The Study Of Two Cases Of Secondary Dystrophin Protein Deficiency Phenomenon And Literature Review

Background and ObjectiveDystrophin protein is distributed at the plasma membrane of all muscles a nd part of neurons. As a part of the membrane cytoskeleton, dystrophin with o ther protein such as dystroglycans and sarcoglycans compose DAPC, dystrophin associated protein complex, which play a structural role in ensuring membrane stability and force transduction during muscle contraction. The protein is enco ded by the X-linked dystrophin gene whose mutations lead to dystrophin protei n translation disorder, and result in Duchenne or Becker muscle dystrophy in c linic. These are primary dystrophin deficiency. In this article we report two cas es of secondary dystrophin deficiency, summarize and differentiate the common dystrophin deficiency phenomenon.Materials and MethodsThe two patients are outpatients of neurology department, shandong qilu h ospital, take the muscle biopsy because of limbs’shake, epilepsy and myasthen ia. As a control we selected2DMD,1BMD and1routine histochemistry sta ins normal muscle cases from the nerve and muscular disease institute of shan dong qilu hospital. For above muscle cases we carry out the routine histochem istry stains, immunohistochemistry stains, dystrophin protein immunofluoresence stain, dystrophin protein western blot and dystrophin gene tests.ResultsPatient1routine histochemistry stains show a mild neurogenic damage, im munohistochemistry stains and immunofluoresence stain show that dystrophin-R od stain was weaken than the control, dystrophin protein western blot shows th e decrease of the protein expression, the dystrophin gene MLPA test shows79exons of the gene are normal, and the NGS test show several polymorphic sit e:rs1484852, rs1800280, rs1379871,rs187617705, rs228406.Patient2routine histochemistry stains show roughly normal muscle tissue, immunohistochemistry stains and immunofluoresence stain show that dystrophin Rod stain was not dyed widespreadly in the muscle fibers, dystrophin protei n western blot shows the decrease of the protein expression, the dystrophin ge ne MLPA test shows79exons of the gene are normal, and the NGS test sho w a hemizygote mutation:C.4048C>T, p.(Arg1350Cys).ConclusionsThere is no pathogenic mutations of these two patients’dystrophin genes, we conclude the dystrophin protein deficiency is secondary. As there are novel muscle contraction in the disease course of both patients, which lead to the s econdary dystrophin deficiency. In the diagnosis of neuromuscular disease, we s hould on the basis of routine histochemistry stains and immunohistochemistry s tains, combine with clinical feature, and immunofluoresence stain, protein west ern blot and gene tests in necessity.