Postmortem CYP2D6 Genotyping and Copy Number Determinations Using DNA Extracted from Archived FTA Bloodstains

: Genetic characterization of CYP2D6 post-mortem may help explain drug involvement in cause of death. Here we describe methods for DNA extraction, CYP2D6 genotyping and copy number variation (CNV) testing using dried blood archived at autopsy with FTA® cards. Bloodstained cards (n=75) were obtained from the Utah Office of the Medical Examiner. DNA was extracted from 3mm punches; DNA yield was 9-100 ng/μL; the 260/280 ratio was 1.2-2.0. CYP2D6 alleles detected using the iPLEX® genotyping assay and MassARRAY (Agena Bioscience) include (n=) *2A (20), *3 (2), *4 (26), *5(3), *6 (2), *10 (1), *29 (1), *35 (9) and*41 (10). CYP2D6 genotype could not be determined in one sample that failed to amplify. More than two copies of CYP2D6 were detected in 11 samples. CNV could not be determined in six samples. The commercially available methods described here were successful for CYP2D6 testing of post-mortem blood samples archived with FTA® cards.