Summary about Disease
Dejerine-Sottas disease (DSD), also known as Charcot-Marie-Tooth disease type 3 (CMT3), is a rare, severe, inherited neurological disorder that affects the peripheral nerves. It is characterized by delayed motor development in infancy, progressive muscle weakness, sensory loss, and skeletal deformities. DSD is a demyelinating neuropathy, meaning that the myelin sheath (the protective covering around nerve fibers) is damaged, leading to impaired nerve signal transmission.
Symptoms
Symptoms typically begin in infancy or early childhood and can include:
Delayed motor milestones (e.g., delayed walking)
Progressive muscle weakness and atrophy, particularly in the legs and feet
Sensory loss (numbness, tingling) in the hands and feet
Skeletal deformities, such as pes cavus (high-arched feet), hammer toes, and scoliosis
Enlarged nerves (palpable thickening of peripheral nerves)
Hypotonia (low muscle tone) in infancy
Tremors
Hearing loss (in some cases)
Pupillary abnormalities
Causes
DSD is caused by genetic mutations that affect the structure or function of proteins essential for the formation and maintenance of the myelin sheath. These mutations are typically inherited in an autosomal recessive or autosomal dominant manner, although de novo (new) mutations can also occur. Genes commonly associated with DSD include:
PMP22 (Peripheral Myelin Protein 22)
MPZ (Myelin Protein Zero)
EGR2 (Early Growth Response 2)
PRX (Periaxin)
MTMR2 (Myotubularin Related Protein 2)
Medicine Used
4. Medicine used There is no cure for DSD, and treatment focuses on managing symptoms and improving quality of life. Treatments may include:
Physical therapy: To maintain muscle strength and flexibility, and to prevent contractures.
Occupational therapy: To help with activities of daily living.
Orthotics: Braces and supports to help stabilize the ankles and feet, and to improve gait.
Pain management: Medications to relieve pain associated with nerve damage.
Surgery: To correct skeletal deformities, such as foot deformities or scoliosis.
Assistive devices: Wheelchairs, walkers, and other devices to aid mobility.
Medications: Certain medications might be prescribed to manage specific symptoms like nerve pain or tremors. Examples may include pain relievers, anti-seizure medications (for nerve pain), or tremor-reducing drugs.
Is Communicable
DSD is not communicable. It is a genetic disorder and cannot be spread from person to person.
Precautions
Since DSD is a genetic condition, there are no specific precautions to prevent its occurrence in affected individuals. However, for families with a history of DSD or other inherited neuropathies, genetic counseling and testing may be beneficial before family planning. Precautions for those living with the disease revolve around managing the symptoms.
Regular physical therapy to maintain muscle strength and flexibility.
Use of assistive devices to prevent falls and injuries.
Proper foot care to prevent skin breakdown and infections due to sensory loss.
Regular medical checkups to monitor disease progression and manage symptoms.
Avoid activities that may cause injury, especially to the hands and feet, due to decreased sensation.
How long does an outbreak last?
DSD is not an "outbreak" type of disease. It is a chronic, progressive condition. The symptoms typically develop in infancy or early childhood and gradually worsen over time. There is no defined "outbreak" period; rather, it's a lifelong condition with fluctuating severity of symptoms.
How is it diagnosed?
Diagnosis of DSD typically involves:
Clinical examination: Assessment of the patient's symptoms, neurological function, and family history.
Nerve conduction studies (NCS): To measure the speed of nerve signal transmission. In DSD, NCS typically show significantly reduced nerve conduction velocities.
Electromyography (EMG): To assess the electrical activity of muscles.
Nerve biopsy: Examination of a small sample of nerve tissue under a microscope. This can help to identify demyelination and other characteristic features of DSD.
Genetic testing: To identify specific gene mutations associated with DSD. This is the most definitive diagnostic test.
MRI: To look at the spinal cord and brain to rule out other causes.
Timeline of Symptoms
The timeline of symptoms in DSD is variable but typically follows this pattern:
Infancy: Delayed motor milestones (e.g., delayed sitting, crawling, walking), hypotonia (low muscle tone).
Early childhood: Progressive muscle weakness and atrophy, sensory loss in the hands and feet, skeletal deformities (pes cavus, hammer toes).
Childhood/Adolescence: Worsening muscle weakness and atrophy, increasing sensory loss, development of scoliosis, enlarged nerves.
Adulthood: Continued progression of symptoms, potential for significant disability.
Important Considerations
Genetic counseling: Important for families with a history of DSD to understand the inheritance pattern and recurrence risk.
Early diagnosis and intervention: Can help to maximize function and quality of life.
Multidisciplinary care: Involving neurologists, physical therapists, occupational therapists, orthopedists, and other specialists.
Emotional support: For patients and families dealing with the challenges of a chronic, progressive condition.
Research: Ongoing research is aimed at developing new treatments for DSD and other inherited neuropathies.
Disease variability: The severity and progression of DSD can vary significantly between individuals, even within the same family.