Bone Abstracts

Objective: Low bone mass is a frequent and early complication of subjects with Rett syndrome. As a consequence of the low bone mass Rett girls are at an increased risk of fragility fractures. The frequent occurrence of osteopenia raises questions regarding the direct influence of MECP2 gene mutations on bone growth and attainment of peak bone mass. It is well known that other critical factors such as the use of anticonvulsant drugs, the presence of scoliosis, the nutrition status, the low levels of 25OHD and the ambulatory impairment influence the attainment of peak bon mass in Rett subjects.

This study aimed to investigate the long-term influences of mobility on bone status in girls with Rett syndrome

Methods: In 47 girls with Rett syndrome, serum calcium, bone alkaline phosphatase, 25-hydroxyvitamin D and quantitative ultrasound (QUS) parameters at phalanxes by Bone Profiler-IGEA (amplitude dependent speed of sound: AD-SoS and bone transmission time (BTT)) were measured at baseline and after 5 and 10 years. The subjects were divided into two groups: non ambulatory (n=22) and ambulatory (n=25).

Results: At baseline both AD-SoS and BTT values were lower in non ambulatory with respect to ambulatory subjects, but the difference was not statistically significant. Non ambulatory subjects presented a significantly (P<0.05) later onset of age at menarche and lower birth weight with respect to the ambulatory subjects. BMI was significantly lower in non ambulatory subjects than in ambulatory subjects at each time point. At the 5-year follow up both ambulatory and non ambulatory Rett subjects presented a similar reduction in both AD-SoS and BTT. Also at 10-year follow up both non ambulatory and ambulatory subjects showed a significant reduction in AD-SoS (−4.7% P<0.05; and −3.4% P=n.s. respectively) and in BTT (−54% P<0.05; and −41% P=0.05 respectively) with respect to baseline.

Conclusion: In conclusion this longitudinal study suggests the usefulness of AD-SoS and BTT in the monitoring of bone status in Rett patients. In particular we found that QUS parameters are markedly decreased in non ambulatory subjects and that nutritional status play a key role in the progressive deterioration of bone status.

Disclosure: The authors declared no competing interests.