%0 Journal Article %T Treatment with low %A E Spiekerkoetter %A F Droege %A H Gall %A HA Ghofrani %A K Tello %A K Wirsching %A KE Gamen %A LM Deubner %A M Hecker %A MJ Richter %A N Sommer %A R Schmiedel %A S Pullamsetti %A U Geisthoff %A W Seeger %J Pulmonary Circulation %@ 2045-8940 %D 2019 %R 10.1177/2045894018805406 %X Pulmonary arterial hypertension (PAH) can be found in patients suffering from a loss-of-function mutation of the gene encoding for the activin receptor-like kinase 1 (ALK-1), a bone morphogenetic protein (BMP) type 1 receptor. Interestingly, ALK-1 mutations also lead to hereditary hemorrhagic telangiectasia (HHT), an autosomal dominant disease characterized by arteriovenous malformations (AVMs) leading to potentially life-threatening bleeding complications such as epistaxis. Current therapeutic options for both diseases are limited and often only temporary or accompanied by severe side effects. Here, we report of a patient with a mutation of the ALK-1 gene suffering from both HHT and PAH. Recently, it was shown that tacrolimus increased ALK-1 signaling and had beneficial effects in selected end-stage PAH patients. We thus hypothesized that treatment with tacrolimus may prevent disease progression in this patient. Surprisingly, treatment with low-dose tacrolimus dramatically improved his HHT-associated epistaxis but did not attenuate progression of PAH %K ALK-1 mutation %K FK506 %K Morbus Osler %K tacrolimus %K VEGF %U https://journals.sagepub.com/doi/full/10.1177/2045894018805406