In EDMD, several SUN1 or SUN2 mutations increase disease severity in patients carrying other EDMD-related gene mutations, such as LMNA (encoding lamin A/C), EMD (encoding emerin), and MYBPC3 (encoding myosin-binding protein C3), suggesting that SUN1 and SUN2 function as disease modifier genes [103]. This evidence concerns the gene MYBPC3 and Emery-Dreifuss muscular dystrophy.