Endocrine Abstracts

JOINT1460

Introduction: Cleidocranial dysplasia (CCD) primarily affects intramembranous ossification, causing hypoplastic/aplastic clavicles, delayed cranial suture closure and dental abnormalities. Endochondral ossification can also be altered with impairment of bone mineral density (BMD), but data are limited.

Methods: Three databases (Embase, Medline, Cochrane) were systematically screened for publications assessing BMD in CCD. We reviewed clinical records of our CCD cohort. Collected data included DEXA assessments (lumbar spine [LS]-BMD, total body less head [TBLH]-BMD), evidence of vertebral (VF) or long-bone fractures and bisphosphonate treatments. LS-BMD of patients with height <-2/>2 SDS was adjusted using BMAD.

Results: Literature review identified 29 patients (51.7% females, 62.1% children). DEXA scan was performed in 86.2% cases, Qualitative-Ultrasound and X-Rays in the remaining. The average LS-BMD Z-score was -1.91 (±1.16), with paediatric population displaying lower scores (-2.26±1.05), particularly in females (-2.53±1.14). Adults LS-BMD Z-score was -1.38 (±1.17). Fractures were reported in 27.6% patients. Our cohort consists of 30 paediatric patients. Twenty-four (75% males; 66.7% prepubertal; average-age 9.4 years, 5.2-17.2) had ≥1 DEXA scan performed. Median LS-BMD Z-score resulted -1.65 (IQR 1.84), being ≤-2 SDS in 41.7%. Similarly, TBLH-BMD Z-score was -1.75 (1.60) and ≤-2 SDS in 37.5%. Osteoporosis was diagnosed in 16.7%, always VF-related and treated with bisphosphonates. Two patients reported trauma-related long-bone fractures.

Discussion: Both literature and our cohort showed low LS-BMD Z-scores. Although the lack of height-adjustment of published cases may underestimate LS-BMD, our cohort supports these findings, as 41.7% had Z-score ≤-2 SDS. Additionally, LS-BMD was significantly lower in prepubertal patients, highlighting pubertal influence on BMD. Even TBLH-BMD resulted low: interestingly, paediatric females showed significant lower Z-scores than males. However, the lack of height-adjustment might have overestimated the Results. Although identification of pathological fractures in published cases is hindered by the lack of details, 16.7% of our cohort met osteoporosis criteria. Finally, there was no association between LS-/TBLH-BMD Z-scores and VF: these parameters might not independently predict VF.

Conclusion: Our work emphasizes the need of screening programs for low BMD in CCD patients. DEXA assessment and bisphosphonate treatment should be considered in paediatric age, with a yearly follow-up monitoring, aiming prevention and treatment of osteoporosis.