While ALS is the most common motor neuron disease, we also treat all other forms, including: 1  PLS (Primary Lateral Sclerosis), affecting the upper motor neurons in the brain and spinal cord. 2  PMA (Primary Muscular Atrophy), affecting the lower motor neurons from the spine to the muscle.
Deletion Mutation and DNA. A deletion mutation occurs when part of a DNA molecule is not copied during DNA replication. This uncopied part can be as small as a single nucleotide or as much as an entire chromosome.The loss of this DNA during replication can lead to a genetic disease.eletion Mutation and DNA. A deletion mutation occurs when part of a DNA molecule is not copied during DNA replication. This uncopied part can be as small as a single nucleotide or as much as an entire chromosome.
About 95% of people with SMA have a deletion mutation in both copies of the SMN1 gene. This is called a homozygous deletion. The other 5% of people with SMA have a âpoint mutation â. This is when a single base (nucleotide) within the DNA is altered. Often they will have the more common deletion mutation in one of their copies of SMN1, and the point mutation in the other copy.