Defective protein prenylation is a diagnostic biomarker of mevalonate kinase deficiency

Mevalonate kinase (MVK) deficiency (MKD) is a rare, autosomal-recessive autoinflammatory disease that presents in its milder form as hyper-IgD syndrome (HIDS), and in the most severe cases as mevalonic aciduria (MVA).1 It is widely assumed that the inflammatory symptoms of MKD are caused by defective protein prenylation owing to hypomorphic mutations in MVK. Prenylation is a posttranslational modification of proteins, particularly small GTPases, with isoprenoid lipids that are generated via the mevalonate biosynthetic pathway2 (Fig 1, A).