1 Genetic Studies of Urinary Metabolites Illuminate Mechanisms of Detoxification and 2 Excretion in Humans 3 4 Pascal Schlosser1*, Yong Li1*, Peggy Sekula1*, Johannes Raffler2, Franziska Grundner- 5 Culemann1, Maik Pietzner3,4, Yurong Cheng1, Matthias Wuttke1,5, Inga Steinbrenner1, Ulla T. 6 Schultheiss1,5, Fruzsina Kotsis1,5, Tim Kacprowski4,6,7, Lukas Forer8, Birgit Hausknecht9, Arif B. 7 Ekici10, Matthias Nauck3,4, Uwe Völker4,6, GCKD Investigators**, Gerd Walz5, Peter J. 8 Oefner11, Florian Kronenberg8, Robert P. Mohney12, Michael Köttgen5, Karsten Suhre13, Kai- 9 Uwe Eckardt9,14, Gabriele Kastenmüller2, Anna Köttgen1 10 11 * these authors contributed equally 12 ** a list of the GCKD Investigators is included in Supplementary Information 13 14 15 16 SUPPLEMENTARY INFORMATION 17
1
18 Table of Contents 19 20 SUPPLEMENTARY NOTE 1: SUPPLEMENTARY RESULTS ...... 3
21 INCORPORATION OF EXISTING BIOLOGICAL KNOWLEDGE INTO CAUSAL GENE ASSIGNMENT ...... 3
22 METABOLITE CLUSTERS PROVIDE BIOLOGICAL CONTEXT FOR YET UNNAMED METABOLITES ...... 4
23 METABOLITE RATIOS CAPTURE INSIGHTS INTO PHYSIOLOGY AND PHARMACOGENETICS ...... 6
24 ASSOCIATION BETWEEN NAT8-ASSOCIATED METABOLITES AND CKD PROGRESSION AND COMPLICATIONS ...... 7
25 SUPPLEMENTARY NOTE 2: EXTENDED ACKNOWLEDGEMENTS ...... 9
26 SUPPLEMENTARY FIGURE 1: OVERVIEW OF THE STUDY DESIGN ...... 10
27 SEPARATE FILE ATTACHED (60 PAGES): SF2_RAP.PDF ...... 11
28 SUPPLEMENTARY FIGURE 2: REGIONAL ASSOCIATION PLOTS FOR MQTLS IDENTIFIED IN MGWAS OF URINARY 29 METABOLITE CONCENTRATIONS ...... 11
30 SUPPLEMENTARY FIGURE 3: COMPARISON OF GENETIC EFFECTS WITH AND WITHOUT ADJUSTMENT FOR EGFR ...... 12
31 SUPPLEMENTARY FIGURE 4: EVALUATION OF GENETIC ASSOCIATIONS OF REPLICATED MQTLS FROM CKD PATIENTS IN 32 A HEALTHY POPULATION SAMPLE ...... 13
33 SUPPLEMENTARY FIGURE 5: CELL TYPE-SPECIFIC EXPRESSION OF ASSOCIATED GENES IN MURINE KIDNEY ...... 14
34 SUPPLEMENTARY FIGURE 6: ASSOCIATION BETWEEN THE INDEX SNP AT SLC7A9 AND PAIR-WISE METABOLITE RATIOS 35 REVEALS TRANSPORTED SUBSTRATES IN VIVO ...... 15
36 SUPPLEMENTARY FIGURE 7: OVERVIEW AND EXAMPLES OF METABOLITE CLUSTERING ...... 16
37 SUPPLEMENTARY FIGURE 8: CIRCULAR PRESENTATION OF GENETIC ASSOCIATIONS WITH EIGENMETABOLITES ...... 18
38 SUPPLEMENTARY FIGURE 9: IDENTIFICATION OF THE UNKNOWN METABOLITE X-13689 AS THE GLUCURONIDE OF 39 ALPHA-CMBHC ...... 19
40 SUPPLEMENTARY FIGURE 10: PRESENCE OF CO-LOCALIZING ASSOCIATION SIGNALS FOR URINARY METABOLITES AND 41 PHENOTYPES AND DISEASES IN THE UK BIOBANK ...... 20
42 REFERENCES:...... 21
43
2
44 Supplementary Note 1: Supplementary Results
45 46 Incorporation of existing biological knowledge into causal gene assignment 47 48 The workflow to assign potentially causal genes in GWAS loci was agnostic with respect to
49 existing biological and biochemical knowledge. Upon evaluation after the gene had been
50 assigned, the great majority of automatically assigned genes was also supported by existing
51 biochemical knowledge and experimental studies. There were a few instances, however, in
52 which incorporation of existing biochemical and biological knowledge into the causal gene
53 assignment process would have supported another gene in the locus (see Table). At these
54 loci, it may be that the automated gene assignment that was agnostic with respect to
55 existing biological and biochemical knowledge did not prioritize the correct causal gene. As
56 unbiased databases to facilitate automated gene assignment become more and more
57 complete, for example through the generation of gene expression data in additional tissues
58 and cell types, the assignment of the most likely gene in a given region may be subject to
59 change. Regardless, sensitivity analyses repeating all enrichment analyses with the use of
60 these genes instead of the automatically assigned ones at these eight loci yielded the same
61 or almost identical enriched pathways, tissues, and cell types (data not shown).
