Types of Muscular Dystrophy and Neuromuscular Diseases Muscular dystrophy is a group of inherited diseases that are characterized by weakness and wasting away of muscle tissue, with or without the breakdown of nerve tissue. Muscular Dystrophy Muscular dystrophy causes the muscles in the body to become very weak. The muscles break down and are replaced with fatty deposits over time. Amyotrophic Lateral Sclerosis (ALS) Amyotrophic lateral sclerosis is a neurological disorder marked by the progressive degeneration of nerve cells in the spinal cord and brain. It is often referred to as Lou Gehrig’s disease, after a famous baseball player who died from it. Lambert-Eaton Syndrome Lambert-Eaton Syndrome, also known as Lambert-Eaton Myasthenic Syndrome, occurs when your immune system attacks the neuromuscular junction—the area where your nerves and muscles connect. Myasthenia Gravis Myasthenia gravis (MG) is an autoimmune disorder that causes weakness of the skeletal muscles. MG affects the voluntary muscles of the body, especially the eyes, mouth, throat, and limbs. Polymyositis Polymyositis is a disease that causes the skeletal muscles—the muscles that allow your body to move—to become irritated and inflamed.