Male, 53‐year‐old patient, affected by MGUS IgM/κ with a 7 years‐long follow‐up, who was referred to the emergency room because of rapid increase of body weight, severe oedema and proteinuria of 25 g/24 h associated to marked serum hypoalbuminemia of 14 g L−1. This evidence concerns the gene CD40LG and Hypoalbuminemia.