Mucopolysaccharidoses in the Scandinavian countries: incidence and prevalence

Aim: The aim of this study was to estimate the incidence and prevalence of mucopolysaccharidoses (MPS disorders) in Scandinavia. Methods: The retrospective period used for the incidence study covered the period from 1975 to 2004 in Sweden and Denmark and from 1979 to 2004 in Norway. Prevalence was derived from the number of MPS patients alive as of December 31, 2007. Results: The incidence of all MPS disorders was 1.75 cases in Sweden, 3.08 cases in Norway and 1.77 cases in Denmark per 100 000 newborns. The incidence of MPS I was the most common in all three countries, with 0.67, 1.85 and 0.54 cases per 100 000 newborns, respectively; for MPS 11, numbers were 0.27, 0.13 and 0.27, respectively. For patients with other MPS disorders the incidence varied widely. The prevalence for all MPS disorders was 4.24, 7.06 and 6.03 per 1 000 000 inhabitants in Sweden, Norway and Denmark, respectively. Conclusion: From three Scandinavian countries the incidence of MPS disorders is retrospectively evaluated for 25 years in Norway and 30 years in Sweden and Denmark. Incidence and prevalence studies of lysosomal disorders are prerequisites for cost benefit calculations in the face of newly developed and expensive therapies in the future.