1. ¹Department of Dermatology and Cutaneous Biology, Jefferson Medical College, Jefferson Institute of Molecular Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
2. ²Department of Biochemistry and Molecular Biology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, USA

Correspondence: Dr Jouni Uitto, Department of Dermatology and Cutaneous Biology, Jefferson Medical College, Jefferson Institute of Molecular Medicine, Thomas Jefferson University, 233 S. 10th Street, Suite 450 BLSB, Philadelphia, Pennsylvania 19107, USA. E-mail: Jouni.Uitto@jefferson.edu

Received 26 August 2008; Revised 20 October 2008; Accepted 31 October 2008; Published online 1 January 2009.

Abstract

Pseudoxanthoma elasticum (PXE) is an autosomal recessive multisystem disorder characterized by ectopic connective tissue mineralization, with clinical manifestations primarily in the skin, eyes, and cardiovascular system. There is considerable, both intra- and interfamilial, variability in the spectrum of phenotypic presentation. Previous studies have suggested that mineral content of the diet may modify the severity of the clinical phenotype in PXE. In this study, we utilized a targeted mutant mouse (Abcc6^-/-) as a model system for PXE. We examined the effects of changes in dietary phosphate and magnesium on the mineralization process using calcification of the connective tissue capsule surrounding the vibrissae as an early phenotypic biomarker. Mice placed on custom-designed diets either high or low in phosphate did not show changes in mineralization, which was similar to that noted in Abcc6^-/- mice on control diet. However, mice placed on diet enriched in magnesium (fivefold) showed no evidence of connective tissue mineralization in this mouse model of PXE. The inhibitory capacity of magnesium was confirmed in a cell-based mineralization assay system in vitro. Collectively, our observations suggest that assessment of dietary magnesium in patients with PXE may be warranted.