B-221 Combined RT-PCR and Whole Exome Sequencing Pharmacogenetic Testing in Polypharmacy Patient: A Case Report

• Published in: Clinical chemistry (Baltimore, Md.) Vol. 70; no. Supplement_1
• Main Authors: Rubio Prieto, J L, Segura, E, Pérez López, E, Cordero Matia, E, Rodríguez Rodríguez, A, García de Veas Silva, J, Guerrero, J, Macher, H
• Format: Journal Article
• Language: English
• Published: 02.10.2024
• ISSN: 0009-9147; 1530-8561
• DOI: 10.1093/clinchem/hvae106.581

Abstract Background Pharmacogenetics has become one of the main branches of Precision Medicine owing to its usefulness for patients’s optimal therapeutic management. Notwithstanding, pharmacogenetic testing results must be taken carefully, specially in multimorbidity patients with a variety of drugs prescribed. The aim of the present work is to introduce a combined RT-PCR and Whole Exome Sequencing Approach for pharmacogenetic testing in a patient with multiple drug-related adverse events. Case Background A 67 years old female was derived to our Clinical Chemistry Unit for pharmacogenetic testing due to multiple drug-related adverse events: nifedipine-voriconazole interaction, voriconazole-related neurological toxicity and moxifloxacin-related dizziness. Aditionally, she had been receiving morphine, corticoid for her reumatoid arthritis and antituberculous therapy (r isoniazid / pyrazinamide / rifampin and ethambutol). Methods Patient’s DNA was extracted from a blood sample and undergone by pharmacogenetic testing in two parallel ways: -A first genotyping assay was carried out using Taqman® OpenArray™ PGx Express 120 panel (ThermoFisher™), according to manufacturer’s instructions. -Simultaneusly, in order to cover possible copy number variants and SNPs not covered by our RT-PCR array, a whole exome sequencing run was performed on IlluminaTM NextSeq 1000. Sample library was prepared applying a custom GRCh38 pipeline. Results Relevant variants related to patient’s therapy found by RT-PCR are shown in table 1. SNPs genotyped by RT-PCR were confirmed by NGS. Moreover, whole exome sequencing revealed a deletion in exon 5 of SLCO1B1 gene, which corresponds to SLCO1B1*49 (loss of function); and some variants in NAT2 that may cause toxicity in antituberculous treatment (diplotype NAT2*6C/*7C). Conclusions In those challenging cases that involve multimorbidity and polypharmacy patients, pharmacogenetic testing must be approached taking into account variants that are not covered by the analytical method routinely used and the possibility of complement it with alternative proccedures.