Analysis of the APOE Alleles in Mental Retardation without Chromosome Anomaly / 대한해부학회지

ABSTRACT

APOE (apolipoprotein E) has been as a risk factor for Alzheimer's disease. Studies demonstrated that there was no significant differences in APOE distribution compared with controls and there was also a report showing a lower frequency of APOE E4 allele in an elderly Down's syndrome population than in a control group. We examined the distribution of APOE alleles in people with mental retardation having normal chromosome constitute. We studied 55 mental retardation individuals without chromosome anomaly and compared the frequency of APOE allele with 89 control samples. The APOE genotype was determined by HhaI restriction enzyme analysis of DNA amplified by polymerase chain reaction. The frequencies of APOE alleles in mental retardation patients were 3.6% (epsilon2), 88.2% (epsilon3), and 8.2% (epsilon4). The frequencies in controls were 10.1% (epsilon2), 73.6% (epsilon3), and 16.3% (epsilon4). The frequencies of APOE epsilon2 and epsilon4 alleles in mental retardation patients were significant lower than that in controls (p<0.05), but the frequency of APOE epsilon3 allele was higher reversely (p<0.01). These results suggest that APOE alleles are associated with mental retardation although the biological role of APOE in pathogenesis of mental retardation is unknown.