Summary about Disease
Yamagata progressive hereditary sensory neuropathy (HSN1) is a rare, inherited neurological disorder characterized by progressive sensory loss, primarily affecting the lower limbs. This leads to difficulties with pain and temperature perception, potentially resulting in injuries that go unnoticed. It is one of several types of hereditary sensory neuropathies, each with its own genetic cause and symptom profile. The Yamagata type is typically associated with specific genetic mutations.
Symptoms
Progressive sensory loss, primarily in the feet and legs.
Decreased or absent pain and temperature sensation.
Ulcers and infections in the feet (due to unnoticed injuries).
Burning or shooting pains in affected areas.
Joint damage (Charcot joints) in the feet and ankles.
Muscle weakness and atrophy in the lower limbs can develop over time.
Possible hearing loss in some individuals.
Causes
Yamagata HSN1 is caused by genetic mutations. Specifically, it is most commonly associated with mutations in the SPTLC1 gene. This gene provides instructions for making a subunit of serine palmitoyltransferase (SPT), an enzyme involved in the first step of sphingolipid biosynthesis. The mutations disrupt the normal function of the SPT enzyme, leading to the accumulation of atypical deoxysphingolipids, which are thought to be toxic to sensory neurons. It is inherited in an autosomal dominant pattern, meaning only one copy of the mutated gene is needed to cause the disorder.
Medicine Used
There is no cure for Yamagata HSN1, and treatment focuses on managing symptoms and preventing complications. Medications may include:
Pain relievers: To manage neuropathic pain (e.g., gabapentin, pregabalin, amitriptyline).
Antibiotics: To treat infections of ulcers or wounds.
Bisphosphonates: have been investigated to help with bone loss.
Is Communicable
No, Yamagata progressive hereditary sensory neuropathy is not communicable. It is a genetic disorder and cannot be spread from person to person.
Precautions
Foot care: Regular inspection of feet for injuries, blisters, or ulcers. Proper footwear to prevent injuries. Consult with a podiatrist regularly.
Skin care: Maintain skin integrity to prevent infections.
Avoid extreme temperatures: Be cautious of hot water, heating pads, and cold temperatures to prevent burns or frostbite due to impaired sensation.
Fall prevention: Address muscle weakness and balance issues with physical therapy, assistive devices (e.g., canes, walkers), and home modifications.
Genetic counseling: For individuals with a family history of HSN1, genetic counseling can help assess the risk of inheriting or passing on the gene.
How long does an outbreak last?
Yamagata HSN1 is not characterized by outbreaks. It is a chronic, progressive condition. Symptoms develop gradually over time. Ulcers or infections, which are complications of the disease, may occur and require acute treatment, but the underlying neuropathy is ongoing.
How is it diagnosed?
Diagnosis typically involves:
Clinical evaluation: Assessment of symptoms, neurological examination, and family history.
Nerve conduction studies: To assess nerve function. These studies typically show reduced or absent sensory nerve action potentials.
Genetic testing: To confirm the diagnosis by identifying a mutation in the SPTLC1 gene.
Skin biopsy: A skin biopsy may demonstrate loss of epidermal nerve fibers.
Timeline of Symptoms
The onset and progression of symptoms can vary, but a general timeline may include:
Childhood/Adolescence: Often, the first symptoms appear during childhood or adolescence, starting with decreased pain and temperature sensation in the feet.
Early Adulthood: Ulcers and infections of the feet may become more frequent.
Adulthood: Sensory loss progresses, potentially leading to Charcot joints, muscle weakness, and difficulty with walking.
Later Life: Complications can increase, impacting mobility and quality of life. Hearing loss may develop in some cases.
Important Considerations
Early diagnosis and proactive management are crucial to prevent complications and maintain quality of life.
A multidisciplinary approach involving neurologists, podiatrists, physical therapists, and genetic counselors is recommended.
Patients need to be educated about the importance of foot care and precautions to avoid injuries.
Genetic testing is important for accurate diagnosis and family planning.
Research is ongoing to identify potential therapies for HSN1.