Automatically Biologically Associated known Background on biologically supported assigned gene in supported gene in metabolite(s) or gene locus (gene score) locus (gene score) module(s) CASP9 (hremc) AGMAT (hrem) 4-guanidinobutanoate, The enzyme encoded by AGMAT, beta- agmatinase, metabolizes N-(4- guanidinopropanoate aminobutyl)guanidine [http://www.hmdb.ca/] LRP8 (hep) CPT2 (h) methylsuccinoylcarnitine Succinoylcarnitine is a fatty acid. CPT2 encodes carnitine palmitoyltransferase II, which acts on fatty acids. ZKSCAN5 (he) CYP3A7 (NA) 16a-hydroxy DHEA 3- The enzyme encoded by CYP3A7 sulfate, andro steroid hydroxylates dehydroepiandrosterone monosulfate 3-sulphate. C19H28O6S (1)*, tauro- beta-muricholate PPP2R4 (hrem) CRAT (hre) 2- CRAT encodes carnitine O- methylmalonylcarnitine acetyltransferase. This enzyme (C4-DC) converts short- and medium-chain
3
acyl-CoAs, to which 2- methylmalonylcarnitine belongs. TRIM48 (NA) FOLH1 (NA) N-acetyl-aspartyl- FOLH1 encodes folate hydrolase 1, glutamate (NAAG) which metabolizes NAAG [PMID: 9622670]. The index SNP rs61898064 that gives rise to the automated assignment of TRIM48 is in LD (r2=0.798) with another mQTL (rs55728336). This other mQTL is associated with NAAG, and its index SNP was automatically assigned to FOLH1. The two signals were not merged because the r2 was not >0.8. NUPR1 (he), SULT1A2 (he) 3-hydroxyindolin-2-one The enzyme encoded by SULT1A2 CCDC101 (he) sulfate, furaneol sulfate catalyzes the sulfate conjugation of a wide variety of molecules. TYMS (ohre) ENOSF1 (ohe) ribonate The enzyme encoded by ENOSF1 plays a role in the catabolism of the deoxy sugar L-fucose. Ribonate is a sugar acid. CABP5 (e) SULT2A1 (e) androstenediol The encoded enzyme, (3beta,17beta) disulfate dehydroepiandrosterone (1) sulfotransferase, catalyzes the sulfation of steroids and bile acids including DHEA, of which androstenediol is a direct metabolite. BTN3A1 (hem) SLC17A1/A3/A4 (h) ME41 The metabolites assigned to this module belong to a substrate call transported by the SLC17A transporter family. The individually significant metabolite in the cluster, indolelactate, is assigned to SLC17A1/A3/A4. RAB11FIP5 (h) NAT8 (NA) ME160, ME161, ME166 All known metabolites assigned to the listed clusters are N-acetylated compounds. N-acetylation is a key function of the enzyme encoded by NAT8. 62
63 64 Metabolite clusters provide biological context for yet unnamed metabolites 65 66 Metabolites are intermediates of homeostatic reactions and as such inter-connected beyond
67 pair-wise relationships. Groups of correlated metabolites (“modules”) may reflect shared
68 biochemical pathways or co-regulation. We used a weighted gene co-expression analysis-
69 based approach, to construct 212 metabolite modules (Methods, Supplementary Figure 7A).
