This family contains sequences bearing similarity to a region of GSG1 (Swiss:Q9Z1H7), a protein specifically expressed in testicular germ cells [1]. It is possible that overexpression of the human homolog may be involved in tumourigenesis of human testicular germ cell tumours [1]. The region in question has four highly-conserved cysteine residues.

1: Mapping of six germ-cell-specific genes to mouse chromosomes. Matsui M, Ichihara H, Kobayashi S, Tanaka H, Tsuchida J, Nozaki M, Yoshimura Y, Nojima H, Rochelle JM, Nishimune Y, Taketo MM, Seldin MF; Mamm Genome 1997;8:873-874. PMID:9337410