We estimated the frequencies of phenotype (isoelectric focusing; IEF) vs, g
enotype (PCR/Hhal) discordance in a sample of an aged population (> 65 year
s). Both phenotype and genotype techniques have been used in the study of a
polipoprotein E (apoE) polymorphism in 125 elderly subjects.
The discordance between phenotype and genotype was unresolved in 11 (8.8%)
of the 125 unrelated subjects studied. We observed a significant associatio
n between the presence of the E4 allele and both Alzheimer's disease (chi (
2) = 13, p<0.001) and increased cholesterol concentration (Mann Whitney, p<
0.03). These relationships were not affected by the techniques used.
Our results indicate that transcriptional modulation and post-transductiona
l modifications in normal ageing and in aged-related diseases may explain i
n part discrepancies between gene analysis and protein characterisation.