Plasma amino acid levels in a cohort of patients in Turkey with classical phenylketonuria

	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

† Pearson chi-square test;

‡ one-way ANOVA;

§ Fisher exact test;

SD: standard deviation.

Table 2

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

SD, Standard deviation; GABA, γ-aminobutyric acid.

Mean ± SD and P-value for the one-way ANOVA and median (min–max) and its P-value for the Kruskal–Wallis test are given.

*** P < 0.001.

Table 3

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

[i] DC, diet compatible group; DIC, diet incompatible group; GABA, γ-aminobutyric acid.

[ii] One-way ANOVA with Bonferroni post hoc correction applied.

Table 4

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

[i] r, Pearson correlation coefficient; GABA: γ-aminobutyric acid.

References

Authors

Metrics

Articles in this issue

DOI: https://doi.org/10.1515/abm-2020-0009 | Journal eISSN: 1875-855X | Journal ISSN: 1905-7415

Journal RSS Feed

Language: English

Page range: 59 - 65

Published on: Aug 4, 2020

Published by: Chulalongkorn University

In partnership with: Paradigm Publishing Services

Keywords:

amino acids,

chromatography,

diet therapy,

neurotransmitter agents,

phenylketonuria

Related subjects:

Medicine,

Assistive professions, nursing,

Basic medical science,

Basic medical science, other,

Clinical medicine,

Clinical medicine, other

© 2020 Kazanasmaz Halil, Karaca Meryem, published by Chulalongkorn University
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Volume 14 (2020): Issue 2 (April 2020)