Overview
Progressive encephalomyelitis with rigidity and myoclonus, often called PERM, is a rare neurological condition that affects the brain and spinal cord. It is closely related to stiff person syndrome but is generally more severe. In PERM, the immune system mistakenly attacks parts of the nervous system, leading to widespread inflammation in the brain (encephalitis) and spinal cord (myelitis). This causes increasing muscle stiffness (rigidity), sudden involuntary muscle jerks (myoclonus), and painful muscle spasms. Over time, patients may also develop difficulty walking, problems with eye movements, trouble swallowing, and issues with balance. Some people experience confusion, memory problems, or other changes in brain function. PERM is considered an autoimmune disorder, meaning the body's own immune system is the cause. Many patients have antibodies against specific proteins in the nervous system, most commonly antibodies against glycine receptors (GlyR antibodies) or glutamic acid decarboxylase (GAD antibodies). These antibodies interfere with normal nerve signaling, which leads to the characteristic stiffness and spasms. Treatment focuses on calming the immune system and managing symptoms. Immunotherapy — including corticosteroids, intravenous immunoglobulin (IVIG), and plasma exchange — is the main approach. Medications to reduce muscle stiffness and spasms, such as benzodiazepines and baclofen, are also commonly used. Early diagnosis and treatment can improve outcomes, but the disease can be life-threatening if not recognized and treated promptly. Some patients respond well to immunotherapy and experience significant improvement, while others may have a more progressive course.
Also known as:
Key symptoms:
Severe muscle stiffness throughout the bodySudden involuntary muscle jerks (myoclonus)Painful muscle spasms triggered by noise, touch, or movementDifficulty walking or inability to walkProblems with balance and coordinationDifficulty swallowingAbnormal eye movementsSlurred speechConfusion or changes in thinkingExaggerated startle responseBreathing difficultiesAutonomic problems such as sweating, rapid heart rate, or blood pressure changesSensory symptoms like numbness or tinglingAnxiety or fear related to spasms
Sporadic
Usually appears on its own, not inherited from a parent
Adult
Begins in adulthood (age 18 or older)
FDA & Trial Timeline
1 eventUniversity of California, San Francisco — PHASE1, PHASE2
Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.
Treatments
No FDA-approved treatments are currently listed for Progressive encephalomyelitis with rigidity and myoclonus.
View clinical trials →Clinical Trials
View all trials with filters →No actively recruiting trials found for Progressive encephalomyelitis with rigidity and myoclonus at this time.
New trials open frequently. Follow this disease to get notified.
Specialists
View all specialists →No specialists are currently listed for Progressive encephalomyelitis with rigidity and myoclonus.
Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Travel Grants
No travel grants are currently matched to Progressive encephalomyelitis with rigidity and myoclonus.
Community
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Start the conversation →Latest news about Progressive encephalomyelitis with rigidity and myoclonus
Disease timeline:
New recruiting trial: Examining a Novel Gastrointestinal Intervention to Negate Environmental Toxicants (ENGINE)
A new clinical trial is recruiting patients for Progressive encephalomyelitis with rigidity and myoclonus
Caregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
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Family & Caregiver Grants
Financial assistance programs specifically for caregivers of rare disease patients.
Social Security Disability
Learn how rare disease patients may qualify for SSDI/SSI benefits.
Questions for your doctor
Bring these to your next appointment
- Q1.What type of antibodies were found in my tests, and how does that affect my treatment plan?,Should I be screened for an underlying cancer that could be causing this condition?,What immunotherapy options are available, and what are the risks and benefits of each?,How will we know if the treatment is working, and how often will I need follow-up testing?,What should I do if I experience a sudden worsening of stiffness or breathing difficulty?,Will I need long-term immunosuppressive treatment, and what are the side effects?,Are there clinical trials or specialized centers for this condition that I should consider?
Common questions about Progressive encephalomyelitis with rigidity and myoclonus
What is Progressive encephalomyelitis with rigidity and myoclonus?
Progressive encephalomyelitis with rigidity and myoclonus, often called PERM, is a rare neurological condition that affects the brain and spinal cord. It is closely related to stiff person syndrome but is generally more severe. In PERM, the immune system mistakenly attacks parts of the nervous system, leading to widespread inflammation in the brain (encephalitis) and spinal cord (myelitis). This causes increasing muscle stiffness (rigidity), sudden involuntary muscle jerks (myoclonus), and painful muscle spasms. Over time, patients may also develop difficulty walking, problems with eye movemen
How is Progressive encephalomyelitis with rigidity and myoclonus inherited?
Progressive encephalomyelitis with rigidity and myoclonus follows a sporadic inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Progressive encephalomyelitis with rigidity and myoclonus typically begin?
Typical onset of Progressive encephalomyelitis with rigidity and myoclonus is adult. Age of onset can vary across affected individuals.