– Calreticulin-3 belongs to the calreticulin family, members of which are calcium binding chaperones localized mainly in the endoplasmic reticulum. It can be divided into a N-terminal globular domain, a proline-rich P-domain forming an elongated arm-like structure and a C-terminal acidic domain. During spermatogenesis process, Calreticulin-3 may act as a lectin-independent chaperone for specific client proteins such as ADAM3. Defects in CALR3 are the cause of familial hypertrophic cardiomyopathy type 19 (CMH19), it is a hereditary heart disorder characterized by ventricular hypertrophy, which is usually asymmetric and often involves the interventricular septum. The symptoms include dyspnea, syncope, collapse, palpitations, and chest pain.