Normal Tempo of Bone Formation in Turner Syndrome despite Signs of Accelerated Bone Resorption

Aims: To evaluate area bone mineral density (aBMD) and volumetric BMD (vBMD) by dual-energy X-ray absorptiometry, and relations to bone markers and hormones in adolescent women with Turner syndrome (TS). Methods: Cross-sectional study in TS patients (n = 37, 16.7 ± 3.4 years) and control group (n = 49), assessed by dual-energy X-ray absorptiometry, bone markers and hormones. TS patients were divided into a young group receiving ('ongoing') GH (n = 15) and an older group previously receiving ('previous') GH (n = 22). Results: vBMD(spine) was similar in 'ongoing GH' TS, but higher in 'previous GH' TS, compared to controls. vBMD(hip) was lower in 'ongoing GH' TS, but similar in 'previous GH'. z scores for aBMD were uniformly reduced in 'ongoing TS', but near-normalized in 'previous GH' TS. Bone formation and resorption markers were increased in 'ongoing GH' TS, while 'previous GH' TS had elevated bone resorption markers. Conclusion: BMD increased in parallel with age in TS patients receiving optimal estradiol replacement therapy and GH according to consensus guidelines, and in controls. Young TS undergoing pubertal induction and still receiving GH have lower z score BMD than older TS patients receiving hormonal replacement therapy, where a near-normalization of BMD was achieved. TS patients previously receiving GH showed signs of increased bone resorption.