The critical role for FGFR signaling in human SGs is evident by haploinsufficiency of either FGFR2b or one of its major ligands, FGF10, which leads to two rare genetic diseases, aplasia of lacrimal and salivary glands (ALSG: MIM #180929) and lacrimo-auriculo-dento-digital syndrome (LADD: MIM #149730)8. The gene discussed is FGF10; the disease is LADD syndrome.