Table 1.

Characteristics of CKD and control group

	CKD (n = 12)	Control (n = 15)	P value
Age, y	12.3 ± 5.4	6.5 ± 2.8	0.12
Male (%)	10 (83)	3 (20)	0.0018 **
Height, cm	149.1 ± 30.1	116.6 ± 14.2	0.22
Body weight, kg	44.3 ± 22.2	19.7 ± 7.4	0.17
Body mass index, kg/m²	17.9 ± 4.8	15.8 ± 2.1	0.37
Body surface area, m2	1.39 ± 0.48	0.79 ± 0.18	0.083
Gestational age, week	38.0 ± 5.7	39.0 ± 1.8	0.47
Birth weight, g	2923 ± 1102	3036 ± 577	0.37
Creatinine in the serum, mg/dL	0.81 ± 0.36	0.35 ± 0.071	< 0.0001 ****
Cystatin C in the serum, mg/dL	1.17 ± 0.39	0.80 ± 0.10	< 0.0001 ****
β2-microglobulin in the serum, mg/dL	2.4 ± 0.99	1.3 ± 0.34	0.0001 ***
d-asparagine in the plasma, nmol/mL	0.187 ± 0.080	0.118 ± 0.027	0.0002 ***
l-asparagine in the plasma, nmol/mL	49.8 ± 8.6	45.1 ± 9.6	0.24
d-/l-asparagine ratio in the plasma, %	0.412 ± 0.11	0.278 ± 0.07	0.0006 ***
d-serine in the plasma, nmol/mL	2.29 ± 0.70	1.84 ± 0.31	0.06
l-serine in the plasma, nmol/mL	113 ± 15.0	142 ± 19.2	0.0004 ***
d-/l-serine ratio in the plasma, %	2.21 ± 0.70	1.35 ± 0.16	< 0.0001 ****
Urinary d-asparagine, nmol/mgCre	22.1 ± 13.4	31.2 ± 37.4	0.21
Urinary l-asparagine, nmol/mgCre	74.1 ± 55.3	131.9 ± 71.3	0.032 *
Urinary d-serine, nmol/mgCre	138.9 ± 52.5	271.2 ± 0.46.5	< 0.0001 ****
Urinary l-serine, nmol/mgCre	163.2 ± 147.1	325.5 ± 156.7	0.028 *
d-/l-asparagine ratio in the urine, %	23.5 ± 16.3	20.4 ± 7.1	0.24
d-/l-serine ratio in the urine, %	104.6 ± 75.5	84.9 ± 30.2	0.32
Creatinine based FED−asparagine, %	67.2 ± 26.2	68.1 ± 14.8	0.58
Creatinine based FED−serine, %	45.5 ± 11.4	48.5 ± 7.3	0.34
eGFR_Cre, mL/min/1.73 m²	77.0 ± 19.0	116.5 ± 12.8	< 0.0001 ****
eGFR_CysC, mL/min/1.73 m²	81.2 ± 21.1	122.3 ± 15.7	< 0.0001 ****
eGFR_β2-microglobulin, mL/min/1.73 m²	71.7 ± 25.4	115.6 ± 26.8	0.0002