The local calcification inhibitor matrix Gla protein in pseudoxanthoma elasticum

Objectives Recent studies have revealed the involvement of calcification inhibitory proteins in the pathogenesis of pseudoxanthoma elasticum (PXE). Design and methods We analyzed serum concentrations of the calcification inhibitor matrix Gla protein (MGP) in a large cohort of patients suffering from PXE (n = 101), 34 first-degree relatives and 67 healthy controls. Moreover, we determined the distribution of the two MGP promoter polymorphisms c.-7G>A and c.-138T>C in the three cohorts. Results We found significantly lower total MGP concentrations in the sera of PXE patients compared to healthy controls (p = 0.0002). Furthermore, higher serum MGP concentrations could be correlated with a later PXE onset. Analysis of MGP promoter polymorphism frequencies revealed one MGP haplotype to be a potential protective co-factor in PXE. Conclusions Our findings point to a role of the local calcification inhibitor MGP in PXE manifestation.