Discrepant DNA analysis in three patients with inherited arrhythmia: molecular genetic test results deserve a second...

Molecular results provide a basis for diagnosis, risk assessment, medical management and genetic counseling. Unlike other areas of laboratory medicine, molecular genetic tests are rarely repeated. We describe three patients with suspected inherited arrhythmia in whom genetic testing was arranged via clinical and/or research laboratories. In all three instances, initial test results appeared falsely negative, with no deleterious mutations detected by various methodologies in selected long-QT or catecholaminergic polymorphic ventricular tachycardia-related genes. Discordant results emerged upon repeat analysis in separate laboratories. The cases highlight the importance of clinical judgment and assessment of genetic test results and methodology, in addition to the role of re-testing in molecular genetic medicine, particularly in the case of uninformative negative results.