DNA technology in the clinical laboratory - Overview

Objectives.--To review the advances in clinically useful molecular biologic al techniques and to identify their applications in clinical practice, as p resented at the Eighth Annual William Beaumont Hospital Symposium. Data Sources.--The 10 manuscripts submitted were reviewed, and their major findings were compared with literature on the same topic. Study Selection.--Two manuscripts addressed specimen (nucleic acid) stabili ty, 2 described novel analytic approaches, 3 discussed detection of B- or T -cell clonality in lymphoproliferative disorders, and 3 reported the freque ncy of a variety of genetic polymorphisms found in cardiac disorders. Data Synthesis.--DNA from dried blood spots is stable and may be purified r apidly for amplification and mutation analysis. RNA is much less stable, an d a variety of methods may be used to reduce ribonuclease degradation of en teroviral RNA. False-negative reactions may be reduced by genomic amplifica tion of ligated padlock probes by cascade rolling circle or polymerase chai n reaction. A multiplex polymerase chain method using fluorescence-labeled products that separate both the wild-type and mutant hemochromatosis gene a lleles by capillary gel electrophoresis represents another approach for det ecting the 2 major missense mutations (C282Y and H63D) in hemochromatosis. Southern blotting and polymerase chain reaction have been used to detect B- and T-cell clonality in lymphoproliferative diseases, including mantle cel l lymphoma and lymphoma of the breast. Genetic polymorphisms in a variety o f coagulation factors and platelet glycoprotein IIIa are associated with is chemic heart disease. Conclusions.--As the Human Genome Project continues to define disease-assoc iated mutations, the number of clinically useful molecular pathologic techn iques and assays will expand. Clinical outcome analysis is still required t o document a decrease in the patient's length of stay to offset the cost of introducing molecular biological assays in the routine clinical pathology laboratory.