Article title
Jefferson AL, Woodhead HJ, Fyfe S, Briody J, Bebbington A, Strauss BJ, Jacoby P, Leonard H. Bone mineral content and density in Rett syndrome and their contributing factors. Pediatric Research. 2011;69(4):293-8. Download snapshot, see article abstract.
Background
Girls and women with Rett syndrome are at an increased risk of having a fracture. The risk of having a fracture has been shown to be strongly linked to bone mass and density. We therefore wanted to assess bone mineral content and bone mass density in girls and women in our Australian study. We also wanted to investigate whether specificMECP2mutations, epilepsy, body mass index, onset of puberty and mobility level had any influence on bone mineral content, bone mass or density.
What we did
We arranged for bone density scans to be undertaken in 97 girls and women in the Australian Rett Syndrome Study aged between 4-32 years and combined this with information collected through questionnaires. Using a densitometry machine we measured the bone mineral content and density of the cervical region (neck), lumbar spine (lower back), and total body (measures all bones in the body and calculates an average). Body composition, such as lean tissue mass (amount of muscle) and fat mass, was also assessed.
What we found
We found that the bone mass and density were very low compared with females of the same age. However, although still low, these measurements improved when comparing the results with females of the same height as those with Rett syndrome. Those in the older age groups had lower bone mass and density, as did those with epilepsy and decreased mobility. We also found that girls and women who had the p.R168X or p.T158M mutations had lower bone mass and density compared to other mutation types. Furthermore there was a decrease in the amount of muscle in these girls, which was associated with lower bone mass and density measurements.
What does it mean
Increasing the amount of muscle has the potential to improve bone mass and density in all individuals. Therefore increasing physical activity levels, where possible, would be the best approach to increasing bone mass and density in girls with Rett syndrome. Maintenance of adequate calcium in the diet and Vitamin D levels (mainly produced by sunlight exposure) are also recommended, as they are both strong contributors to healthy bones.
What next
It is important to find out how bone density and mass change over time in Rett syndrome and further research to do this is underway. In addition, we are now in the process of developing clinical guidelines directed at improving the diagnosis, management and treatment protocols of low bone density in Rett syndrome.