MVK and hyperinsulinemic hypoglycemia, familial, 4: Mevalonate Kinase Deficiency (OMIM #260920; MKD) is a rare and neglected disease, due to mutations in the mevalonate kinase gene (MVK) coding for mevalonate kinase (MK), an enzyme of the mevalonate pathway for the biosynthesis of cholesterol and non-sterol isoprenes [39,40].