Overview
Distal hereditary motor neuropathy (dHMN), also called distal spinal muscular atrophy (dSMA) or Charcot-Marie-Tooth disease type 2 (in some classifications), is a rare inherited nerve disease that mainly affects the motor nerves — the nerves that send signals from the brain and spinal cord to the muscles. Unlike some other nerve diseases, dHMN usually spares the sensory nerves, meaning most people do not lose the ability to feel touch, pain, or temperature. The disease causes the motor nerve cells to slowly stop working properly, which leads to muscle weakness and wasting, especially in the hands, feet, and lower legs. The most common early signs are weakness and shrinking of the muscles in the feet and lower legs, which can cause foot drop (difficulty lifting the front of the foot), an unusual walking pattern, and frequent tripping or falls. Over time, weakness can spread to the hands and forearms. Some people also develop high-arched feet (pes cavus) or curled toes (hammer toes). The severity varies a great deal from person to person, even within the same family. dHMN is actually a group of related conditions caused by changes (mutations) in many different genes. There is currently no cure, but physical therapy, orthotics, and supportive care can help people maintain mobility and quality of life for many years. Most people with dHMN have a normal or near-normal lifespan.
Also known as:
Key symptoms:
Weakness in the feet and lower legsMuscle wasting (shrinking) in the feet, lower legs, and sometimes handsFoot drop — difficulty lifting the front part of the foot when walkingHigh-arched feet (pes cavus)Curled or clawed toes (hammer toes)Frequent tripping or fallsDifficulty walking or runningWeakness in the hands and fingers in some typesBreathing difficulties in some severe or specific subtypesVoice changes or swallowing problems in certain subtypesReduced or absent reflexes in the ankles and kneesMuscle cramps or stiffness
Variable
Can be inherited in different ways depending on the underlying gene
Variable
Can begin at different ages, from infancy through adulthood
Treatments
4 availableITVISMA
treatment of spinal muscular atrophy (SMA) in adult and pediatric patients 2 years of age and older with confirmed mutation in survival motor neuron 1 (SMN1) gene
EVRYSDI
treatment of spinal muscular atrophy (SMA) in patients 2 months of age and older
Zolgensma
Indicated for the treatment of pediatric patients less than 2 years of age with spinal muscular atrophy (SMA) with bi-allelic mutations in the survival motor neuron 1 (SMN1) gene.
Spinraza
Treatment of spinal muscular atrophy in pediatric and adult patients
Clinical Trials
View all trials with filters →No actively recruiting trials found for Distal hereditary motor neuropathy at this time.
New trials open frequently. Follow this disease to get notified.
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
Financial Resources
4 resourcesTravel Grants
No travel grants are currently matched to Distal hereditary motor neuropathy.
Community
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Start the conversation →Latest news about Distal hereditary motor neuropathy
1 articlesCaregiver 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.
Questions for your doctor
Bring these to your next appointment
- Q1.Which specific gene is causing my dHMN, and what does that mean for how my disease will progress?,Should other family members be tested, and what are the chances of passing this on to my children?,What type of physical therapy program is best for my situation, and how often should I go?,Do I need regular breathing tests, and are there any signs I should watch for that would mean I need breathing support?,Are there any clinical trials or research studies I might be eligible to join?,What assistive devices or orthotics would help me most right now, and when should I consider them?,How often should I have follow-up appointments, and what tests will be done to track my condition over time?
Common questions about Distal hereditary motor neuropathy
What is Distal hereditary motor neuropathy?
Distal hereditary motor neuropathy (dHMN), also called distal spinal muscular atrophy (dSMA) or Charcot-Marie-Tooth disease type 2 (in some classifications), is a rare inherited nerve disease that mainly affects the motor nerves — the nerves that send signals from the brain and spinal cord to the muscles. Unlike some other nerve diseases, dHMN usually spares the sensory nerves, meaning most people do not lose the ability to feel touch, pain, or temperature. The disease causes the motor nerve cells to slowly stop working properly, which leads to muscle weakness and wasting, especially in the ha
Which specialists treat Distal hereditary motor neuropathy?
17 specialists and care centers treating Distal hereditary motor neuropathy are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.
What treatment and support options exist for Distal hereditary motor neuropathy?
4 patient support programs are currently tracked on UniteRare for Distal hereditary motor neuropathy. See the treatments and support programs sections for copay assistance, eligibility, and contact details.