Iam hiQ-a novel pair of accuracy indices for imputed genotypes

Albert Rosenberger, Viola Tozzi, Heike Bickeböller, On behalf of INTEGRAL-ILCCO Consortium, Triantafillos Liloglou

Research output: Contribution to journalArticle (journal)peer-review

1 Citation (Scopus)
18 Downloads (Pure)


BACKGROUND: Imputation of untyped markers is a standard tool in genome-wide association studies to close the gap between directly genotyped and other known DNA variants. However, high accuracy with which genotypes are imputed is fundamental. Several accuracy measures have been proposed and some are implemented in imputation software, unfortunately diversely across platforms. In the present paper, we introduce Iam hiQ, an independent pair of accuracy measures that can be applied to dosage files, the output of all imputation software. Iam (imputation accuracy measure) quantifies the average amount of individual-specific versus population-specific genotype information in a linear manner. hiQ (heterogeneity in quantities of dosages) addresses the inter-individual heterogeneity between dosages of a marker across the sample at hand.

RESULTS: Applying both measures to a large case-control sample of the International Lung Cancer Consortium (ILCCO), comprising 27,065 individuals, we found meaningful thresholds for Iam and hiQ suitable to classify markers of poor accuracy. We demonstrate how Manhattan-like plots and moving averages of Iam and hiQ can be useful to identify regions enriched with less accurate imputed markers, whereas these regions would by missed when applying the accuracy measure info (implemented in IMPUTE2).

CONCLUSION: We recommend using Iam hiQ additional to other accuracy scores for variant filtering before stepping into the analysis of imputed GWAS data.

Original languageEnglish
Pages (from-to)50
JournalBMC Bioinformatics
Issue number1
Early online date24 Jan 2022
Publication statusPublished - 24 Jan 2022


  • Case-Control Studies
  • Genome-Wide Association Study
  • Genotype
  • Humans
  • Polymorphism, Single Nucleotide
  • Software


Dive into the research topics of 'Iam hiQ-a novel pair of accuracy indices for imputed genotypes'. Together they form a unique fingerprint.

Cite this