Progressive muscular atrophy (PMA), also called Duchenne–Aran disease and Duchenne–Aran muscular atrophy, is a disorder characterised by the degeneration of lower motor neurons, resulting in generalised, progressive loss of muscle function. PMA is classified among motor neuron diseases (MND) where it is thought to account for around 4% of all MND cases.PMA affects only the lower motor neurons, in contrast to amyotrophic lateral sclerosis (ALS), the most common MND, which affects both the upper and lower motor neurons, or primary lateral sclerosis, another MND, which affects only the upper motor neurons. The distinction is important because PMA is associated with a better prognosis than ALS. Signs and symptoms
As a result of lower motor neuron degeneration, the symptoms of PMA include:
muscle weakness
muscle atrophy
fasciculationsSome patients have symptoms restricted only to the arms or legs (or in some cases just one of either). These cases are referred to as flail limb (either flail arm or flail leg) and are associated with a better prognosis. Diagnosis
PMA is a diagnosis of exclusion, there is no specific test which can conclusively establish whether a patient has the condition. Instead, a number of other possibilities have to be ruled out, such as multifocal motor neuropathy or spinal muscular atrophy. Tests used in the diagnostic process include MRI, clinical examination, and EMG.
In the United States the most common terms are ALS (both specifically for ALS and as a blanket term) or Lou Gehrigs disease. Notable cases
Isaac W. Sprague - Entertainer and sideshow performer, billed as "the living human skeleton". Mike Gregory - Former Great Britain rugby league captain and head coach at Wigan RLFC
Rob Rensenbrink - Former Netherlands and Anderlecht football player

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