Progressive muscular atrophy is a motor neuron disease characterized by progressive degeneration of anterior horn (front portion of spinal cord) cells.

The cause of the condition is unknown. A familial form of the condition has been described with autosomal dominant inheritance.

The condition is characterized by muscular weakness and muscular atrophy. There is evidence of anterior horn cell dysfunction (front portion of spinal cord), with muscle wasting and marked weakness. The muscle wasting and weakness begin in the hands and progress to the arms, shoulders, and legs; eventually becoming generalized. The site of onset is random and progression is asymmetric. Fasciculations may be the earliest sign.

Factors related to the diagnosis include the times of life during which the onset of the condition occurs (middle or late adult life), and the progressive generalized motor involvement without sensory abnormalities. A biopsy of the muscles may be done. Electromyography is done.

No specific treatment is known. An anticholinergic may be used to decrease saliva production. Treatment may also include physical therapy to help maintain muscle function and orthopedic devices such as braces or a walker may be used to improve mobility.

Residuals will include progressive muscle wasting and weakness. There may be progressive difficulty in breathing and swallowing, and eventually respiratory complications, leading to death, may be possible outcomes.

• May be entitled to special monthly compensation where the Veteran has a single service-connected disability rated as 100% with additional service-connected disability or disabilities independently ratable at 60% or more, which are separate and distinct from the 100% service-connected disability and involves different anatomical segments or bodily systems. See  38 CFR 3.350(i)(1) – Special Monthly Compensation (SMC)

• Progressive muscular atrophy refers to progressive spinal muscular atrophy, which is a disease of the spinal cord. This disease shall be granted service connection although not otherwise established as incurred in or aggravated by service if manifested to a compensable degree within the applicable time limits under 38 CFR 3.307 following service in a period of war or following peacetime service on or after January 1, 1947, provided the rebuttable presumption provisions of 38 CFR 3.307 are also satisfied [38 CFR 38 CFR 3.309 .  [Disease subject to presumptive service connection], 38 CFR 3.309(a) [chronic disease].

• It is required for the minimum ratings for residuals under diagnostic codes 8000-8025, that there be ascertainable residuals. Determinations as to the presence of residuals not capable of objective verification, i.e., headaches, dizziness, fatigability, must be approached on the basis of the diagnosis recorded; subjective residuals will be accepted when consistent with the disease and not more likely attributable to other disease or no disease. It is of exceptional importance that when ratings in excess of the prescribed minimum ratings are assigned, the diagnostic codes utilized as bases of evaluation be cited, in addition to the codes identifying the diagnoses.