Table 1. Comparison of metabolic condition spectrum and clinical features of infantile hyperammonemia with different ages of onset.

Clinical features	Total, N=85, n [%]	Neonatal, N=32, n [%]	<1 year, N=53, n [%]	P value
Metabolic condition spectrum
OA	12 [14]	10 [31]	2 [4]	0.001
FAOD	5 [6]	5 [16]	0 [0]	0.006
UCD	6 [7]	4 [13]	2 [4]	0.416
Cholestasis	47 [55]	6 [19]	41 [77]	<0.001
Clinical features
Peak NH3 ≥500 μmol/L	9 [11]	8 [25]	1 [2]	0.003
Neurologic abnormality	26 [31]	21 [66]	5 [9]	<0.001
Respiratory failure	13 [15]	11 [34]	2 [4]	<0.001
Circulatory failure	6 [7]	4 [13]	2 [4]	0.192
Hepatic failure	7 [8]	0 [0]	7 [13]	0.042
Severe infection	8 [9]	5 [16]	3 [6]	0.146
Malformation	9 [11]	4 [13]	5 [9]	0.935
Metabolic acidosis	20 [24]	14 [44]	6 [11]	0.001
Hyperlactacidemia	6 [7]	3 [9]	3 [6]	0.668
Glucose metabolic disturbance	22 [26]	13 [41]	9 [17]	0.016
Electrolyte disturbance	12 [14]	9 [28]	3 [6]	0.010
Treatment
Arginine	31 [36]	16 [50]	15 [28]	0.051
CRRT	2 [2]	2 [6]	0 [0]	0.133
Precision medicine	30 [35]	16 [50]	14 [26]	0.027
Clinical course of HA
Self-limited	23 [27]	5 [16]	18 [34]	0.065
Controllable	44 [52]	14 [44]	30 [57]	0.251
Refractory	18 [21]	13 [41]	5 [9]	0.001
Clinical outcomes
Improved	56 [66]	12 [38]	44 [83]	<0.001
Withdrew treatment	22 [26]	15 [47]	7 [13]	0.001
Died	7 [8]	5 [16]	2 [4]	0.098

OA, organic acidemia; FAOD, fatty acid oxidation disorder; UCD, urea cycle disorder; CRRT, continuous renal replacement therapy; Precision medicine refers to special formula or diet, drugs and liver transplantation; HA, hyperammonemia.