Validity of Maternal Genotypes in DNA from Archival Pregnancy Serum Samples

Abstract

Much functional genomic research has focused on genotypic data from large cohorts or entire populations(1). The large population-based serum biobanks collected for maternal (pregnancy) screening and stored in many countries could be useful for genetic epidemiologic studies if DNA extracted from archival serum and plasma is of sufficient quantity and quality for successful genotyping analyses(2)(3)(4). Serum collected during pregnancy also contains cell-free DNA from the fetus(5), however, which might affect the outcome of genotyping analyses. We have evaluated the concordance of genotypes between DNA extracted from archival maternal sera with DNA from fresh whole blood from the same women. The median DNA yield was 15 mg/L (range 1–34 mg/L) using QiaAmp DNA minipreps (Qiagen) on 200 μL fresh whole blood from 137 women and 90 μg/L (range 0–4800 μg/L) using the MagNA Pure LC and Total Nucleic Acid Isolation Kit (MagNAPure; Roche Diagnostics) on 200 μL of 191 archival maternal sera from the same women. DNA yield decreased with increasing serum sample age ( P = 0.005, Jonckheere–Terpstra) (Fig. 1⇓ ), with no difference due to first- or second-trimester sampling ( P = 0.616, …