what is motor neuron disease caused by
A brief description of the symptoms of some of the more common MNDs follows. Amyotrophic lateral sclerosis (ALS), also called Lou Gehrig's disease or classical motor neuron disease, is a progressive, ultimately fatal disorder that disrupts signals to all voluntary muscles.pinal muscular atrophy (SMA) is a hereditary disease affecting the lower motor neurons. It is an autosomal recessive disorder caused by defects in the gene SMN1, which makes a protein that is important for the survival of motor neurons (SMN protein).