Background: Brody myopathy is a rare autosomal recessive disorder caused by mutations in the ATP2A1 gene, which encodes for sarcoplasmic reticulum Ca++-ATPase (SERCA1) pump in the fast twitch skeletal muscle fibers.

Case presentation: Patient is a 19-year-old woman presenting with exercise-induced rhabdomyolysis. Genetic testing confirmed a pathologic ATP2A1 mutation affecting SERCA1 function in type 2 muscle fibers. The patient experienced significant functional limitations due to impaired calcium reuptake and prolonged muscle contraction.

Management and outcome: Treatment with dantrolene sodium resulted in marked clinical improvement. The patient demonstrated enhanced muscle relaxation, reduced exercise-induced stiffness, and improved functional capacity following dantrolene therapy.

Conclusion: This case demonstrates the therapeutic efficacy of dantrolene (off-label) in managing Brody myopathy symptoms. Given the rarity of this condition, further documentation of successful treatment strategies is crucial for establishing evidence-based management protocols for patients with ATP2A1-related myopathy.