The purpose of this research registry is to gather information about clinical symptoms and laboratory test results in patients with undifferentiated connective tissue disease (UCTD). Analysis of this information may help to better predict the prognosis for patients with this form of autoimmune disease, and may identify risk factors for progression to more specific connective tissue diseases such as systemic lupus. This is done by collecting information from your medical records including clinical history, physical examination, and lab test results, and by asking you questions about specific symptoms you may have such as joint pain, rashes, and other common symptoms of UCTD. This information will be stored in a database, and used at a later time for research studies. All future research studies using information in this registry will be subject to oversight by HSS's Institutional Review Board (which is responsible for oversight of research at HSS involving human subjects). All patients who seek or receive medical care at HSS for undifferentiated connective tissue disease will be invited to participate in this registry.