Living with Monomelic amyotrophy
A rare condition that causes weakness and muscle loss in one arm or hand, usually starting in the teen years or adulthood.
Understanding Monomelic amyotrophy
MMA affects lower motor neurons, the cells that carry signals from the brain to the muscles used for movement. It causes weakness and loss of muscle mass in the arms and fingers. It is most common in Asia, especially Japan and India, and males are more likely than females to develop it. Diagnosis is based on imaging and electromyography (EMG).
Signs & symptoms
Symptoms vary from person to person. GARD lists these among the most common:
- Muscle weakness in the arm or hand
- Loss of muscle mass in the arms and fingers
- Loss of nerve cells that control muscles (anterior horn cells)
- Muscle twitching
- Tremor
Not everyone has every symptom. GARD's list comes from the Human Phenotype Ontology.
Diagnosis
- 1Talk with your doctor
Share the symptoms you've noticed, when they started and your family health history. Notes and photos can help.
- 2See a specialist
Specialists who may be involved include brain and nervous system specialists.
- 3Ask which tests can help
Your care team will decide which exams and tests can confirm the diagnosis.
Care & treatment
- Care team
- Brain and nervous system specialists (neurologists)
- Expert care
- Ask about multidisciplinary care centers for rare conditions
- Treatment
- GARD doesn't list specific treatments for this condition. Your care team will tailor care to your symptoms.
- Research
- Clinical trials and observational studies may be options. See the research section below.
General information, not medical advice. Your care team makes the decisions.
Everyday life
Living with a rare condition is easier with support.
- Connect with rare disease patient organizations for support
- Keep notes on symptoms, changes and questions for appointments
- Ask about patient registries that help research
- Look into financial aid and travel resources for care visits
Quick facts
GARD says the exact cause is unknown. It can sometimes run in families, but it is not thought to be caused by a specific genetic change.
Also known as: benign focal amyotrophy; hirayama disease; jmadue; juvenile muscular atrophy of distal upper extremity; juvenile muscular atrophy of the distal upper limb
Patient organizations
Rare-disease groups that can help
- Global GenesRare Diseases · United States
- National Organization for Rare DisordersRare Diseases · United States
- Genetic AllianceRare Diseases · United States
- RARE FoundationRare Diseases · United States
You are more than your diagnosis
Perspectives from people navigating life with Monomelic amyotrophy.
Explore research for Monomelic amyotrophy
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