Bone Abstracts

Severe generalised recessive dystrophic epidermolysis bullosa (RDEB) is a rare disorder resulting from loss of function mutations in the type VII collagen gene (COL7A1). Although RDEB is characterised by severe skin blistering and erosions following minor mechanical trauma, it is a multisystem disorder with pubertal delay and low bone mass as part of the many complications.

Children with RDEB have been described as having inadequate gains in bone density, so we hypothesised that pubertal delay may be a contributing factor. We sought to describe the prevalence of pubertal delay, low bone mass, vertebral compression fractures (VF) and scoliosis in children with RDEB aged 15-18y and compare this to the bone health of pre-pubertal RDEB children.

This was a retrospective, observational study of 40 patients with RDEB aged 7–8 and 15–18 years (n=20 in each group). Primary outcome measures were lumbar spine areal bone mineral density (aBMD), age adjusted z-score, VF, scoliosis and pubertal delay.

The aBMD (mean±S.D.) of children aged 7.8±0.5 years was 0.54±0.1 g/cm² with z-score of −1.8±1.1. 36% had VF and 11% had scoliosis.

This compared with aBMD of children aged 16.1±0.8 years of 0.72±0.2 g/cm² with z-score of −3.9±1.5. 40% had VF and 30% had scoliosis. 84% of these children had pubertal delay.

Despite an increase in aBMD (P<0.001) with age, there was a highly significant decrease in BMD z-score (P<0.0001). Surprisingly patients with VF did not have significantly different BMD z-scores from those without VF (P=ns, t-test).

Pre-pubertal children with RDEB have VF and low BMD z-scores that deteriorates with age. By the ages of 15–17, 84% of children have pubertal delay, which is likely to compound pre-existing poor bone health.

Despite early preventative interventions such as optimising nutrition, vitamin D supplementation and physiotherapy, complications including vertebral compressions and scoliosis are present from an early age and worsen over time. Early medical preventative interventions, such as bisphosphonate therapy should be considered in patients with RDEB.

Disclosure:: The authors declared no competing interests.