The putative fifth human serum amyloid A protein (SAA)-related gene "SAA5" is defined by SAA3.

The four well characterised members of the human serum amyloid A protein (SAA) gene family are clustered on chromosome 11p15.1. The acute phase SAA genes, SAA1 and SAA2, are hyperinducible in response to inflammatory stimuli, whereas SAA4 is only minimally induced, and SAA3 is a pseudogene. We recently demonstrated that the GSAA4 sequence, reported by others (Sack, G.H. Jr. and Talbot, C.C. Jr., 1992. Biochem. Biophys. Res. Comm. 183, 362-366), and misidentified as corresponding to the SAA4 locus, maps to the 11p15 region and speculated that it may be in close proximity to a distinct fifth SAA locus: "SAA5". In this report we have used vectorette PCR in combination with direct sequencing and computer based homology searches of the nucleotide sequence databases to establish that the putative fifth SAA-related locus, "SAA5", is defined by SAA3 and therefore does not represent a distinct SAA gene.