The research team led by Marc Bitoun and Norma Romero and directed by Pascale Guicheney (Inserm U582 “ Physiopathology and therapy of striated muscle”) identified on chromosome 19, the gene responsible for a congenital myopathy: the dominant autosomic form of centronuclear myopathy. The gene involved is dynamin 2 (DNM2). The expressed mutant proteins appear to interfere with one or more functions of the centrosome. This discovery is the first step towards understanding the mechanisms at the origin of the central, non-peripheral position of muscle fibre nuclei. Before leading to a therapeutic track, this discovery will make it possible in the future, to establish a precise diagnosis and to consider prenatal diagnosis for couples at risk. It represents the beginning of a series of studies performed particularly within team 4 “Cytoskeleton architecture and cell polarization” of UMR 787/Myology Group, directed by Edgar Gomes.

Pascale Guicheney’s group, in collaboration with Australian researchers, have shown that the selenoprotein 1 (SEPN1) gene is associated with a congenital myopathy with fibre disproportion (congenital fibre-type disproportion-CFTD). This protein is already known to be linked to rigid spine syndrome, multicore myopathy and Mallory body myopathy. A new family of myopathies was thus baptized: selenopathies. Insulin resistance could be one of the characteristics specific to certain selenopathies.

Pascale Laforêt (Myology Institute) contributed to the discovery that mutations in the gene coding for adipose triglyceride lipase (ATGL) were responsible for a myopathy with lipid overload. They involve the formation of a non-functional truncated protein. ATGL no longer fulfil its enzymatic function in the first stage of triglyceride degradation. Result: lipids accumulate in the cells in the form of vacuoles. The new disease thus characterized NLSDM (neutral lipid storage disease with myopathy), has a recessive autosomic transmission. It is very rare, probably accounting for 4-5 cases in 1000. The discovery of this gene now makes it possible to specify the diagnosis and opens the door to treatment (possibility to act on triglyceride catabolism).