70 GWAS of the modules’ first principal component, the eigenmetabolite, identified 46
71 significant (P<2.3e-10 [5e-8/212]) and replicated associations between genetic variants and
4
72 38 unique metabolite modules (Supplementary Figure 8, Supplementary Table 12). In three
73 instances, the gene scored as most likely to be causal was not part of the 90 genes identified
74 in the single metabolite screen. One of them, CPT2, is also supported by biological evidence
75 but did not receive the highest score within the locus in the single metabolite screen (see
76 above). At the other four genes, biological evidence points toward a different gene than the
77 one automatically assigned (see above, Supplementary Table 12 + 15).
78 Eigenmetabolites that showed particularly strong genetic associations originated
79 from a module of five unknown metabolites (missense rs2147896 in PYROXD2, P=2.5e-917)
80 and a module composed of N2-acetyllysine, N-alpha-acetylornithine, X-12124, X-12125, and
81 X-15666 (missense rs13538 in NAT8, P=4.3e-635; Supplementary Figure 7B, C). Such
82 associations are suggestive of a common function of the enzyme on metabolites in the
83 module, implicating the unknown molecules in the NAT8-associated module as additional N-
84 acetylated compounds or their precursors. Similarly, a module of the known vitamin E
85 (tocopherol)-related metabolites also contained the two unknowns X-13689 and X-24359
86 (Supplementary Table 12) and was associated with rs55744319, which is in high LD with a
87 missense variant in CYP4F2, encoding p.Val433Met. This variant has previously been
88 identified in response to vitamin E supplementation1, vitamin E levels2, and warfarin
89 maintenance dose2,3. Investigation of the unknown metabolites based on their mass,
90 retention time, spectral information and genetic evidence nominated the unknown
91 molecules as structurally related to Vitamin E, with the glucuronide of alpha-CMBHC as a
92 candidate for X-13689. We experimentally verified this prediction through the examination
93 and comparison of retention times from ion chromatograms and the locations and
94 intensities of the MS/MS fragmentation spectra between a standard of the glucuronide of
95 alpha-CMBHC and X-13689 (Supplementary Figure 8). Thus, knowledge of an unknown’s
5
96 module membership and its genetic association can provide information beyond mass and
97 retention time by restricting the search space of their possible identity for experimental
98 verification.
99 While there were no genetic associations with modules that did not contain at least
100 one metabolite also identified by mGWAS, screening of eigenmetabolites provided the
101 important advantage of permitting a hypothesis-generating screen of higher order genetic
102 associations, whereas already the assessment of all pair-wise metabolite ratios would have
103 accumulated to 686,206 GWAS. Furthermore, 35 of 46 eigenmetabolite associations
104 implicate additional metabolites that were not identified in mGWAS after correction for
105 multiple testing (Supplementary Figure 8, Supplementary Table 12). We have made our
106 software, used for identification of eigenmetabolites, publicly available
107 (https://github.com/genepi-freiburg/Netboost), which may be of particular interest for
108 emerging large-scale integrative Omics efforts.
109
110 Metabolite ratios capture insights into physiology and pharmacogenetics 111 112 The renal tubular amino acid exchanger SLC7A9 is known to exchange dibasic amino acids
113 such as lysine from urine against intracellular neutral amino acids in model systems4,5. We
114 therefore screened all pair-wise metabolite ratios for this known exchanger. A p-gain
115 threshold of 6,728,320 (672,832*10) was used to identify ratios that contributed information
116 beyond their individual components, where 672,832 represents the number of tested ratios
117 (1172*1171/2) after exclusion of ratios with less than 300 measurements. The index SNP
118 rs12460876, associated with differential SLC7A9 expression (Supplementary Table 3), was
119 related to 83 informative metabolite ratios (P-gain >6.7e6, Supplementary Figure 6). Of
120 these, all ratios that contained lysine also contained neutral amino acids such as
6
121 phenylalanine, threonine, glutamine, or alanine, reflecting its known physiological function,
122 amino acid exchange at the apical membrane of tubular epithelial cells4. In this screen, 5-
123 hydroxy-lysine and the unknown metabolite X-24736 emerged as novel candidate substrates
124 of this exchanger (Supplementary Figure 6). Based on spectral information, mass and
125 retention time, X-24736 is likely an arginine-containing metabolite, consistent with the
126 uptake of dibasic amino acids from urine. The identification of novel candidate substrates of
127 known transport proteins is of high interest for pharmaceutical research, both with respect
128 to a target’s therapeutic potential but also to anticipate potential side effects.
