This study will define the major genetic risk and protective factors for idiopathic inflammatory myopathies (IIM), a group of immune disorders affecting connective tissues such as muscles. It will also identify new environmental risk factors for IIM and identify immune responses in myositis and related diseases. There are many forms of IIMs, and the causes of these diseases are unknown. However, scientists suspect that they result when people with some genetic factors that predispose them-that is, put them at greater risk-are exposed to certain environmental triggers. Some of those triggers include food, drugs, biologics (such as a vaccine to prevent disease), medical devices and occupational exposures.

Patients, including children under 18, who had a diagnosis of myositis, a related autoimmune disease, or a rheumatic disease, as well as their blood relatives, and control subjects who were in good health have already been recruited for this study.

The evaluation consisted of one outpatient visit to the patient's doctor, who will obtain a medical history and conduct a physician examination. Patients spent 20 to 30 minutes to answer written questions. There was a blood collection of about 6 tablespoons. If there was a major change in patients' medical conditions, they were asked to return for a second outpatient evaluation to determine whether any of the blood tests or antibodies, which show an immune response, had changed. Blood samples collected will be used only for laboratory research studies. The samples have been identified by a code, and all other identifying information have been removed.

During the study, researchers will explore possible environmental risk factors, including studies of infectious and non-infectious agents. They will analyze the blood for genetic markers and test for certain antibodies. Laboratory results will be evaluated as they relate to the signs, symptoms, and severity of patients' illnesses. That would help researchers to better understand patterns of the diseases and the outcomes for patients.

This study will not have a direct benefit for patients. However, results from the study can be made available to patients' doctors for use in appropriate care. Also, it is hoped that information gained can help other people in the future.