The entertainment world is mourning the loss of rising star Isabelle Tate, known for her appearance in the new spinoff “9-1-1: Nashville.” Tate passed away at just 23 years old, only days after the premiere of her first on-screen television role. Her talent agency confirmed that Isabelle had been living with a rare form of Charcot-Marie-Tooth disease, often called CMT — a genetic neurological disorder that affects the peripheral nerves in the arms and legs. But what exactly is Charcot-Marie-Toot