129
130 Association between NAT8-associated metabolites and CKD progression and complications
131 Given the high and near-exclusive expression of NAT8 in kidney, we tested whether the 30
132 NAT8-associated metabolites may carry information about the risk of CKD progression and
133 CKD-related endpoints complementary to eGFR, for example by capturing detoxification
134 capacity. N-acetylation is an important reaction in a major route of detoxification, the
135 generation of water-soluble mercapturic acids6. Spearman correlation coefficients of the 30
136 metabolites with eGFR, the main measure of kidney function in clinical practice, were weak
137 (range -0.17 to 0.24). We assessed the association of the NAT8-associated metabolites with
138 incident end-stage kidney disease (ESKD, n=61), incident major cardiovascular events (MACE,
139 n=143) and all-cause mortality (n=129; Methods). In comparison to a model with clinical
140 information alone, inclusion of metabolites significantly improved the model fit for ESKD
141 (P=1.5e-4, Methods, Supplementary Table 14). While higher urinary concentrations of X-
142 13698 and N-acetylglutamine were protective (HR=0.59 for both), N-acetylkynurenine, N-
143 acetylcitrulline, N-delta-acetylornithine and X-12125 were associated with higher risk (HR
144 range: 1.17-1.47). These metabolites therefore represent potential new biomarkers of ESKD,
7
145 along with altered N-acetylation capacity as an implicated mechanism, for evaluation in
146 larger studies of CKD progression.
8
147 Supplementary Note 2: Extended acknowledgements
148 List of GCKD Study Investigators
149 A list of nephrologists currently collaborating with the GCKD study is available at 150 http://www.gckd.org. 151 University of Erlangen-Nürnberg Kai-Uwe Eckardt, Heike Meiselbach, Markus Schneider, Thomas Dienemann, Hans-Ulrich Prokosch, Barbara Bärthlein, Andreas Beck, Thomas Ganslandt, André Reis, Arif B. Ekici, Susanne Avendaño, Dinah Becker-Grosspitsch, Ulrike Alberth- Schmidt, Birgit Hausknecht, Rita Zitzmann, Anke Weigel
University of Freiburg Gerd Walz, Anna Köttgen, Ulla Schultheiß, Fruzsina Kotsis, Simone Meder, Erna Mitsch, Ursula Reinhard
RWTH Aachen University Jürgen Floege, Georg Schlieper, Turgay Saritas, Sabine Ernst, Nicole Beaujean
Charité, University Medicine Berlin Elke Schaeffner, Seema Baid-Agrawal, Kerstin Theisen
Hannover Medical School Hermann Haller, Jan Menne
University of Heidelberg Martin Zeier, Claudia Sommerer, Rebecca Woitke
University of Jena Gunter Wolf, Martin Busch, Rainer Fuß
Ludwig-Maximilians University of München Thomas Sitter, Claudia Blank
University of Würzburg Christoph Wanner, Vera Krane, Antje Börner-Klein, Britta Bauer
Medical University of Innsbruck, Division of Florian Kronenberg, Julia Raschenberger, Barbara Genetic Epidemiology Kollerits, Lukas Forer, Sebastian Schönherr, Hansi Weissensteiner
University of Regensburg, Institute of Peter Oefner, Wolfram Gronwald, Helena Zacharias Functional Genomics Department of Medical Biometry, Informatics Matthias Schmid, Jennifer Nadal and Epidemiology (IMBIE), University of Bonn 152 153
9
154 Supplementary Figure 1: Overview of the study design
A B
155 156 Schematic representation of the genome-wide screens for single metabolites (A) and 157 eigenmetabolites (B) and their follow up analyses. 158 159
10
160 Separate file attached (60 pages): SF2_RAP.pdf
161
162 Supplementary Figure 2: Regional association plots for mQTLs identified in mGWAS of 163 urinary metabolite concentrations
164 165 For each of the 240 mQTLs, the region for plotting was selected as the outer borders of 166 merged overlapping 1-Mb windows. The extended MHC region was treated as one region. 167 The index SNP with the lowest p-value is indicated. The metabolite giving rise to the 168 association is included in the title. Linkage disequilibrium information, used to color-code 169 correlation with the index SNP, was calculated from the analyzed subsample of the GCKD 170 study. 171
11
● 2
●● ● ●
● ● ●●
1 ● ● ●● ●● ●●● ●●●●● ●● ●●● ●●●● ●●● ●● ●●● ●●●● ●●● ●●● ● 0 ●● ●●● ●●● ●●● ●●● ●●● ●●● ●● ●●● ●● ●●● ● ●● ● ● ●● − 1 ●● ● ● ●
residualized for genetic PCs + age sex for residualized ● ●● ● ●
− 2 ●
●
−2 −1 0 1 2
172 Residualized for genetic PCs + age + sex + ln(eGFR) + ln(UACR) 173 Supplementary Figure 3: Comparison of genetic effects with and without adjustment for 174 eGFR
175 Each point represents one of the 240 replicated metabolite-associated mQTLs. Genetic 176 effect size estimates per modeled risk allele including adjustment for eGFR and UACR (X- 177 axis), as done in the main analysis, were plotted against those obtained after adjustment 178 for genetic PCs, age and sex only (Y-axis).
