Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by the degeneration and death of both upper and lower motor neurons in the brain, brainstem, and spinal cord, leading to muscle weakness, atrophy, fasciculations, spasticity, and ultimately fatal paralysis. The disease typically manifests in middle adulthood, with about 10% of cases being familial and linked to genetic mutations such as those in the SOD1 gene. ALS exhibits clinical and genetic heterogeneity, with subtypes defined by inheritance patterns, age of onset, and associated conditions like frontotemporal dementia, though no distinct "type 1" classification is recognized in current literature. Pathological features include neuronal loss, intracellular protein aggregates, and specific inclusions in surviving motor neurons. The etiology is multifactorial, involving complex interactions between genetic susceptibility and environmental factors.