The purpose of the study was to investigate a possible connection between alpha-l-antitrypsin (A1AT) deficiency and familial epilepsy and mental retardation of possible congenital or genetic origin.The individuals were genotyped by using a two dimensional cross-electrophoretic procedure. The electrophoretic procedure involved isoelectric focusing on an acid-starch gel followed by immunoelectrophoresis. The control and experimental groups were then statistically compared to population norms by using the chi-square test. The 0.05 level of significance was established as the critical probability level for the nonacceptance of a connection.ResultsOf the 49 individuals in the control group, 46 had, a protease inhibitor (Pi) genotype of PiMM 1 , and there was 1 each of the Pi MF, Pi MS, and Pi Mz genotypes. Of the 50individuals in the familial epilepsy experimental group, 43 were genotyped as PiMM, 2 as PiMS, and 5 as PIMF. Of the 16 individuals in the mental retardation experimental group, 14 were genotyped as PiMM, 1 as PiMS, and 1 as PiMF.The probability of reoccurrence for the various groups were: control - 0.3 to 0.5; familial epilepsy - 0.3 to 0.5; and mental retardation - 0.7 to 0.8.Conclusions1. The applicability of starch gel electrophoresis in a clinical setting is questionable because of cost, length of time required, and difficulty in handling.2. The control group demonstrated no statistical variation in the 1AT frequency from general population norms.3. The familial epilepsy experimental group showed no statistical evidence linking it to abnormal A1AT genotypes.4. The mental retardation experimental group demonstrated no statistical evidence linking it to abnormal A.1 AT genotypes.