Genetic typing of alpha1-antitrypsin by immunofixation electrophoresis, identification of subtypes of Pi M.

Prolonged electrophoresis in alkaline agarose gels, followed by immunofixation, is a valuable addition to acid starch gel electrophoresis and isoelectric focusing for the genetic phenotyping of alpha1-antitrypsin. This technique is helpful in clarifying certain variants and in ascertaining types in serum and amniotic fluid samples with secondary changes. In addition, heterogeneity may be detected within the variants found at pH 4.95, analogous to hemoglobin polymorphism. Two "new" variants, PiMLamb and PiMBaldwin, have been detected by a combination of immunofixation electrophoresis and acid starch gel electrophoresis.