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Related Experiment Video

Updated: Apr 17, 2026

Detection of Rare Genomic Variants from Pooled Sequencing Using SPLINTER

Detection of Rare Genomic Variants from Pooled Sequencing Using SPLINTER

Published on: June 23, 2012

SNP imputation bias reduces effect size determination.

Pouya Khankhanian¹, Lennox Din¹, Stacy J Caillier¹

¹Department of Neurology, University of California San Francisco San Francisco, CA, USA.

Frontiers in Genetics

|February 25, 2015

Summary

This summary is machine-generated.

Choosing the right reference population for genetic imputation is crucial. Using healthy controls as a reference can introduce bias in genome-wide association studies (GWAS), especially for disease-associated markers.

Keywords:

SNP imputation genome-wide association study genomics haplotype estimation

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Area of Science:

Genetics
Bioinformatics
Computational Biology

Background:

Genotype imputation infers missing genetic data using reference panels.
Matching reference panel ethnicity to query data is standard practice.
The impact of reference panel phenotype on imputation accuracy is less understood.

Purpose of the Study:

To investigate imputation bias introduced by using reference populations with differing phenotypes.
To assess the effect of reference panel choice on genome-wide association study (GWAS) results.

Main Methods:

Imputed genotypes for disease-associated and non-associated markers in GWAS datasets for ALS, PD, and CD.
Compared imputation accuracy using healthy control references versus disease case references.
Evaluated imputation bias and its impact on effect sizes in simulated GWAS.

Main Results:

Using healthy controls as reference introduced significant imputation bias, particularly for disease-associated markers.
Using disease cases as reference attenuated this bias.
Imputation bias favored the non-risk allele and reduced the observed effect size (odds ratio) in GWAS.

Conclusions:

Imputation is valuable for genotype prediction and genetic risk estimation in GWAS.
A careful selection of the reference population phenotype is essential to minimize imputation bias.
The choice of reference panel significantly impacts the reliability of genetic association findings.