A congenital defect of the vasculature such that there is a shunt (by-pass) of blood directly from the portal vein to the vena cava (i.e., the blood from the portal vein is not filtered through the liver).

Congenital disorder of glycosylation type IIaa (CDG2AA) is an autosomal recessive disorder characterized by infantile mortality due to liver disease, skeletal abnormalities, and protein glycosylation defects (Linders et al., 2021). For an overview of congenital disorders of glycosylation, see CDG1A (212065) and CDG2A (212066).