Also known as Amyotrophic lateral sclerosis, it is a condition or a form of motor neuron disease arising because of the degeneration of nerve cells in the brain and spinal cord that control voluntary muscle movement. The cause behind this disease is unknown but in 10% of the cases it is due to genetic disorder. Symptoms generally appear after the age of 50, and they include loss of muscle strength and coordination which may create trouble in going up steps, getting out of a chair, or swallowing. First symptoms initiate with the arms or legs. There is no cure, but a medicine called riluzole slows down the growth of the disease.