12
A B 2 2
● ● ● ● 1 1 ● ● ● ●● ● ● ● ●● ● ●● ●● ● ● ●● ● ●● ● ● ●● ● ● ●● ●● ● ● ●● ● ● ● ● ● ● ● ● ●● ● ●● ● ●●● ● ●●● ● ● ● ● ● ●●● ● ●●● ● ● ● ●●● ●●● ● 0 0 ●● ● ●● ● ●●● ●●● ● ●●● ● ●●● ● ●●● ● ● ●●● ● ● ●● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●
● ● ● ● ● ● 1 1
− ● − ● Effect size in Healthy Population in Healthy size Effect Population in Healthy size Effect
●
● −log10(p−value) = 11 ● −log10(p−value) = 12
2 ● −log10(p−value) = 309 2 ● −log10(p−value) = 309 − −
−2 −1 0 1 2 −2 −1 0 1 2
Effect size in GCKD Effect size in GCKD
C D 2 2
● ● ● ● 1 1 ● ● ● ●● ● ●● ● ●● ● ●● ●● ●● ● ●● ● ●● ● ● ●● ● ● ●● ●● ● ● ●● ● ● ● ● ● ● ● ● ●● ● ●● ● ●●● ● ●●● ● ● ● ● ● ●●● ● ●●● ● ● ● ●●● ●●● ● ● 0 0 ●● ●● ●● ●● ●●● ●●● ● ●●● ● ●●● ● ●●● ● ● ●●● ● ● ●● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● −log10(p−value) = 11 ● ● ● ● ● ● ● −log10(p−value) = 309 ● ● ● ● ● ● ● 1 1 Amino Acid
− ● − ● ● −log10(p−value) = 11 ● Unknown Effect size in Healthy Population in Healthy size Effect Population in Healthy size Effect ● ● −log10(p−value) = 309 ● ● Lipid ● LC/MS Pos Early ● Nucleotide ● LC/MS Neg ● Xenobiotics
2 ● LC/MS Polar 2 ● other − −
−2 −1 0 1 2 −2 −1 0 1 2
Effect size in GCKD Effect size in GCKD
E F 2 2
● ● ● ● 1 1 ● ● ● ●● ● ●● ● ●● ● ●● ●● ●● ● ●● ● ●● ● ● ●● ● ● ●● ●● ● ● ●● ● ● ● ● ● ● ● ● ●● ● ●● ● ●●● ● ●●● ● ● ● ● ● ●●● ● ●●● ● ● ● ●●● ●●● ● ● 0 0 ●● ●● ●● ●● ●●● ●●● ● ●●● ● ●●● ● ●●● ● ● ●●● ● ● ●● ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●
● ● ● ● ● ● ● 1 −log10(p−value) = 11 1
− ● − ● ● −log10(p−value) = 309 ● −log10(p−value) = 11 Effect size in Healthy Population in Healthy size Effect Population in Healthy size Effect ● ● RSD GCKD − RSD SHIP >0.08 ● ● −log10(p−value) = 309 ● RSD GCKD − RSD SHIP <−0.08 ● 0< % imputed values GCKD <7 ● abs(RSD GCKD − RSD SHIP) <0.08 ● 7< % imputed values GCKD <22
2 ● NA 2 ● 22< % imputed values GCKD − −
−2 −1 0 1 2 −2 −1 0 1 2
Effect size in GCKD Effect size in GCKD
179 Supplementary Figure 4: Evaluation of genetic associations of replicated mQTLs from CKD 180 patients in a healthy population sample
181 (A) Each point represents the index SNP of one of 90 associations that could be matched 182 between the Metabolon platforms of the GCKD and SHIP-trend studies. Dot size is 183 proportional to the -log10(P-value) in GCKD and crosses represent 1.96x standard errors in 184 each study. The red line corresponds to a linear regression based on the effect estimates 185 of the most significant index SNP in each of the 35 unique genetic regions into which the 186 90 associations map. (B) 81 mQTLs with -log10(P-value) > 12 are plotted. In subsequent 187 panels, the color codes correspond to the detection mode of the mass spectrometer (C), 188 metabolite super pathway (D), differences in relative standard deviation based on 189 measurements of duplicate samples as a measure of precision (E), and the percent of 190 imputed values in GCKD (F). For strata with at least 10 matched mQTLs, additional regression 191 lines were added. 192
