A pilot clinical trial with losartan in Myhre syndrome

Introduction: Myhre syndrome (MS) is an ultra-rare disorder due to pathogenic variants in the SMAD4 gene that encodes a protein regulating the TGF-β pathway and extra-cellular matrix (ECM) homeostasis. Main clinical features of MS include thickening of skin and joint stiffness. Previous studies showed that losartan improved ECM deposition in MS fibroblasts. Materials and methods: Four molecularly confirmed MS subjects (mean age 23.8 ± 17 years) were evaluated for: (a) skin thickness by Rodnan score, (b) joint range of motion (ROM) by goniometry, and (c) speckle-tracking echocardiogram. Following baseline evaluations, three MS individuals received losartan for 12 months and pre-defined endpoints were monitored after 6 and 12 months of treatment. Results: At baseline, Rodnan scores were increased, joint ROM was reduced, and speckle-tracking echocardiogram revealed reduced myocardial strain. In three MS subjects, improvements in skin thickness, joint ROM and to a lesser extent of myocardial strain, were observed after 6 and 12 months of losartan treatment. Conclusions: Although further long-term controlled clinical trials with a larger number of affected individuals are needed, the present study suggests that losartan might improve skin, joint and heart abnormalities of MS.