Familial Mediterranean fever (FMF) is caused by mutations of MEFV [6, 7]; mevalonate kinase deficiency (MKD), by mutations of the mevalonate kinase gene (MVK) [8, 9]; tumor necrosis factor (TNF) receptor‐associated periodic fever syndrome (TRAPS), by mutations of type I TNF receptor (TNFSRF1A) [10]; and cryopyrin‐associated periodic syndromes (CAPS), by mutations of NLRP3 [11, 12]. Here, MVK is linked to hyperinsulinemic hypoglycemia, familial, 4.