Molecular temporal bone pathology: III. Genotyping of the deltaF508 deletion in the DNA of patients with cystic fibrosis

Deoxyribonucleic acid contamination in archival human temporal bones: a potentially significant problem

HYPOTHESIS

Contamination of archival human temporal bones with extraneous deoxyribonucleic acid may represent a potentially significant problem in the analysis of nucleic acids isolated from archival specimens.

BACKGROUND

During the past decade, there has been growing interest in the development of molecular biologic techniques that can be applied to the investigation of pathologic changes in archival human temporal bones. The impetus for the development of these techniques is in part related to the fact that the temporal bone collections represent a repository of archival material compiled over decades, which is not available from living patients.

METHODS

An archival human temporal bone specimen from a male patient with the Mohr-Tranebjaerg syndrome (formerly called DFN-1) and a well-characterized mutation was analyzed for the presence of the mutation by a standard method for extraction, isolation, amplification, and sequencing of deoxyribonucleic acid. The experiment was repeated four times.

RESULTS

The deoxyribonucleic acid sequence from three of four extractions was normal. The known mutation was easily and repeatedly demonstrated in a blood sample from the same individual. Because Mohr-Tranebjaerg syndrome is X-linked, there is only one allele, and therefore there is no potential endogenous source to account for the normal sequence that was amplified. Contamination of the tissue sections by extraneous deoxyribonucleic acid presumably occurred during acquisition and processing of the temporal bone.

CONCLUSIONS

Contamination of archival temporal bones with exogenous deoxyribonucleic acid is a significant potential problem that must be considered in the interpretation of the results of deoxyribonucleic acid retrieved from archival sections. The authors recommend collecting blood samples from temporal bone donors in the future to ensure the availability of a reliable source of deoxyribonucleic acid.