The duodenal channel may be underdeveloped (duodenal hypoplasia), narrowed (duodenal stenosis), or the duodenum channel may not be properly formed (duodenal atresia).
Children are more likely to suffer sports injuries than adults since a child's vulnerability is heightened by immature reflexes, an inability to recognize and evaluate risks, and underdeveloped coordination.
Therefore, the following discussion of symptoms applies primarily to affected individuals in the past and in some underdeveloped countries as of the early 2000s.
During a physical examination, the doctor looks for underdeveloped breasts and genitalia, webbed neck, short stature, low hairline in back, simian crease (a single crease in the palm), and abnormal development of the chest.
The lungs, digestive system, and nervous system (including the brain) are underdeveloped in premature babies and are particularly vulnerable to complications.