Final answer:
ALS, or amyotrophic lateral sclerosis, is a progressive neurodegenerative disease that affects the neurons responsible for controlling voluntary muscle movement. The disease causes muscle weakness, coordination problems, and paralysis. Genetic factors, including mutations in genes like SOD1, can contribute to the development of ALS.
Step-by-step explanation:
ALS, or amyotrophic lateral sclerosis, is a progressive neurodegenerative disease that affects the neurons responsible for controlling voluntary muscle movement. The disease causes the degeneration of these neurons, leading to muscle weakness, coordination problems, and eventually paralysis. The symptoms of ALS can vary from person to person, but common symptoms include muscle weakness, cramps, twitching, difficulty speaking and swallowing, and eventually respiratory failure.
ALS is caused by a combination of genetic and environmental factors. In familial cases of ALS, about 20% of cases are caused by mutations in the SOD1 gene. Other genetic mutations have also been associated with ALS, but in many cases, the underlying molecular pathology is not yet known. Sporadic cases of ALS, which account for the majority of cases, do not have target mutations but may be influenced by environmental factors.
In terms of genetics, there is no specific number of genes needed for ALS to occur. ALS is a complex disease with multiple genetic factors involved. While mutations in certain genes, such as SOD1, can increase the risk of developing ALS, there are also other genetic and environmental factors that can contribute to the disease.