Determinants of bone density and height in women with Androgen insenstivity,46XY Gonadal dysgenesis and 46XX Gonadal dysgenesis
S Trikudanathan & G Conway
Low bone density in women with androgen insensitivity syndrome [AIS] has been attributed to both androgen and oestrogen deficiency. Tall stature in women with AIS has been attributed to the presence of the Y chromosome and to delayed closure of the epiphyses due to relative sex steroid deficiency. In order to gain greater insight into these interactions we have compared bone density and height in four groups of women-27 women with AIS, 15 women with 46XY gonadal dysgenesis, 25 women with 46XX gonadal dysgenesis and 57 normal controls. Oestrogen use was recorded as age of starting HRT and cumulative oestrogen deficient years.
Women with 46XY karyotype were 6 cm taller than those with 46XX.When controlled for height, bone mineral density [BMD] was significantly reduced and similar in each of the three study groups AIS 84 percent of control, 46XY gonadal dysgenesis 84 percent and 46XX gonadal dysgenesis 85 percent. In the 46XY women oestrogen use and age of gonadectomy had no effect on BMD. Interestingly, in both AIS and 46XY
gonadal dysgenesis, age of gonadectomy positively correlated with height [AIS,r=0.57,p=0.03;46XYgonadal dysgenesis,r=0.58,p=0.02].
Timings of oestrogen use and gonadectomy have no impact on bone density in women with AIS.Androgen deficiency remains a contributing factor to low BMD in all three groups. The association between age of gonadectomy and height is likely to be an epiphenomenon of late presentation and suggests that both androgen and oestrogen deficiency contribute to tall stature in 46XY women.