Classic monogenic SAIDs include familial Mediterranean fever (FMF, caused by MEFV gene variants), TNF receptor-associated periodic fever syndrome (TRAPS, by autosomal dominant variants in the TNFRSF1A gene), cryopyrin-associated periodic syndromes (CAPS)/NLRP3-associated autoinflammatory disease (NLRP3-AID, by gain-of-function variants in the NLRP3 gene), and hyper-IgD syndrome (HIDS)/mevalonate kinase deficiency (MKD, by autosomal recessive variants in the MVK gene) (6). Here, MVK is linked to hyperimmunoglobulinemia D with periodic fever.