SGCZ is one of six members of the sarcoglycan gene-family that combine to form two different quarto-meric sarcoglycan complexes; one found in striated muscles that include SGCA, SGCB, SGCD and SGCG, and the other which is found in smooth muscles and include SGCB, SGCD, SGCE and SGCZ. Smooth muscle structures have recently been identified in endometroid lesions [26] establishing a plausible functional link to the involvement of SGCZ in endometriosis. This evidence concerns the gene SGCZ and endometriosis.