G10-G14: Systemic atrophies primarily affecting the central nervous system

G12: Spinal muscular atrophy and related syndromes

Spinal muscular atrophy and related syndromes, grouped under the ICD-10 code G12, are a class of genetic disorders characterized by the progressive loss of motor neurons in the spinal cord. This leads to skeletal muscle weakness and atrophy, causing difficulties in movement and, in severe cases, even respiratory issues. The severity and onset of symptoms vary within this group of conditions. While some forms of the disease, such as Werdnig-Hoffmann disease, begin in infancy and progress rapidly, other forms may not present until adulthood and progress slowly. All forms of this disease share a common mechanism - they are caused by a defect in the SMN1 gene, which is essential for the survival of motor neurons. These conditions are inherited in an autosomal recessive manner, meaning that an individual must inherit two copies of the defective gene—one from each parent—to develop the condition. It's also important to note that despite the muscle weakness, sensation and intellect remain unaffected in affected individuals.