Table 3. Liver stiffness as assessed by SWE.

Summary statistics are mean +/− SD for continuous variables and counts with percentages for categorical variables. Results are stratified by liver stiffness (normal and abnormal). To evaluate (univariate) association of each characteristic with liver stiffness, we used t-test to compare means of continuous variables and chi-square tests to compare proportions of categorical variables. The data from one participant was excluded because the IQR/median was greater than 0.3, thus making the assessment unreliable. Percentages have been rounded to the nearest whole number.

	Normal liver Stiffness (<1.35 m/s)	Abnormal liver Stiffness (≥ 1.35 m/s)	p value
N (%)	13 (48%)	14 (52%)
Baseline Information
Age (years)	14.9 +/− 14.8	20.8 +/− 14.3	0.30
Males (%)	4 (31%)	7 (50%)	0.53
History of HA	8 (62%)	7 (50%)	0.83
BMI Category			0.53
Healthy	6 (46%)	6 (43%)
Overweight or Obese	6 (46%)	8 (57%)
Underweight	1 (8%)	0 (0%)
UCD Diagnosis			0.37
OTC Deficiency	3 (23%)	6 (43%)
ASS1 Deficiency	3 (23%)	1 (7%)
ASL Deficiency	3 (23%)	5 (36%)
ARG1 Deficiency	4 (31%)	2 (14%)
Liver Biochemistries
ALT (units/L)	43 +/− 29	39 +/− 23	0.69
AST (units/L)	44 +/− 14	37 +/− 22	0.37
GGT (units/L)	20 +/− 11	22 +/− 19	0.76
Calculated Biomarkers
APRI	0.42 +/− 0.19	0.34 +/− 0.22	0.35
FIB-4	0.37 +/− 0.33	0.53 +/− 0.58	0.40
FibroTest™	0.18 +/− 0.12	0.18 +/− 0.16	0.98
ActiTest™	0.14 +/− 0.13	0.11 +/− 0.12	0.52
Ultrasonography
Abnormal Hepatic Parencyhma	5 (38 %)	7 (50%)	0.83

Abbreviations: ALT, alanine aminotransferase; APRI, AST to platelet ratio; ARG1, arginase; ASL, argininosuccinate lyase; ASS1, argininosuccinate synthase; AST, aspartate aminotransferase; BMI, body-mass index; GGT, gamma glutamyltransferase; HA, hyperammonemia; N, number; OTC, ornithine transcarbamylase;