Bethlem Myopathy: Symptom, Diagnosis, Treatment

Overview

Bethlem myopathy (BM), is a rare and hereditary muscle disorder with an estimated incidence of 0.77 per 100,000 individuals, usually causing muscle weakness and joint stiffness, or referred to as contractures.


Causes

BM is often caused by the mutations in the type VI collagen called COL6A1, COL6A2, or COL6A3 genes. This kind of collagen type IV protein plays an important role in the muscles, particularly skeletal muscles.

The exact reason why these kind mutations occur in the body is not well-understood. What we know is that mutations in the type VI collagen genes could lead to the formation of abnormal types VI collagen and reduced amounts of type VI collagen, which disrupts the extracellular matrix surrounding muscle cells, eventually leading to the progressive muscle weakness and other signs and symptoms of BM.


Symptoms

Each patient may experience symptoms differently depending on the severity of the disease and specific condition of the patients.

For Babies

  • Hypotonia;
  • Muscle weakness;
  • Talipes (Clubfoot);
  • stiffness in neck with limited mobility.
  • Contractures.

For Adults

  • Tight tendons;
  • Poor stamina;
  • Limited mobility;
  • General muscle weakness;
  • Unusual look of the skin: surfaces of the arms and legs look and feel rough and dry like a snake.


Diagnosis

BM is typically diagnosed based on a clinical evaluation testing, including:

  • A muscle biopsy: the way of reaching a precise diagnosis;
  • Muscle ultrasound;
  • Blood test measuring creatine kinase (CK) levels: these levels will typically be normal or only slightly elevated;
  • Skin biopsy;
  • Muscle MRI;
  • Electromyography (EMG);
  • Genetic testing of the COL6A1, COL6A2, and COL6A3 genes can confirm the diagnosis.


Treatment

There is no cure of Bethlem myopathy. There are only ways to alleviate and manage the symptoms and prevent any further complications.

  • Medications is the first option for treatment of BM based on its severity.
  • Physical therapy will be suggested to stretch tight joints and maintain the flexibility and suppleness of your muscles.
  • Surgery will be taken to release the Achilles tendon.
  • Remain active and manage weights. These are also considered as an important part of treatment of BM.
  • Proper nutrition and adequate sleep can help muscle repair and relieve some symptoms of BM.


Prognosis

It is believed that BM will not shorten a person’s lifespan. But the symptoms will affect them for the whole lives. With the progression of disease, more than 50% of patients will require a walker, cane, or wheelchair.


Keywords: Bethlem myopathy; BM.


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* The Content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.