PLOD1 and Klinefelter syndrome: Comparing the testis size and hormonal levels in samples obtained from severe oligozoospermic group, cryptozoospermic group (from men with non-mosaic Klinefelter’s syndrome), and control group, the results showed that, the volumes of both the right and the left testis, and the levels of T and T/LH were significantly lower than those in the control group (p=0.000).