Overview
Autosomal dominant adult-onset proximal spinal muscular atrophy (also known as adult-onset proximal SMA or late-onset SMA type 4) is a rare neuromuscular disorder characterized by progressive degeneration of the lower motor neurons in the spinal cord. Unlike the more common childhood-onset forms of spinal muscular atrophy, this condition manifests in adulthood, typically after the age of 30, and follows an autosomal dominant inheritance pattern rather than the autosomal recessive pattern seen in classical SMA caused by SMN1 mutations. The disease primarily affects the motor neurons that control voluntary muscles, particularly those closest to the trunk of the body (proximal muscles). Patients typically present with slowly progressive, symmetric weakness and wasting of the proximal limb muscles, especially in the legs and hip girdle region. Symptoms may include difficulty climbing stairs, rising from a seated position, and walking. Fasciculations (muscle twitching) and muscle cramps may also be observed. Deep tendon reflexes are often reduced or absent. The disease generally progresses slowly, and most affected individuals retain the ability to walk for many years, though some may eventually require mobility aids. There is currently no cure or disease-modifying treatment specifically approved for this form of SMA. Management is primarily supportive and symptomatic, including physical therapy to maintain muscle strength and mobility, occupational therapy, and orthopedic interventions as needed. The therapies approved for SMN1-related SMA (such as nusinersen, onasemnogene abeparvovec, and risdiplam) are not indicated for this genetically distinct condition. Regular monitoring by a multidisciplinary team including neurologists and rehabilitation specialists is recommended to optimize quality of life.
Also known as:
Clinical phenotype terms— hover any for plain English:
Autosomal dominant
Passed on from just one parent; each child has about a 50% chance of inheriting it
Adult
Begins in adulthood (age 18 or older)
FDA & Trial Timeline
10 eventsMallory Hacker — NA
Biogen — PHASE3
Novartis Pharmaceuticals — PHASE4
Biogen — PHASE3
Anas El Fathi — NA
The Hong Kong Polytechnic University — NA
Danish Research Centre for Magnetic Resonance — NA
MarsiBionics — NA
Scholar Rock, Inc. — PHASE2
Institut de Myologie, France
Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.
Treatments
No FDA-approved treatments are currently listed for Autosomal dominant adult-onset proximal spinal muscular atrophy.
14 clinical trialsare actively recruiting — trials can provide access to cutting-edge therapies.
View clinical trials →Rare Disease Specialist
Rare Disease Specialist
Rare Disease Specialist
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 Autosomal dominant adult-onset proximal spinal muscular atrophy.
Community
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Start the conversation →Latest news about Autosomal dominant adult-onset proximal spinal muscular atrophy
Disease timeline:
New recruiting trial: Long Term Trajectories of SMA Patients Receiving or Not Disease-modifying Treatments
A new clinical trial is recruiting patients for Autosomal dominant adult-onset proximal spinal muscular atrophy
New recruiting trial: Active NBS Study: Decentralised Monitoring Motor Development in Children With Duchenne Muscular Dystrophy or Spinal Muscular Atrophy Identified by Newborn Screening
A new clinical trial is recruiting patients for Autosomal dominant adult-onset proximal spinal muscular atrophy
New recruiting trial: High-intensity Interval Training in Patients With Spinal Muscular Atrophy
A new clinical trial is recruiting patients for Autosomal dominant adult-onset proximal spinal muscular atrophy
New recruiting trial: A Review of the Management and Outcomes of Children With SMA in the West Midlands During 2017-2022
A new clinical trial is recruiting patients for Autosomal dominant adult-onset proximal spinal muscular atrophy
New recruiting trial: Real World Clinical Effectiveness & Safety of Vesemnogene Lantuparvovec for Spinal Muscular Atrophy (SMA) in Low-middle Income Countries (LMIC).
A new clinical trial is recruiting patients for Autosomal dominant adult-onset proximal spinal muscular atrophy
New recruiting trial: Test of Aquatic Mobility of SMA Infants
A new clinical trial is recruiting patients for Autosomal dominant adult-onset proximal spinal muscular atrophy
New recruiting trial: Evaluation of Safety and Efficacy of Gene Therapy Drug in the Treatment of Spinal Muscular Atrophy (SMA) Type 1 Patients
A new clinical trial is recruiting patients for Autosomal dominant adult-onset proximal spinal muscular atrophy
New recruiting trial: prTMS as an Intervention for Bradykinesia in Parkinson's Disease
A new clinical trial is recruiting patients for Autosomal dominant adult-onset proximal spinal muscular atrophy
New recruiting trial: A Registry Based Randomized-Controlled Trial of an Upper Limb Exergaming Intervention for Children and Adolescents With Spinal Muscular Atrophy
A new clinical trial is recruiting patients for Autosomal dominant adult-onset proximal spinal muscular atrophy
New recruiting trial: rTMS as an Intervention for Levodopa-induced Dyskinesia
A new clinical trial is recruiting patients for Autosomal dominant adult-onset proximal spinal muscular atrophy
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.
Common questions about Autosomal dominant adult-onset proximal spinal muscular atrophy
What is Autosomal dominant adult-onset proximal spinal muscular atrophy?
Autosomal dominant adult-onset proximal spinal muscular atrophy (also known as adult-onset proximal SMA or late-onset SMA type 4) is a rare neuromuscular disorder characterized by progressive degeneration of the lower motor neurons in the spinal cord. Unlike the more common childhood-onset forms of spinal muscular atrophy, this condition manifests in adulthood, typically after the age of 30, and follows an autosomal dominant inheritance pattern rather than the autosomal recessive pattern seen in classical SMA caused by SMN1 mutations. The disease primarily affects the motor neurons that contr
How is Autosomal dominant adult-onset proximal spinal muscular atrophy inherited?
Autosomal dominant adult-onset proximal spinal muscular atrophy follows a autosomal dominant inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Autosomal dominant adult-onset proximal spinal muscular atrophy typically begin?
Typical onset of Autosomal dominant adult-onset proximal spinal muscular atrophy is adult. Age of onset can vary across affected individuals.
Are there clinical trials for Autosomal dominant adult-onset proximal spinal muscular atrophy?
Yes — 14 recruiting clinical trials are currently listed for Autosomal dominant adult-onset proximal spinal muscular atrophy on UniteRare. See the clinical trials section on this page for phase, sponsor, and site details sourced from ClinicalTrials.gov.
Which specialists treat Autosomal dominant adult-onset proximal spinal muscular atrophy?
25 specialists and care centers treating Autosomal dominant adult-onset proximal spinal muscular atrophy are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.