Actress’ Worst Fear: Does She Have Huntington’s Disease?

Filmmaker Lucy Walker, who received Oscar nominations for “Waste Land” (2010) and “The Tsunami and the Cherry Blossom (2011), follows Marianna Palka as she prepares to go to the doctor and open the envelope that will seal her fate. Her short documentary, “The Lion’s Mouth Opens,” premieres at the Sundance Film Festival Jan. 18.