Mevalonate kinase deficiency

Mevalonate kinase deficiency, abbreviated MKD, is an autosomal recessive metabolic disorder that disrupts the body's production of cholesterol and isoprenoids. It is rare overall, but a high frequency is observed in Northern European regions. The enzyme involved, mevalonate kinase, converts mevalonate into mevalonate-5-phosphate, and a pathogenic variant in the gene that encodes it reduces or removes the enzyme's activity, so mevalonic acid can build up in the body and appear at high levels in the urine. Severity depends on how much activity is lost: hyperimmunoglobulinemia D syndrome, first described as HIDS in 1984, is the less severe but more common form, and mevalonic aciduria is the more severe but rarer form.