Chronic progressive wasting of the skeletal muscles as a clinical observation has claimed the attention and interest of neurologic observers for many years. The underlying cause is a subject regarding which opinions have varied considerably from time to time. Since the christening of the disease by Aran, several types have been withdrawn from the original group, leaving a small and comparatively rare entity to which the name progressive muscular atrophy may still appropriately be applied.
Several clinical conditions in which muscular atrophy occurred as an incidental accompaniment rather than as a primary dominant characteristic—such as syringomyelia and unusual or aberrant forms of disseminated sclerosis—were withdrawn from this classification and, later, the subacute and chronic forms of poliomyelitis, the primary myopathies and some of the chronic or toxic forms of peripheral neuritis were eliminated, leaving the original term to represent what may now be regarded as an exceedingly rare disease.
MOLEEN GA. FAMILIAL PROGRESSIVE MUSCULAR ATROPHY. Arch NeurPsych. 1932;27(3):645-660. doi:10.1001/archneurpsyc.1932.02230150161008