Pseudoxanthoma Elasticum – Also a Lung Disease? The Respiratory Affection of Patients with Pseudoxanthoma Elasticum

BACKGROUND Pseudoxanthoma elasticum (PXE) is an autosomal-recessive mineralisation disorder caused by loss of function mutations in the ABCC6 Gen. Histological findings and data of an autopsy of a PXE-patient suggest a possible pulmonal calcification. So far, there exists no clinical data whether PXE patients actually are at high risk of developing pulmonary disorder. METHODS In a cross-sectional study, 35 PXE patients and 15 healthy controls underwent a pulmonary function testing, including spirometry, body plethysmography and carbon monoxide diffusing test. Additionally, PXE patients completed a COPD-Assessment-Test (CAT). RESULTS We observed in PXE patients normal values for predicted vital capacity (VC%; 96.0±13.0%), predicted total lung capacity (TLC%; 98.2±12.0%) and predicted forced expiration volume (FEV1%; 102.5±15.6%), whereas compared to healthy controls the PXE group showed significant diminished values for carbon monoxide diffusing capacity (DLCO, 7.2 ±1.4mmol/min/kPa vs. 8.6 ±1.5 mmol/min/kPa; p = 0.008) and predicted carbon monoxide diffusing capacity (DLCO%; 79.7±11.5% vs. 87.2±6.6%; p = 0.008). 11/35 (31.4%) PXE patients showed pathological DLCO% values under 75% (68.5%±5.4%). CONCLUSION PXE patients demonstrated a regular lung function testing, but nevertheless they had impaired CO diffusing parameters, which might be associated with a preclinical state of an interstitial lung disease and a risk for restrictive ventilation disorders.