13
193 A B murine kidney cells CYP4A11 (Cyp4a32) EC RPS6KA2 (Rps6ka2) Podocyte ACOT2 (Acot2) PT NAT8 (Nat8) CYP2D6 (Cyp2d10) LOH ACY3 (Acy3) DCT ACOX1 (Acox1) CD Trans DHTKD1 (Dhtkd1) PC SLC17A1 (Slc17a1) IC DPEP1 (Dpep1) Fibroblast CYP2C8 (Cyp2j5) Macrophage ACSM2A (Acsm2) Neutrophil SLC7A9 (Slc7a9) B lymphocyte AACS (Aacs) SLC5A9 (Slc5a9) T lymphocyte GGT1 (Ggt1) NK DECR2 (Decr2) novel1 GLDC (Gldc) novel2 PYROXD2 (Pyroxd2) 02468 FMO4 (Fmo4) log (P value) 10 ACOT4 (Acot4) AOC1 (Aoc1) CYP2C8 (Cyp2j7) NAALAD2 (Naalad2) ACOT2 (Acot3) GSTM2 (Gstm7) GOT2 (Got2) ADH1A (Adh1) SULT2A1 (Sult2a3) PAOX (Paox) BST1 (Bst1) HDAC10 (Hdac10) SLC28A2 (Gm14085) ACOT2 (Acot1) FOLH1 (Folh1) CYP4A11 (Cyp4a31) AFMID (Afmid) ACADL (Acadl) IC PT EC PC NK Z-score DCT LOH Trans novel1 novel2 Podocyte Fibroblast CD Neutrophil Macrophage T lymphocyte B lymphocyte 20 2 194 195 Supplementary Figure 5: Cell type-specific expression of associated genes in murine kidney
196 (A): Enrichment testing showed that associated genes are highly expressed in cells of the 197 proximal tubule in mice. The vertical line indicates the statistical significance threshold after 198 Bonferroni adjustment; the arrow indicates p-value <1e-8. (B): Heatmap illustrates the 199 relative expression of each associated genes across the murine kidney cell types; only genes 200 with z-score >2 in at least one cell type are plotted. The mouse gene homologs are provided 201 in parentheses. EC: endothelial cells; PT: proximal tubule; LOH: loop of Henle; DCT: distal 202 convoluted tubule; PC: principal cells; IC: Intercalated cells; CD-Trans: collecting duct 203 transient cells; NK: natural killer cells.
14
204 205 Supplementary Figure 6: Association between the index SNP at SLC7A9 and pair-wise 206 metabolite ratios reveals transported substrates in vivo
207 The figure uses color-coding to show the strength of associations (test statistics scaled to [- 208 1,1]) between genotype and the 83 ratios that contained information beyond the 209 associations of their individual components (P-gain>6,728,320, Methods), based on 210 association analysis of 672,832 pair-wise metabolite ratios (1172*1171/2, excl. 13,374 ratios 211 with <300 measurements). Test statistics of results that did not confer additional 212 information (P-gain≤6,728,320) are uniformly presented in gray. The metabolite on the Y- 213 axis represents the numerator and on the X-axis the denominator of the respective ratio. 214 Super-pathways: 01 amino acid, 02 carbohydrate, 04 energy, 05 lipid, 06 nucleotide, 08 215 peptide, 09 unknown. Metabolites that are a member of more than four associated 216 metabolite ratios with a scaled test statistic >0.5 (absolute) are marked in bold. The T allele 217 at rs12460876 was associated with higher gene expression, in agreement with greater 218 tubular reuptake of lysine, resulting in lower urinary levels. 219
15
A Height 0.0 0.2 0.4 0.6 0.8 1.0
B C 0.06
0.03
rs2147896
0.00 AA AG ME193 GG