A 69-year-old male with a history of monoclonal gammopathy of unknown significance (MGUS) IgM lambda was first evaluated for dyspnoea on exertion in 2014. At that time, this was attributed to mild pulmonary hypertension caused by diastolic heart failure of unknown origin. One year later his dyspnoea was rapidly progressive and he was re-evaluated. Physical examination showed strikingly thin and brittle fingernails on both hands, with longitudinal ridging (figure 1). Echocardiography and cardiovascular magnetic resonance were performed.