Apolipoprotein E phenotypes and genotypes as determined by polymerase chain reaction using allele-specific oligonucleotide probes and the amplification refractory mutation system in children with insulin-dependent diabetes mellitus.

The frequency of apolipoprotein E (apo E) phenotypes and genotypes due to allelic variation at amino acids 112 and 158 was analysed in 50 children with type I diabetes. Phenotypes were determined by isoelectric focusing and genotypes by the technique of polymerase chain reaction using allele-specific oligonucleotide probes (PCR/ASO) and the amplification refractory mutation system (ARMS). Discrepancies between phenotypes and genotypes as assigned by PCR/ASO were observed in 12 (24%) cases and by ARMS in eight (16%) cases. Results revealed the apo E3/3 genotype, as assigned by ARMS, to be the most frequent one (70%), followed by apo E3/4 in 16%, apo E2/2 in 2%, apo E2/3 in 8%, apo E2/4 in 2% and apo E4/4 in 2% of the cases. Apo E3/4 genotype and phenotype were more frequently present in the children with type I diabetes as compared with the diabetic adults previously reported on.