AFAB Hypogonadism or Müllerian Hypogonadism is an intersex variation - more specifically, a form of hypogonadism - leading to a reduction in the output of Müllerian sex hormones including estrogen and progesterone in AFAB or otherwise CTF individuals, due to decreased functionality of the ovaries. Hypogonadism can be primary, meaning it's caused by a problem with the ovaries, or it can be secondary hypogonadism, meaning it's caused by a problem with the signals sent from the brain to the ovaries.
One symptom includes the effects of low estrogen, which will cause one to not begin menstruation and will having slow or absent breast growth. Those with acquired hypogonadism will stop menstruating and will experience symptoms of menopause, including lowered sex drive (unless they are on the ace-spectrum already), loss of body hair, and hot flashes. This will occasionally cause extra production in testosterone, which may caused more masculine or androgynous traits to develop.
Those with AFAB hypogonadism are usually diagnosed because they will not have started puberty.
Hypogonadism can be congenital or it can be acquired. Acquired hypogonadism may be caused by infections, radiation, certain autoimmune disorders, some chronic illnesses, severe stress, or damage to the pituitary gland (through drugs, radiation, or surgery.)
Hypogonadism may, in some cases, be caused by gene mutations, chromosomal abnormalities, and hormonal abnormalities. It can also be caused by other intersex variations.