Background: However, no study has considered the effect of a supernumerary X chromosome on bone mineral status and bone metabolism.
Objective and hypotheses: To evaluate bone mineral status and metabolism in a cohort of patients with nonmosaic triple X syndrome.
Method: Nineteen girls (median age 10.9, range 7.715.9 years) with nonmosaic triple X syndrome were cross-sectionally studied and compared to an age- and body-size-matched control group. We evaluated ionised and total calcium, phosphate, parathyroid hormone (PTH), 25-hydroxyvitamin D (25[OH]D), 1,25-dihydroxyvitamin D, osteocalcin, bone alkaline phosphatase levels, and urinary deoxypyridinoline concentrations. We also calculated the phalangeal amplitude-dependent speed of sound (AD-SoS) and the bone transmission time (BTT) z-scores.
Results: Triple X patients showed significantly reduced AD-SoS (P<0.005) and BTT z-scores (P<0.0001) than the controls. These results persisted when we divided the sample into prepubertal and pubertal patients (P<0.05). Triple X patients also had significantly lower calcium ionised (P<0.005), and higher phosphate (P<0.0001) and PTH (P<0.0001) levels. However, triple X patients also showed significantly reduced 25(OH)D levels (P<0.005). AD-SoS and BTT z-scores values were significantly inversely correlated with age (P<0.005), PTH (P<0.005), and 25(OH)D (P<0.005).
Conclusion: Subjects with nonmosaic triple X syndrome exhibit a significant reduction in bone mineral status and showed an impaired bone metabolism similarly to other X polisomy such as Klinefelter syndrome, hypothesizing the presence of a primary bone deficit. This suggests the need to closely monitor these subjects.
10 - 12 Sep 2016
European Society for Paediatric Endocrinology