Familial Mediterranean fever (FMF) is an autosomal recessive disease characterized by recurrent attacks of fever, synovitis, peritonitis, or pleurisy. Some patients eventually develop systemic amyloidosis. The biochemical cause of the disease is unknown. We have conducted a genome-wide search for the FMF locus using 125 different DNA markers and mapped the FMF gene to the short arm of chromosome 16. The study was performed on 35 Israeli families primarily of North African and Iraqi origin. For the five markers D16S82 (p41-1 Sacl), D16S80 (24-1 Taq1), D16S84 (pCMM65 Taq1), D16S83 (pEKMDA2-1 Rsal), and HBA (5'HVR Rsal) we obtained maximum lod scores of 2.72 (theta = 0.08), 10.34 (theta = 0.04), 9.66 (theta = 0.050, 9.35 (theta = 0.03), and 14.31 (theta = 0.08), respectively. Multipoint analysis with HBA and D16S84 defined as a fixed loci gave a maximum lod score of 19.86 centromeric to D16S84. Crossovers defined by these markers place the FMF gene in an area of approximately 5 cM between D16S80 and D16S84. Other genes mapped to this area (16p13.3) include phosphodiesterase IB (PDE1B), hydroxyacyl-glutathione hydrolase (HAGH), phosphoglycolate phosphatase (PGP), and the gene that causes adult polycystic kidney disease (PKD1). None of these genes bear an obvious pathophysiological relationship to FMF. Using additional markers from this region we hope to localize more precisely the FMF gene and to offer the possibility of prenatal diagnosis in selected cases. Our ultimate goal is to isolate and characterize the FMF gene.