Family with sequence similarity 9 member B (FAM9B)

Family with sequence similarity 9 member B (FAM9B) is a protein-coding gene located on the X chromosome[1][2][4][5][6]. Its expression is largely restricted to the testis, specifically in the nuclei of primary spermatocytes, where it colocalizes with components of the synaptonemal complex—a structure essential for pairing and recombination between homologous chromosomes during meiosis[1]. FAM9B is implicated in the formation and function of the meiotic machinery, as well as in proper DNA recombination events critical for gametogenesis and fertility[1][2]. Genetic studies have indicated that variants proximal to the FAM9B gene region are associated with differences in circulating testosterone levels in men, suggesting a broader influence on systemic androgen regulation and male reproductive traits[1]. Although FAM9B is linked to reproductive function, it is not currently recognized as a classical drug target or involved in established therapeutic pathways, with no drugs known to interact directly with the gene or protein[1][2][6].

Other names

TEX39BFAM9B_HUMAN (UniProt)Gene ID 171483

None established; no drugs target FAM9B directly