amyotrophic lateral sclerosis (ALS)


amyotrophic lateral sclerosis (ALS)

Degenerative nervous-system disorder causing muscle wasting and paralysis. The disease usually occurs after age 40, more often in men. Most victims die within two to five years from respiratory muscle atrophy. ALS affects motor neurons; the muscles they control become weak and atrophied, with debility usually beginning in the hands and creeping slowly up to the shoulders. The lower limbs become weak and spastic. Variants include progressive muscular atrophy and progressive bulbar palsy. In 1993 the defective gene that accounts for 5–10% of cases was discovered; it produces an ineffective version of an enzyme that neutralizes free radicals, which destroy motor neurons.

Variants of AMYOTROPHIC LATERAL SCLEROSIS (ALS)

amyotrophic lateral sclerosis (ALS) or Lou Gehrig disease

This entry comes from Encyclopædia Britannica Concise.
For the full entry on amyotrophic lateral sclerosis (ALS), visit Britannica.com.

Seen & Heard

What made you look up amyotrophic lateral sclerosis (ALS)? Please tell us what you were reading, watching or discussing that led you here.