Evaluate the Efficacy and Safety of Ruxolitinib on Hair Regrowth in Patients With Autoimmune Polyendocrinopathy Candidiasis Ectodermal Dystrophy (APECED)-Associated Alopecia Areata

Background: Autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED) is a problem of the immune system. In people with APECED, the immune system makes a mistake and attacks the body. Some people with APECED have a type of hair loss called alopecia areata (AA). No drugs are approved to treat AA. Objective: To see if a study drug (ruxolitinib) can help hair regrowth in people with APECED-associated AA and if it can improve other symptoms caused by the immune system s attack to the body. Eligibility: People aged 12 to 65 years with APECED and severe AA. Design: Participants will be in this study for up to 10 months. They will have 5 in-person visits and 6 televisits, each about 4 weeks apart. One in-person visit may be up to a 10-day stay in the hospital. The first in-person visit will include screening. Participants will have a physical exam. They will have blood tests. Photographs may be taken of their skin. They will answer questions about their quality of life. Participants will begin taking the study drug during their hospital stay. They will take the pills by mouth twice a day for 8 months. Researchers may take tissue samples from participants scalp, gums, and lower lip. Participants may provide samples of urine, stool, nail clippings, and saliva. They may have an eye exam and an ultrasound exam of their abdomen. Some tests may be repeated in subsequent in-person visits. In telehealth visits, participants will answer questions about how they are feeling. They will describe and send photos of hair regrowth. They will be asked to have blood drawn and the results sent to the researchers.