Table 1.
Principal components analysis in GENECARD
| Factors | Metabolites within factora | Overall description of factor | Eigenvalue | Total var | Cum var | Heritability (SD) | P-value |
|---|---|---|---|---|---|---|---|
| 1 | C2, C6-DC, C8, C8:1, C10, C10:1, C10:3, C10-OH:C8-DC, C12, C12:1, C14, C14:1, C14:2, C14:1-OH, C14-OH:C12-DC | Short- and medium-chain acylcarnitines | 11.88 | 0.20 | 0.20 | 0.39 (0.16) | 0.0006 |
| 2 | Total FFA, FA-C14:0, FA-C16:0, FA-C16:1, FA-C18:0, FA-C18:1, FA-C18:2, FA-C18:3 | Free fatty acids | 7.55 | 0.13 | 0.32 | 0.35 (0.20) | 0.02 |
| 3 | ARG, GLX, ORN, C16, C18, C18:1, C18:2 | Amino acids, long-chain acylcarnitines (markers of overall mitochondrial function) | 5.89 | 0.10 | 0.42 | 0.40 (0.18) | 0.002 |
| 4 | C2, C4-OH, C14:1, C14:2, C14:1-OH, Ket, Hbut | FFA oxidation by-products | 3.51 | 0.06 | 0.48 | 0.61 (0.17) | 0.00004 |
| 5 | ALA, LEU/ILE, MET, PRO, TYR, VAL, PHE, C5, C3, C20 | Metabolites involved in amino-acid catabolism | 2.98 | 0.05 | 0.53 | 0.27 (0.15) | 0.01 |
| 6 | CIT, C5-DC, C8:1, C10:3 | Various | 2.36 | 0.04 | 0.57 | 0.51 (0.17) | 0.0008 |
| 7 | SER, GLY, CIT, MET | Amino acids | 2.04 | 0.03 | 0.60 | 0.44 (0.28) | 0.09 |
| 8 | C14-OH:C12-DC, C18:1-OH, C22 | Various | 1.89 | 0.03 | 0.64 | 0.40 (0.18) | 0.003 |
| 9 | C12-OH:C10-DC, C14, C14:1-OH, C20 | Various | 1.86 | 0.03 | 0.67 | 0.51 (0.17) | 0.0003 |
| 10 | C3, C4:Ci4, C22 | Various | 1.67 | 0.03 | 0.69 | 0.46 (0.19) | 0.002 |
| 11 | ASX, HIS | Amino acids | 1.48 | 0.02 | 0.72 | 0.33 (0.17) | 0.005 |
| 12 | FAC22:6, FAC20:4, C20 | Long-chain free fatty acids | 1.37 | 0.02 | 0.74 | 0.36 (0.17) | 0.007 |
| 13 | C16-OH:C14-DC | Various | 1.24 | 0.02 | 0.76 | 0.46 (0.20) | 0.002 |
| 14 | PRO, ALA, C18:1-DC | Various | 1.18 | 0.02 | 0.78 | 0.54 (0.16) | 0.0001 |
| 15 | C18-DC:C20-OH | Various | 1.06 | 0.02 | 0.80 | 0.45 (0.19) | 0.006 |
FFA, free fatty acids; tot var, total variance; cum var, cumulative variance.
Results of PCA in the data set are presented, including the key metabolites within each factor (i.e. those with a factor load ⩾∣0.4∣); an overall biochemical description of the key metabolites within each factor; and the eigenvalue, total and cumulative variance, heritability and P-value for the heritability point estimate for each factor.
Factor load ⩾∣0.4∣.