Isabelle Tate's cause of death has been revealed. The 9-1-1: Nashville actress passed away on October 19 at just 23 years old, her talent agency, McCray Agency, heartbreakingly shared on Wednesday. The rising star had been candid about being diagnosed with a progressive neuromuscular disease when she was just 13. In a follow-up statement, the agency shared more details, explaining Isabelle died of "a rare form of Charcot-Marie-Tooth disease.