Low levels of oestrogen effect the HPG axis with no feedback to the anterior pituitary to inhibit the secretion of FSH and LH. FSH and LH are secreted at abnormal elevated levels. Improper levels of these hormones will cause a failure to initiate puberty, undergo menarche, and develop secondary sex characteristics. If sufficient functional ovarian tissue is present, limited menstrual cycles can occur.The pathogenesis of 46,XX gonadal dysgenesis is unclear, as it can manifest from a variety of dysregulations. Interruption during ovarian development in embryogenesis can cause 46,XX gonadal dysgenesis with cases of abnormalities in the FSH receptor
and mutations in steroidogenic acute regulatory protein (StAR protein) which regulates steroid hormone production. 46,XY gonadal dysgenesis
46,XY gonadal dysgenesis is characteristic of male hypogonadism with karyotype 46,XY.In embryogenesis, the development of the male gonads is controlled by the testis determining factor located on the sex-determining region of the Y chromosome (SRY). The male gonad is dependent on SRY and the signalling pathways initiated to several other genes to facilitate testis development.The aetiology of 46,XY gonadal dysgenesis can be caused by mutations in the genes involved in testis development such as SRY, SOX9, WT1, SF1, and DHH. If a single or combination of these genes are mutated or deleted, downstream signalling  is disrupted, leading to malformation of male external genitalia.SRY acts on gene SOX9 which drives Sertoli cell formation and testis differentiation. An absence in SRY causes SOX9 to not be expressed at the appropriate time or concentration, leading to a deficiency in testosterone and anti-Müllerian hormone production.
See also
(DoDI) 6130.03, 2018, section 5, 13f and 14m
Ovotestis
46 XX

References


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