X-linked myopathy (XL-MTM)

The X-linked myotubular myopathy is a hereditary disorder that affects the skeletal muscles in the body. In contrast to the centronuclear myopathy (CNM), which also occurs in the Labrador Retriever, the genetic defect is associated with the X﷓chromosome. The MTM1 gene is responsible for the production of mytubularin, which is an important factor for development and especially maintenance of muscular function. If myotubularin production is hindered because of a defective MTM1 gene, the regeneration of the excitation-contraction coupling mechanism is malfunctioning. Clinical signs for this disease can be seen from birth. Symptoms are strong hypotonia, muscle atrophy and progressive weakening of the hind limbs. This is usually accompanied by breathing difficulties, which can lead to death by suffocation.