The symptoms of MMA usually progress slowly for two to five years and then remain stable for many years. The weakness can progress to the opposite limb, although whether this progression is typical or rare is under discussion. Cases of patient improvement and deterioration have both been described, but are atypical. Initially MMA can be confused for slowly progressing case of other neurological diseases such as amyotrophic lateral sclerosis (ALS); initial symptoms can be similar, but their causes are apparently different, and their outcomes markedly so. Diagnostic tools have improved since first described, and a few therapies are being introduced. But sometimes several years of observation are needed before a definitive diagnosis can be made. Use of a cervical collar may afford relief, and some researchers advocate its therapeutic use. There is also a slowly progressive variant of MMA known as O'Sullivan-McLeod syndrome, which only affects the small muscles of the hand and forearm and has a slowly progressive course.
Monomelic amyotrophy
Congenital distal spinal muscular atrophy
Chondrodystrophy
Spinal muscular atrophy with lower extremity predominance 1
Hereditary neuralgic amyotrophy
Spinal muscular atrophy
Congenital muscular dystrophy
Spinal and bulbar muscular atrophy