It started with a slight twitch. Steve and Gay Grossman both noticed it in their daughter Lilly in 1998, when she was just one-and-a-half years old. By the time she was four, the twitches had grown into full-blown muscle tremors. They wracked her whole body at night and were painful enough to wake her up.

The family stopped sleeping properly. Lilly would wake up, shaking and crying, as often as 20 or 30 times a night. During the worst bouts, Steve and Gay took shifts to console her, one staying with her until two in the morning and the other taking over from there. “I can’t describe what it’s like to care for a baby, a young child, who’s crying and