Hirschsprung DiseaseDuodenoscopyCrohn DiseaseProto-Oncogene Proteins c-retEnteric Nervous SystemSOXE Transcription FactorsGlial Cell Line-Derived Neurotrophic Factor ReceptorsReceptor, Endothelin BEndothelin-3Waardenburg SyndromeReceptor Protein-Tyrosine KinasesMicrocephalyGlial Cell Line-Derived Neurotrophic FactorMultiple Endocrine Neoplasia Type 2aNeural CrestFaciesPenetranceMutationReceptors, EndothelinCarcinoma, MedullaryHigh Mobility Group ProteinsConsanguinityRectumIntellectual DisabilityDrosophila ProteinsAbnormalities, MultipleProto-Oncogene ProteinsHaplotypesNerve Growth FactorsGerm-Line MutationSyndromePedigreePolymorphism, Single-Stranded Conformational