ESPE Abstracts (2016) 86 P-P1-130

Triple X Syndrome: An Evaluation of Bone Mineral Status and Metabolism

Stefano Stagia, Perla Scalinia, Mariarosaria Di Tommasob, Maria Parpagnolia, Silvia Pacia, Fabrizio Masoni f, Francesco Chiarellic, Alberto Verrottid, Silvia Guarduccie, Sabrina Giglioe, Silvia Romanoe & Maurizio de Martinoa

aHealth Science Department, University of Florence, Anna Meyer Children’s University Hospital, Florence, Italy; bDepartment of Health Sciences, University of Florence, Careggi Hospital, Florence, Italy; cDepartment of Paediatrics, Universty of Chieti, Chieti, Italy; dDepartment of Paediatrics, University of L’Aquila, L’Aquila, Italy; eGenetics and Molecular Medicine Unit, Anna Meyer Children’s University Hospital, Florence, Italy; fPaediatric Unit, Empoli Hospital, Empoli, Italy

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 7.7–15.9 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.