The duodenal channel may be underdeveloped (duodenal hypoplasia), narrowed (duodenal stenosis), or the duodenum channel may not be properly formed (duodenal atresia).
As with Type III malformation, many neurologists do not consider this a Chiari malformation but rather cerebellar hypoplasia (underdevelopment).
However, about 50 percent of fetuses with CDH do not survive after birth because their lungs are too small (pulmonary hypoplasia).
Delayed eruption of teeth and enamel hypoplasia and an increased incidence of postnatal infections are frequently seen.
Large CCAMs can limit lung development, causing pulmonary hypoplasia.
Disorders such as Apert's Syndrome can cause midface hypoplasia.
This condition is known as cerebellar hypoplasia.