vitamin deficiencies; drug and alcohol exposures; and viral, chemical, and external physical events may contribute to the development of EA.

Notochord is a flexible, rod shaped body found in embryos of all chordates. It is composed of cells derived from the mesoderm and defines the primitive axis of the embryo.] abnormalities, desynchronous Lack of synchrony, as in brain waves.] esophageal mesenchymal loosely organized connective tissue present in the embryo regardless of origin and epithelial. In biology and medicine, epithelium is a tissue composed of layers of cells that line the cavities and surfaces of structures throughout the body growth rates, neural crest transient component of the ectoderm, is located in between the neural tube and the epidermis or the free margins of the neural folds of an embryo during neural tube formation cell involvement, and incomplete tracheoesophageal separation resulting from a lack of apoptosis a form of programmed cell death in multicellular organisms are some of the conditions theorized for EA embryogenesis. Similarly, incomplete tracheoesophageal septation, lateral ridge fusion failure, and tracheal and esophageal proximity have been suggested as possible explanations for the origin of TEF. In addition, vascular insufficiencies genetic factors; vitamin deficiencies; drug and alcohol exposures; and viral, chemical, and external physical events may contribute to the development of EA.