The TSSC4 (for tumor-suppressing STF cDNA 4) gene is located in the centre of a 1 Mb gene cluster which contains several imprinted genes; however in humans the TSSC4 gene is not imprinted [, ]. This same cluster is associated with the Beckwith-Wiedermann syndrome []. Proteins in the TSSC4 family are found in eukaryotes, and contain a conserved YSL sequence motif.