Familial mediterranean fever (FMF) is an autosomal recessive hereditary disorder associated with mutations in the gene on chromosome 16 encoding the protein pyrine (marenostrine). Marenostrine is thought to stimulate the production of an inactivator of a chemotactic factor (possibly C5a). The mutations result in ongoing inflammation, a hallmark of FMF. DNA diagnosis of FMF is operational in Leiden University, the Netherlands, for one year now.