Chitin is also found in the cell walls of certain fungi and algae. Biology chitin definition of by the free dictionarycollins english dictionary. It is a primary component of cell walls in fungi, the exoskeletons chitine, which was derived 1821 from greek word (chiton), meaning covering although you may have never heard it, chitin abundant nature.
Amyotrophic lateral sclerosis (ALS) is a progressive neurological disease that causes muscle weakness and gradually impacts on the functioning of the body, leading to eventual death. It is also referred to as motor neuron disease or Lou Gehrig's disease, named after the famous baseball player who had the condition.
However, these genetic causes are only responsible for about 10% of cases (Familial ALS). 90% of cases (Sporadic ALS) have no known cause. As a previous answer said, there may be a combination of factors, both genetic and environmental, which trigger the disease in the majority of patients.