NK cells are key innate immune players with direct cytotoxic activity and antibody dependent cellular cytotoxicity (ADCC), triggered upon the recognition of ligands on MM cells by activating receptors such as NKG2D, CD16, 2B4, NKp80 or DNAM-1 [91,92], regulated by major histocompatibility complex class I (MHC-I)-binding inhibitory receptors, such as killer cell Ig-like receptors (KIR) or CD94/NKG2A [93]. The gene discussed is KLRK1; the disease is Miyoshi myopathy.