In females, SHG is confirmed by measurement of oestradiol (E2), FSH, and LH, assessment in the presence of oligomenorrhoea or amenorrhoea after excluding pregnancy and other causes of menstrual abnormality (such as hyperandrogenaemia, hyperprolactinaemia, thyroid disorders), particularly when no other pituitary hormone deficiency has been documented. Here, PLOD1 is linked to hypopituitarism.