MSFinals-2400

A 54-year-old woman presents to the rheumatology clinic with a history of her fingers turning white, blue, and red intermittently for the past four months. She also reports tightness of the skin on her fingers, hands, and face, without involvement of the skin on her upper arm or chest. Additionally, she experiences troubling reflux symptoms. On examination, there is fibrotic skin overlying the hands and face with telangiectasia. Which autoantibody is most likely to be positive in this patient, given the probable diagnosis?