MFM are clinically, morphologically, and genetically heterogeneous neuromuscular diseases frequently affecting cardiac and respiratory systems. A distinctive

morphological marker is the focal disorganization of myofibrils associated with deposits of different proteins in skeletal muscle.There are few reports suggesting that gene expression are deregulated.

We selected patients with confirmed previous myofibrillar myopathy diagnosis in order to test mRNA expression genes responsible for this disorder. The genes studied were desmin(DES), myotiline(MYOT), filamin C(FLNC) and ZASP)   them which were compared with controls. We used RT-qPCR in a thermal cycler. The specific primers for these genes amplification were created using the Primer3 Input 0.4.0 software, available in http://frodo.wi.mit.edu/primer3/. We also analysed control samples

A total of 17 patients were studied with the following mutations: 7(41.2%) DES; 2(11.8%) MYOT; 3(17.6%)FLNC; 5(29.4%) ZASP. 8 females and 9 males.Mean age of diagnosis was 44 years. We compared them with controls: 16: 10 females and 7 males. Mean age: 47 years.

Gene expression was increased in patients with following mutations: desmin(p<0.0001), filamin C(p<0.0001), zasp(p<0.0001). Myotilin did not demonstrate significant statistical difference in relation to controls(p<0.9869).

Our results corroborate the immunohistochemical findings showing expression in muscle biopsies. The clinical heterogeneity may be related to the concentration of expression in each patient suggesting that the pathogenesis may be related to toxic gain of function.