Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Spinal Muscular Atrophy (SMA) is a neuromuscular disease characterized by degeneration of motor neurons, resulting in progressive muscular atrophy (wasting away) and weakness. The clinical spectrum of SMA ranges from early infant death to normal adult life with only mild weakness. These patients often require comprehensive medical care involving multiple disciplines, including pediatric pulmonology, pediatric neurology, pediatric orthopedic surgery, pediatric critical care, and physical medicine and rehabilitation; and physical therapy, occupational therapy, respiratory therapy, and clinical nutrition. Genetic counseling is also helpful for the parents and family members. The term "juvenile spinal muscular atrophy" refers to Kugelberg-Welander syndrome.