Molecular analysis of contiguous exons of the phenylalanine hydroxylase gene: identification of a new PKU mutation

Quality control in the discovery, reporting, and recording of genomic variation

The usefulness of any database is dependent on the quality of its content. This is so for mutation databases and has been a continuing concern for those interested in such databases. This article discusses the critical points that determine the quality of the data, such as PCR errors, incomplete scanning, examination of the effect of the variation, and reporting and deposition of the mutations in a database. To illustrate the importance of quality control in mutation curation, nine articles reporting 34 novel phenylketonuria mutations were surveyed for the criteria believed to be important in describing mutations. Many articles were deficient in entries in several criteria, but there was still a high degree of certainty that the described mutations caused disease. Finally, strategies to eliminate errors and to enhance or indicate quality are discussed, including expression, the review process, checking deductions, and typing and encouraging compliance. Models for the future are also discussed.

Somatic mutation detection in human biomonitoring

Somatic cell gene mutation arising in vivo may be considered to be a biomarker for genotoxicity. Assays detecting mutations of the haemoglobin and glycophorin A genes in red blood cells and of the hypoxanthine-guanine phosphoribosyltransferase and human leucocyte antigenes in T-lymphocytes are available in humans. This MiniReview describes these assays and their application to studies of individuals exposed to genotoxic agents. Moreover, with the implementation of techniques of molecular biology mutation spectra can now be defined in addition to the quantitation of in vivo mutant frequencies. We describe current screening methods for unknown mutations, including the denaturing gradient gel electrophoresis, single strand conformation polymorphism analysis, heteroduplex analysis, chemical modification techniques and enzymatic cleavage methods. The advantage of mutation detection as a biomarker is that it integrates exposure and sensitivity in one measurement. With the analysis of mutation spectra it may thus be possible to identify the causative genotoxic agent.