The protein encoded by this gene is a member of the fibroblast growth factor (FGF) family. FGF family members possess broad mitogenic and cell survival activities, and are involved in a variety of biological processes, including embryonic development, cell growth, morphogenesis, tissue repair, tumor growth, and invasion. This gene is located in a region on chromosome X, which is associated with Borjeson-Forssman-Lehmann syndrome (BFLS), making it a possible candidate gene for familial cases of the BFLS, and for other syndromal and nonspecific forms of X-linked mental retardation mapping to this region. Fibroblast growth factor 13 (FGF13) is probably involved in nervous system development and function. Alternative splicing of this gene results in several transcript variants encoding different isoforms with different N-termini.