Development of the human gastrointestinal tract: Twenty years of progress

A combination of approaches has begun to elucidate the mechanisms of gastro intestinal development, This review describes progress over the last 20 yea rs in understanding human gastrointestinal development, including data from both human and experimental animal studies that address molecular mechanis ms, Rapid progress is being made in the identification of genes regulating gastrointestinal development. Genes directing initial formation of the endo derm as well as organ-specific patterning are beginning to be identified, S ignaling pathways regulating the overall right-left asymmetry of the gastro intestinal tract: and epithelial-mesenchymal interactions are;being clarifi ed. In searching for extrinsic developmental regulators, numerous candidate trophic factors have been proposed, but compelling evidence remains elusiv e. A critical gene that initiates pancreas development has been identified, as well as a number of genes regulating liver, stomach, and intestinal dev elopment. Mutations in genes affecting neural crest cell migration have bee n shown to give rise to Hirschsprung's disease, Considerable progress has b een achieved in understanding specific phenomena, such as the transcription factors regulating expression of sucrase-isomaltase and fatty acid-binding protein. The challenge for the future is to integrate these data into a mo re complex understanding of the physiology of gastrointestinal development.