CYBB and spermatogenic failure, X-linked, 3: The third patient had a large deletion spanning approximately 1.8 Mbp, leading to the complete loss of many genes, including CYBB and XK, and a partial loss of CFAP47 and SYTL5. Variants in XK have been associated with McLeod syndrome (OMIM 300842), while variants in CFAP47 may be associated with Spermatogenic failure, X-linked 3 (OMIM 301059).