Clinical, Molecular and Imaging Biomarkers in Spinal and Bulbar Muscular Atrophy (SBMA)

Background: SBMA is an inherited chronic disease. It affects males in mid to late adulthood. It causes slowly progressive weakness of muscles and hand tremors. Researchers want to learn more about the effects of SBMA. Objective: To identify measurements that change over time in SBMA, including tests of muscle strength and function, as well as measurements of muscle and fat size. Eligibility: Men over the age of 18 both with and without a history of SBMA. Design: Participants will have a medical history, physical exam, and blood and urine tests. They will have neuromuscular ultrasound. They will have a lumbar puncture to obtain spinal fluid. For this, a needle will be inserted into the spinal canal in the lower back. Participants will have muscle strength and function tests. These tests may include pushing, pulling, rising from a chair and sitting back down, and/or walking. During these tests, they may wear an accelerometer (activity tracker) on their wrist. Participants will get an activity tracker to wear on their wrist for 10 days at home every 3 months. Participants with SBMA will also have lower limb magnetic resonance imaging (MRI) and optional whole-body MRI. They will have lung function tests. They will have speech and swallow tests. They will complete questionnaires. They may have optional body scans to measure bone density and lean body mass. They may have optional muscle biopsies. For biopsies, a needle will be used to take a small piece of muscle from the leg. Participants with SBMA will have 5 study visits over 2 years (every 6 months). Participants without SBMA will have 1 study visit.