Precision of High-Throughput Single-Nucleotide Polymorphism Genotyping with Fingernail DNA: Comparison with Blood DNA

Recently, high-throughput single-nucleotide polymorphism (SNP) genotyping arrays have been used for genome-wide association study. Blood samples are commonly used for such analyses because they provide genomic DNA of high molecular weight and in high quantities. Blood sampling is often difficult, however, when patients are located a great distance from the laboratory and the sample requires careful handling for transportation. Instead, buccal swabs or urinary epithelial cells have been used as noninvasive sources of DNA(1). Fingernail clippings are also obtained noninvasively and more easily. Such samples need no special attention for transportation and can be preserved dry at room temperature for long periods; however, because fingernail clippings yield fragmented DNA that may be contaminated with certain PCR inhibitors(2), this sample type has seemed unsuitable for analyses requiring high-quality genomic DNA. In this study, we compared the precision of Affymetrix GeneChip™ array-based SNP genotyping with fingernail DNA vs blood DNA and demonstrated the usefulness of fingernail DNA in genotyping and genome copy-number analysis.