Malignant Hyperthermia (MH) is a pharmacogenetic disorder characterized by a hypermetabolic skeletal muscle response to volatile anesthetics. While there are hundreds of mutations in the Ryanodine Receptor 1 gene (RyR1) associated with MH, the current diagnostic protocol has only confirmed 35 mutations to be causative. This study aims to develop a more efficient method for validating mutations. The CRISPR/Cas9 system has emerged as an efficient and targetable gene-editing tool used to assist in homology-driven repair (HDR) for the insertion of donor templates in vitro. Serine integrase site-specific recombination offers a more efficient method of gene editing but requires specific recognition sites. In this study, we use CRISPR/Cas9 and Dual Integrase Cassette Exchange (DICE) to create RyR1-mutant cell lines. Using calcium imaging, myotubes consisting of differentiated myoblasts are tested for their sensitivity to the calcium-releasing triggers KCl, caffeine, and 4-chloro-m-cresol. The sensitivities of RyR1-mutant myotubes are compared to wild-type myotubes. An increase in sensitivity is indicative of MH and is used to classify the mutations as likely causative. The study is performed on primary murine myoblasts that have been immortalized via lentiviral transduction of cyclin-dependent kinase 4 (CDK4). We have designed and tested guide RNAs (gRNAs) used in the CRISPR/Cas9 system, identifying three gRNAs with DNA-cleavage efficiencies of 25-30%. The combined use of CRISPR/Cas9 and DICE allows for the efficient and rapid creation of RyR1-mutant cell lines in which the mutations can subsequently be functionally validated. In doing so, we hope to expedite the validation of MH-associated mutations for the purpose of assisting the development of a genetic screen. In addition, our methods can be applied to other regions of the genome to create an improved, high-throughput method of genomic engineering.