PAA has a high incidence in the German Shepherd, being a primary and hereditary process (Pancreatic Acinar Atrophy).
Another primary cause is Congenital Pancreatic Hipolasia.
It is also common to find PAA secondary to chronic pancreatitis, where the functional tissue is replaced by a fibrous tissue (non-secretory).
PAA secondary to chronic pancreatitis is the most common condition in cats. There are also situations of PAA associated to severe protein malnutrition.