Apparent human BRCAI knockout caused by mispriming during polymerase chainreaction: Implications for genetic testing

We report an apparent BRCA I homozygous knockout that, on further analysis. was found to be an artefact of the polymerase chain reaction. This finding has two important implications. First, it challenges results of a previous study that reported a homozygous knockout associated with the same BRCA I mutation. Second, our findings suggest that mispriming caused by mismatched primers at the site of single-nucleotide polymorphisms, leading to prefere ntial amplification of one allele, may represent a significant proportion o f instances of mutation-detection insensitivity. This may have major implic ations for the sensitivity of all polymerase chain reaction-based mutation- detection methods in clinical genetic testing laboratories. (C) 2001 Wiley- Liss, Inc.