Cardiac magnetic resonance imaging (MRI) was performed; dilated cardiomyopathy was diagnosed. Titration of optimal medical therapy was conducted. She was taking losartan 25 mg, bisoprolol 1.25 mg, and spironolactone 25 mg. The SGLT2 inhibitor was discontinued due to cystitis. The gene discussed is SLC5A2; the disease is chronic cystitis.