For example, sequences of the genes SRY (sex-determining region of the Y chromosome, located on Yp short arm) (Figure 1), TSPY (pericentomeric region), and DAZ (deleted in azoospermia, located on Yq long arm).16,17 In cases with a 45,X karyotype, without mosaicism detected by cytogenetics analysis of 100 metaphases, we also collect buccal cells and urine, and perform nested PCR with the primers for TSPY sequences. The gene discussed is TSPY1; the disease is Azoospermia.