Pancreatitis-like isoamylase pattern in normal persons.

On the assumption that a rise in the pancreatic type isoamylases may not necessarily indicate underlying pancreatitis, genetic studies of human serum and urinary amylase isoenzymes have been performed with the use of electrophoresis. Although the preponderant increase in the two principal pancreatic isoamylases Amylase-1 and 2 has been accepted to be a specific index of pancreatic involvement, 1.68% of normal persons had Amylase-2 with an elevated amylase activity (named "Dominant Amylase-2") up to the same levels as the major isoenzymes. Results of pancreozymin-secretin test and other laboratory findings of these persons with Dominant Amylase-2 were all within normal ranges. Pedigree studies confirmed an autosomal dominant mode of inheritance for this variant. The important of serial determination and pedigree investigations has been shown to distinguish normal persons having Dominant Amylase-2 from patients with pancreatitis without elevated amylase activity. The existence of an inherited trait of pancreatitis-like isoamylase pattern in healthy individuals must be born in mind before coming to a conclusion when amylase isoenzymes are used for clinical medicine, though preponderance of the pancreatic type isoenzymes in serum and urine has been revealed to be a characteristic finding in pancreatitis. Knowledge of amylase genetic polymorphism provides a scientific basis for amylase isoenzyme interpretation.