Overview
Kennedy disease, also known as spinal and bulbar muscular atrophy (SBMA) or X-linked bulbospinal neuronopathy, is a rare, slowly progressive neurodegenerative disorder caused by a trinucleotide (CAG) repeat expansion in the androgen receptor (AR) gene on the X chromosome. The disease primarily affects males and is characterized by degeneration of lower motor neurons in the brainstem and spinal cord, leading to progressive muscle weakness and atrophy. Because the androgen receptor is involved, the condition also has significant endocrine manifestations. Key clinical features include proximal limb muscle weakness and wasting, bulbar symptoms such as difficulty swallowing (dysphagia), slurred speech (dysarthria), and tongue fasciculations. Patients frequently experience muscle cramps, tremor, and widespread fasciculations. Sensory neuropathy may also be present. Endocrine-related signs include gynecomastia (breast enlargement), testicular atrophy, reduced fertility, and erectile dysfunction. Elevated creatine kinase (CK) levels are commonly found on laboratory testing. Symptoms typically begin between the ages of 30 and 50, though onset can vary. Kennedy disease progresses slowly, and most patients remain ambulatory for many years after symptom onset, though some may eventually require wheelchair assistance. Life expectancy is generally near normal, though aspiration pneumonia due to bulbar dysfunction can be a serious complication. There is currently no cure or disease-modifying treatment for Kennedy disease. Management is supportive and multidisciplinary, including physical therapy, speech therapy, nutritional support for swallowing difficulties, and endocrine management. Clinical trials have investigated androgen-reducing therapies such as leuprorelin and dutasteride, but results have been inconclusive. Genetic counseling is important for affected families, as carrier females are generally asymptomatic or may have mild symptoms such as muscle cramps.
Also known as:
Clinical phenotype terms— hover any for plain English:
X-linked recessive
Carried on the X chromosome; typically affects males more than females
Adult
Begins in adulthood (age 18 or older)
FDA & Trial Timeline
10 eventsUniversity Health Network, Toronto — PHASE2
Cedars-Sinai Medical Center — PHASE2
TechnoGenesys, Inc. — PHASE1
Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins — PHASE2
Medical College of Wisconsin — PHASE2
Jiangsu HengRui Medicine Co., Ltd. — PHASE3
Novartis Pharmaceuticals — PHASE1, PHASE2
Bayer
Ankara Etlik City Hospital
Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.
Treatments
No FDA-approved treatments are currently listed for Kennedy disease.
6 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 centersNational Institutes of Health Clinical Center
📍 Bethesda, Maryland
👤 Payal P Khincha, M.D.
👤 Christopher Grunseich, M.D.
Stanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🔬 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
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🏥 NORDBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
Travel Grants
No travel grants are currently matched to Kennedy disease.
Community
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Start the conversation →Latest news about Kennedy disease
Disease timeline:
New recruiting trial: ADT +/- Darolutamide in de Novo Metastatic Prostate Cancer Patients With Vulnerable Functional Ability (PEACE6-Vulnerable)
A new clinical trial is recruiting patients for Kennedy disease
New recruiting trial: A Study of Enzalutamide, Enzalutamide in Combination With Mifepristone, or Chemotherapy in People With Metastatic Breast Cancer
A new clinical trial is recruiting patients for Kennedy disease
New recruiting trial: Apa/Enza-short Study: Shorter Treatment With Androgen Receptor Pathway Inhibitor in Patients With Low-volume Metastatic Castration-sensitive Prostate Cancer
A new clinical trial is recruiting patients for Kennedy disease
New recruiting trial: Clinical Trial of Mexiletine Hydrochloride for Spinal and Bulbar Muscular Atrophy
A new clinical trial is recruiting patients for Kennedy disease
New recruiting trial: A Study of JSB462 (Luxdegalutamide) Plus Lutetium (177Lu) Vipivotide Tetraxetan in Patients With Metastatic Castration Resistant Prostate Cancer (mCRPC)
A new clinical trial is recruiting patients for Kennedy disease
New recruiting trial: Specified Drug-Use Survey of Leuprorelin Acetate Injection Kit 11.25 mg "All-Case Investigation: Spinal and Bulbar Muscular Atrophy (SBMA)"
A new clinical trial is recruiting patients for Kennedy disease
New recruiting trial: Study Evaluating the Safety, Tolerability, and Efficacy of Xaluritamig in Combination With Androgen Receptor Pathway Inhibitors in Participants With Metastatic Hormone-sensitive Prostate Cancer
A new clinical trial is recruiting patients for Kennedy disease
New recruiting trial: Evaluation of Clinical Outcomes of Chemotherapy or Androgen-receptor Targeting Agent (Alone or Combined) or Radiotherapy on Primary Tumor in Addition to Androgen Deprivation Therapy in HOrmone-Sensitive Metastatic Prostate Cancer Patients
A new clinical trial is recruiting patients for Kennedy disease
New recruiting trial: A Study of Talazoparib With or Without Enzalutamide in People With Prostate Cancer Who Have Previously Received Abiraterone Acetate
A new clinical trial is recruiting patients for Kennedy disease
New recruiting trial: Docetaxel to Androgen Receptor Pathway Inhibitors in Patients With Metastatic Castration Sensitive Prostate Cancer and Suboptimal PSA Response
A new clinical trial is recruiting patients for Kennedy disease
Caregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
Rare disease caregiving can be isolating. Connect with counseling and peer support.
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 Kennedy disease
What is Kennedy disease?
Kennedy disease, also known as spinal and bulbar muscular atrophy (SBMA) or X-linked bulbospinal neuronopathy, is a rare, slowly progressive neurodegenerative disorder caused by a trinucleotide (CAG) repeat expansion in the androgen receptor (AR) gene on the X chromosome. The disease primarily affects males and is characterized by degeneration of lower motor neurons in the brainstem and spinal cord, leading to progressive muscle weakness and atrophy. Because the androgen receptor is involved, the condition also has significant endocrine manifestations. Key clinical features include proximal l
How is Kennedy disease inherited?
Kennedy disease follows a x-linked recessive inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Kennedy disease typically begin?
Typical onset of Kennedy disease is adult. Age of onset can vary across affected individuals.
Are there clinical trials for Kennedy disease?
Yes — 6 recruiting clinical trials are currently listed for Kennedy disease on UniteRare. See the clinical trials section on this page for phase, sponsor, and site details sourced from ClinicalTrials.gov.
Which specialists treat Kennedy disease?
25 specialists and care centers treating Kennedy disease are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.