IDH1 and infantile convulsions and choreoathetosis: A similar stratification of iCCA subtypes based on mutational profiling was reported by Akita et al., who observed that SMAD4 and MDM2 mutations were restricted to pCCA and large duct type iCCA, whereas BAP1 and IDH1 were more specific to the small duct type iCCA [42], associated with lower CA19-9 levels [34,42].