FGFR2 alterations, which tend to cluster in iCCA, and HER2 overexpression, which is frequently observed in eCCA and GB, share common downstream signaling components, such as the Ras/Raf/MEK/ERK pathway, the PI3K/AKT/mTOR pathway, and the JAK/STAT pathway [106,107]. The gene discussed is ERBB2; the disease is infantile convulsions and choreoathetosis.