Mutations in the LMNA and in some of the genes listed above, i.e. EMD, SYNE1, SYNE2 and TMEM43, as well as FHL-1 gene, encoding a four and a half LIM domains protein 1 (FHL1), which does not belong to nuclear envelope proteins, but is expressed in striated muscles and probably takes part in sarcomere assembly, are associated with pathogenesis of skeletal muscle diseases, characterized by various clinical course and intra- and inter-familial variability, including Emery-Dreifuss muscular dystrophy (EDMD), which are to be discussed below [10–14]. The gene discussed is SUN2; the disease is Emery-Dreifuss muscular dystrophy.