Table 1

Characteristics of the cohorts for the analysis of single nucleotide polymorphisms (SNPs) in SPP1 and LTBP4 genes

LeidenFerraraMontpellierNewcastleLondon
SPP1
Patients65431076853
Wheelchair dependent47431074546
Mean birth year19931989198919951995
Steroid use
 Yes271373421
 No38301003432
Mean age of ambulation loss in non-ambulant patients (years)
 Overall9.610.19.510.510.8
 Steroid treated10.511.59.812.111.6
 Non-steroid treated9.29.49.59.710.3
SNP frequencies
 TT52.365.161.764.762.3
 GT/GG47.734.938.335.337.7
LTBP4
Patients6343386952
Wheelchair dependent4643384645
Mean birth year19931989198719951995
Steroid use
 Yes271323420
 No3630363532
Mean age of ambulation loss in non-ambulant patients (years)
 Overall9.610.19.510.610.8
 Steroid treated10.511.58.612.111.7
 Non-steroid treated9.19.49.69.810.3
Haplotype frequencies
 VTTT52.049.351.247.641.9
 IAAM30.628.829.837.447.0
 Other17.421.919.015.011.1