Failure to thrive. How about Hirschsprung's disease?
D003937:Diagnosis, Differential; D006130:Growth Disorders / Q000175:diagnosis; D006801:Humans; D007223:Infant; D007228:Infant Nutrition Disorders / Q000175:diagnosis; D007231:Infant, Newborn; D008297:Male; D008531:Megacolon / Q000175:diagnosis*