Home > Encyclopedia of Neurological Disorders > Monomelic Amyotrophy

Definition

Monomelic amyotrophy (MMA) is a rare disease of the nerves that control voluntary movements of the limbs.

Description

One of the motor neuron diseases (MND), degenerative conditions that involve the nerves of the upper or lower parts of the body, MMA is generally a benign disease associated with minimal disability. Onset of MMA primarily occurs between the ages of 15 and 25. The main features of the disease are wasting and weakness of a single upper or lower limb. Generally, MMA progresses slowly overa period of 2–4 years, and then reaches a stationary phase during which the disease remains stable for years.

Monomelic amyotrophy may also be known as benign focal amyotrophy, single limb atrophy, Hirayama syndrome or Sobue disease. Descriptive terms such as brachial monomelic amyotrophy (MMA confined to...