PLOD1 and Infertility: As the major causes of infertility are sperm abnormalities, ovulation dysfunction, and fallopian tube obstruction, the preliminary adviced investigations for the infertile couple should be focused on semen analysis (to be compared with the WHO reference values [27]), detection of ovarian function by hormonal assay (early follicular FSH and LH levels, and mid-luteal progesterone), and evaluation of tubal patency by hysterosalpingography (HSG) [17-32], (Appendix 3).