Table 4. Analysis of both determined AGXT2 SNPs with regard to plasma (in µmol/L) and urinary (in µmol/g creatinine) BAIB concentrations.

Plasma BAIB	AGXT2 rs16899974	AGXT2 rs37369
		WT (c.418 GG)	Hetero (c.418 GA)	Homo (c.418 AA)
	WT (c.1492 GG)	0.92 (0.74–1.13); n = 218	1.43 (1.12–1.83); n = 20	2.51; n = 1	p<0.001
	Hetero (c.1492 GT)	1.05 (0.86–1.29); n = 114	1.55 (1.16–1.83); n = 22	2.31 (1.63–2.78); n = 3	p<0.001
	Homo (c.1492 TT)	1.08 (0.90–1.60); n = 13	2.03 (1.67–2.39); n = 4	/	p = 0.011
		p<0.001	p = 0.172	n.d.
Urinary BAIB	AGXT2 rs16899974	AGXT2 rs37369
		WT (c.418 GG)	Hetero (c.418 GA)	Homo (c.418 AA)
	WT (c.1492 GG)	44.1 (27.9–67.9); n = 218	151 (83.1–230); n = 20	1036; n = 1	p<0.001
	Hetero (c.1492 GT)	58.5 (38.6–89.1); n = 116	167 (76.9–251); n = 24	689 (309–1316); n = 3	p<0.001
	Homo (c.1492 TT)	111 (51.1–140); n = 13	374 (292–587); n = 5	/	p<0.001
		p<0.001	p = 0.042	n.d.

Median values (25–75% percentile) are shown. Both SNPs were significant for plasma and urinary BAIB in two-way ANOVA models using log-transformed data. The p values in the last rows and lower columns are based on nested ANOVA tests of log-transformed data (significant if p<0.025).

AGXT2, alanine-glyoxylate aminotransferase 2; BAIB, β-aminoisobutyrate; Hetero, heterozygous for minor allele; Homo, homozygous for minor allele; n.d., not determined; WT (wild-type), homozygous for major allele.