Markesbery-Griggs myopathy, Miyoshi type (MM) is a rare type of myopathy, a form muscular dystrophy with the main involvement of the lower girdle and distal parts of the legs. Due to complexity of genetic testing, the diagnosis is mainly made on the neurological examination of the patient, which adds value to this case report. The childhood or adolescence onset of the disease is characterized initially by the calf muscles` wasting, accompanied by the severe elevation of the serum creatine kinase, as well as a slowly progressive ascending course. The disease refers to dysferlinopathies with various mutations in the DYSF gene. The dysferlin protein is localized in the plasma membrane and in the T-tubule system of skeletal muscles. Physiologically, skeletal muscles are constantly exposed to micromembrane lesions. Depending on the severity, these damages are restored using various complexes. One of the main reparative complexes is the dysferlin-dependent mechanism. Mutations can lead to a defect in the membrane repair, causing the influx of Ca 2+ into the cell, which leads to a cell`s destruction. There are three genetically identifiable types of Miyoshi myopathy: MMD1, MMD2, MMD3. The main clinical signs of the disease are the muscle weakness and atrophy, with predominant involvement of the distal parts of the lower limbs, especially in the gastrocnemius and plantar muscles. The MM causes tip toe walking disturbances and difficulties in climbing the stairs. Progression of the disease and further atrophy leads to the wasting of the lower girdle muscles, mainly gluteal ones. Peculiarity of these myopathies is the absence of cardiomyopathy, due to the immunity of cardiomyocytes to a deficiency of the protein dysferelin. Diagnosis is made on the basis of muscle biopsy and molecular genetic testing. The gold standard is immunoblotting or immunohistochemistry. One of treatment methods is the use of improperly folded dysferlin (treatment with a proteasome inhibitor MG-132) in fibroblasts with restoration of membrane sealing. The aim of this case report is to present an example of a possible clinical diagnosis of MM in a young man, in the absence of opportunities for molecular genetic testing.
2+0 CYP21A2 deletion carrier — a limitation of the genetic testing and counseling: A case report
