DAZ1 and Infertility: Seventeen out of 119 (14.3%) azoospermic patients and two out of 89 (2.2%) patients with OAT had Y chromosome microdeletions. The AZFc locus, mainly DAZ gene cluster was the most frequently deleted region. Other chromosomal and genetic abnormalities were also observed in the NOA and OAT patients.This means that diverse chromosomal abnormalities and deletions of Y chromosome can cause spermatogenic breakdown resulting in chromosomally derived infertility.