Turner syndrome (45,X) is the most common karyotypic abnormality causing gonadal failure and primary amenorrhea. Amenorrhea is the result of accelerated atresia of the follicles. The fibrotic ovaries are called streak ovaries. Associated stigmata with Turner syndrome include Gonadal Failure Sho stature Webbed neck, Shield chest, Cubitus valgus low hair line high arched palate multiple pigmented nevi Sho fouh metacarpals Cardiac (30% have coarctation of the aoa), Renal (especially horseshoe kidney), Autoimmune (thyroiditis) Androgen insensitivity is a genotypic male with functional testes but the androgen made by the testes is not recognised by the end organs and hence they reach the periphery and conve to estrogens. This leads to external feminisation. Swyer syndrome is much rarer. This is characterised non functional testes. Hence uterus cervix tubes and upper 4/5th of vagina is made. Lower 1/5th vagina is made by the urogenital sinus.This is the 46xy 'female' .Since there is no working androgens, there is no maculinisation, and also no feminisation since there is no estrogen production. This is a much lesser feminine woman as compared with testicular feminization syndrome