FGF8 and cleft lip: Since the ISM1 expression pattern is similar to and belongs to the same expression group as Fgf-8, it is expressed in MHB, ear substrate, maxilla, mandible, periorbital, and other sites important for craniofacial development,  including branchial arch 1 (BA1) which gives rise to the maxilla, the structure that is associated with cleft lip and/or palate (Osório et al. 2014; Pera et al. 2002).