Failure to thrive, nutritional edema, and hypoproteinemia with normal sweat electrolytes were features of 2 affected male infants reported by Townes (1965) and Townes et al. (1967). The infants had deficiency of trypsinogen (276000). A male sib of ... Failure to thrive, nutritional edema, and hypoproteinemia with normal sweat electrolytes were features of 2 affected male infants reported by Townes (1965) and Townes et al. (1967). The infants had deficiency of trypsinogen (276000). A male sib of the first patient reported by Townes (1965) had died, apparently of the same condition. Morris and Fisher (1967) reported an affected female who also had imperforate anus. Townes (1972) noted that the clinical picture in enterokinase deficiency (226200) is closely similar; however, the defect is not in the synthesis of trypsinogen but in the synthesis of the enterokinase (606635), which activates proteolytic enzymes produced by the pancreas.