Objective:

To collect information and biospecimens (such as blood, muscle, and skin samples) that will be used to research causes and treatments of inflammatory muscle diseases.

Eligibility:

People aged 2 years and older with suspected or confirmed inflammatory muscle disease. Healthy volunteers aged 18 years and older are also needed.

Design:

Participants will have at least 1 clinic visit. Each visit will last 4 to 8 hours. Some may return for additional visits.

All participants will undergo these procedures (unless they are unable to):

• Physical exam, including blood and urine tests.
• Magnetic resonance imaging (MRI) scan of the thigh. Participants will lie still on a table with padding around 1 thigh. The table will slide into a tube. The scan will last for approximately 40 minutes.

Some procedures are optional:

• Muscle biopsy: An area of skin will be numbed. A quarter-inch cut will be made. Several pieces of muscle tissue, about the size of grains of rice, will be removed.
• Skin biopsy: An area of skin will be numbed. A piece of skin about a quarter inch in diameter will be removed.
• Lymph node biopsy: A small sample of fluid or tissue from a lymph node will taken to check for infection.
• Genetic testing. Some of the samples collected may be used for genetic testing.

Study Description:

This is an observational study to characterize the different types of inflammatory myopathies, understand their etiology, pathogenesis, prognosis, and response to different treatments.

Objectives:

Primary objective: Define the different types of inflammatory muscle diseases, their etiology, pathogenesis, prognostic factors, and response to different treatments.

Secondary objectives: Study different diagnostic modalities that may help to diagnose and monitor the evolution of the disease in patients with myositis.

Endpoints:

Primary endpoint: Severity of muscle, skin, pulmonary, and joint involvement. Study of the immune dysregulation, transcriptomic changes, and genetic modifications in patients with inflammatory muscle diseases.

Secondary endpoints: Utility of standard of care laboratory, radiologic, electrophysiologic, and clinical studies to diagnose and monitor the evolution of the disease in patients with myositis.

• INCLUSION CRITERIA:

In order to be eligible to participate in this study, an individual must meet all of the following criteria:

1. Ability of subject, or Legally Authorized Representative (LAR) to understand and the willingness to sign a written informed consent and/or assent document.

2a. Patients are adults and minors of age 2 or older, with possible inflammatory myopathy (suspected or confirmed)

OR

2b. Healthy volunteers will be adults aged 18 or older.

EXCLUSION CRITERIA:

1. Unwilling to participate in research studies or to provide research samples or data.

Patients with possible inflammatory muscle disease (suspected or confirmed), and healthy volunteers.