Hypometric genetics: Improved power in genetic discovery by incorporating quality control flags

Y. Tanigawa and M. Kellis. Am J Hum Genet. (2024).

Graphical abstract

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Abstract

Balancing the tradeoff between quantity and quality of phenotypic data is critical in omics studies. Measurements below the limit of quantification (BLQ) are often tagged in quality control fields, but these flags are currently underutilized in human genetics studies. Extreme phenotype sampling is advantageous for mapping rare variant effects. We hypothesize that genetic drivers, along with environmental and technical factors, contribute to the presence of BLQ flags. Here, we introduce "hypometric genetics" (hMG) analysis and uncover a genetic basis for BLQ flags, indicating an additional source of genetic signal for genetic discovery, especially from phenotypic extremes. Applying our hMG approach to n=227,469 UK Biobank individuals with metabolomic profiles, we reveal more than 5% heritability for BLQ flags and report biologically relevant associations, for example, at APOC3, APOA5, and PDE3B loci. For common variants, polygenic scores trained only for BLQ flags predict the corresponding quantitative traits with 91% accuracy, validating the genetic basis. For rare coding variant associations, we find an asymmetric 65.4% higher enrichment of metabolite-lowering associations for BLQ flags, highlighting the impact of putative loss-of-function variants with large effects on phenotypic extremes. Joint analysis of binarized BLQ flags and the corresponding quantitative metabolite measurements improves power in Bayesian rare variant aggregation tests, resulting in an average of 181% more prioritized genes. Our approach is broadly applicable to -omics profiling. Overall, our results underscore the benefit of integrating quality control flags and quantitative measurements and highlight the advantage of joint analysis of population-based samples and phenotypic extremes in human genetics studies.

Browseable phenotypes

Here, we display available inclusive PGS models in UK Biobank. You can use the sorting and filtering functions. For example, you may enter ">30000" in the '# variants' column to select iPGS models with more than 30,000 genetic variants.

Trait type Trait #variants Parent field ID Heritability
Trait type Trait #variants Parent field ID Heritability
Original (incl. BLQ measurements)Phospholipids in Chylomicrons and Extremely Large VLDL12757234830.1302
Truncated (excl. BLQ measurements)Truncated: Phospholipids in Chylomicrons and Extremely Large VLDL6361234830.0907
BLQ (binarized at BLQ threshold)Below the limit of quantification: Phospholipids in Chylomicrons and Extremely Large VLDL6112234830.0698
Derived (percentage traits, incl. BLQ measurements)Phospholipids to Total Lipids in Chylomicrons and Extremely Large VLDL percentage4781234830.0548
Derived (percentage traits, excl. BLQ measurements)Phospholipids to Total Lipids in Chylomicrons and Extremely Large VLDL percentage (BLQ-flagged measurement removed)3398234830.0301
BLQ (derived)Below the limit of quantification: Phospholipids to Total Lipids in Chylomicrons and Extremely Large VLDL percentage, QC Flag3584234830.0556
Original (incl. BLQ measurements)Cholesteryl Esters in Chylomicrons and Extremely Large VLDL13158234850.1322
Truncated (excl. BLQ measurements)Truncated: Cholesteryl Esters in Chylomicrons and Extremely Large VLDL6945234850.0951
BLQ (binarized at BLQ threshold)Below the limit of quantification: Cholesteryl Esters in Chylomicrons and Extremely Large VLDL3397234850.0656
Derived (percentage traits, incl. BLQ measurements)Cholesteryl Esters to Total Lipids in Chylomicrons and Extremely Large VLDL percentage2636234850.0348
Derived (percentage traits, excl. BLQ measurements)Cholesteryl Esters to Total Lipids in Chylomicrons and Extremely Large VLDL percentage (BLQ-flagged measurement removed)3276234850.0445
BLQ (derived)Below the limit of quantification: Cholesteryl Esters to Total Lipids in Chylomicrons and Extremely Large VLDL percentage, QC Flag2675234850.0523
Original (incl. BLQ measurements)Free Cholesterol in Chylomicrons and Extremely Large VLDL12817234860.1303
Truncated (excl. BLQ measurements)Truncated: Free Cholesterol in Chylomicrons and Extremely Large VLDL4551234860.088
BLQ (binarized at BLQ threshold)Below the limit of quantification: Free Cholesterol in Chylomicrons and Extremely Large VLDL5219234860.0714
Derived (percentage traits, incl. BLQ measurements)Free Cholesterol to Total Lipids in Chylomicrons and Extremely Large VLDL percentage3252234860.0383
Derived (percentage traits, excl. BLQ measurements)Free Cholesterol to Total Lipids in Chylomicrons and Extremely Large VLDL percentage (BLQ-flagged measurement removed)2707234860.0549
BLQ (derived)Below the limit of quantification: Free Cholesterol to Total Lipids in Chylomicrons and Extremely Large VLDL percentage, QC Flag3467234860.0554
Original (incl. BLQ measurements)Phospholipids in Very Large VLDL14190234900.1405
Truncated (excl. BLQ measurements)Truncated: Phospholipids in Very Large VLDL10058234900.1106
BLQ (binarized at BLQ threshold)Below the limit of quantification: Phospholipids in Very Large VLDL4450234900.0528
Derived (percentage traits, incl. BLQ measurements)Phospholipids to Total Lipids in Very Large VLDL percentage4867234900.045
Derived (percentage traits, excl. BLQ measurements)Phospholipids to Total Lipids in Very Large VLDL percentage (BLQ-flagged measurement removed)3564234900.0564
BLQ (derived)Below the limit of quantification: Phospholipids to Total Lipids in Very Large VLDL percentage, QC Flag2771234900.0471
Original (incl. BLQ measurements)Free Cholesterol in Very Large VLDL13572234930.1381
Truncated (excl. BLQ measurements)Truncated: Free Cholesterol in Very Large VLDL7910234930.1002
BLQ (binarized at BLQ threshold)Below the limit of quantification: Free Cholesterol in Very Large VLDL4794234930.0604
Derived (percentage traits, incl. BLQ measurements)Free Cholesterol to Total Lipids in Very Large VLDL percentage9009234930.0959
Derived (percentage traits, excl. BLQ measurements)Free Cholesterol to Total Lipids in Very Large VLDL percentage (BLQ-flagged measurement removed)8003234930.1148
BLQ (derived)Below the limit of quantification: Free Cholesterol to Total Lipids in Very Large VLDL percentage, QC Flag3395234930.0536

Predictive performance

You can also browse the predictive performance on the held-out test set in UK Biobank.

Data download

  • For each phenotype listed above, you can download the coefficients of the iPGS models using the "download" button on each page.
  • The coefficients of the PGS models analyzed in the study are available at the Open Science Framerowk (doi: 10.17605/OSF.IO/CEB7G), suitable for bulk downloading of the iPGS models across multiple traits.

References