1 ± 10.26 | 0.75 |
| Glycine | 305.1 ± 105.19 | 202.82 ± 73.99 | 174.73 ± 102.28 | <0.001*** |
| Hydroxyproline | 9.50 ± 3.35 | 9.94 ± 3.95 | 9.98 ± 2.35 | 0.7 |
Sociodemographic characteristics of the patients
| Diet incompatible group (n = 56) | Diet compatible group (n = 44) | Control group (n = 50) | P | |
|---|---|---|---|---|
| Sex (male/female) | 30/26 | 27/17 | 27/23 | 0.69† |
| Age (mean ± SD) (min–max) years | 6.57 ± 3.99 (0–14) | 6.75 ± 4.62 (0–16) | 6.36 ± 4.58 (0–16) | 0.15‡ |
| Parental consanguinity | ||||
| Yes/no n (%) | 49 (87.5)/7 (12.5) | 33 (75)/11 (25) | 11 (22)/39 (78) | <0.001† |
| Refugee status | ||||
| Yes/no n (%) | 16 (29)/40 (71) | 4 (9)/40 (91) | 5 (10)/45 (90) | 0.01† |
| Lenght percentile (n) | 0.96§ | |||
| 3–10 p | 8 | 5 | 5 | |
| 10–25 p | 10 | 8 | 13 | |
| 25–50 p | 14 | 14 | 16 | |
| 50–75 p | 9 | 5 | 5 | |
| 75–90 p | 6 | 6 | 6 | |
| 90–97 p | 5 | 5 | 5 | |
| Weight percentile (n) | 0.82§ | |||
| 3–10 p | 6 | 5 | 5 | |
| 10–25 p | 10 | 8 | 13 | |
| 25–50 p | 12 | 14 | 17 | |
| 50–75 p | 12 | 7 | 5 | |
| 75–90 p | 9 | 5 | 5 | |
| 90–97 p | 7 | 5 | 5 | |
Correlation between plasma levels of phenylalanine and other amino acids
| Correlated factors | r | P |
|---|---|---|
| Phenylalanine–GABA | 0.462 | <0.001 |
| Phenylalanine–glycine | 0.511 | <0.001 |
| Phenylalanine–asparagine | −0.412 | <0.001 |
| Phenylalanine–glutamic acid | −0.475 | <0.001 |
Post hoc analysis of blood plasma amino acid levels with significant differences
| Amino acid | DIC–DC | DIC–Control | DC–Control |
|---|---|---|---|
| Phenylalanine | <0.001 | <0.001 | <0.001 |
| Tyrosine | >0.99 | <0.001 | 0.004 |
| GABA | 0.005 | <0.001 | 0.92 |
| Glycine | <0.001 | <0.001 | 0.47 |
| Asparagine | <0.001 | <0.001 | 0.81 |
| Glutamic acid | <0.001 | <0.001 | 0.06 |