A 19-year-old female presents with fatigue for the past 3 months. She is of Ashkenazi Jewish origin. She reports a 2-year history of diarrhea accompanied by abdominal pain and cramping. Her stool is sometimes tinged with blood as well as mucus. She also has intermittent aches and malaise. Her stature is short relative to her parents. She smokes ½ a pack of cigarettes per day. On physical examination, the patient appears pale and thin. She has several, small painful sores inside her mouth. Her abdominal exam is unremarkable. Her legs demonstrate several red nodules that are tender to palpation. Anal exam reveals perianal skin tags. Her laboratory studies show a hemoglobin of 7.5 g/dL (normal 12–15.5 g/dL).