Apolipoprotein E genotypes of normal and hyperlipidemic subjects

Area of Science:

• Human genetics
• Lipid metabolism
• Cardiovascular disease

Background:

• Apolipoprotein E (apo E) regulates human lipid metabolism.
• Three major apo E isoforms (E2, E3, E4) exist, differing at amino acid positions 112 and 158.
• Apo E3 is prevalent in normal populations; E2 and E4 are linked to hyperlipoproteinemia.

Purpose of the Study:

• Determine the frequency of apo E isoform distribution in the Korean population.
• Investigate apo E isoform associations with diabetes and cardiovascular disease in Koreans.

Main Methods:

• Apolipoprotein E (apo E) genotyping was performed using polymerase chain reaction (PCR) amplification.
• Restriction isotyping utilized the Hha I restriction enzyme and polyacrylamide gel electrophoresis.
• Allele frequencies were analyzed in normal subjects, diabetic patients with hyperlipoproteinemia, and patients with cardiovascular disease and hyperlipidemia.

Main Results:

• In normal Koreans, apo E allele frequencies were E2 (4.8%), E3 (84.9%), and E4 (10.3%).
• Diabetic patients showed similar apo E allele frequencies (E2: 6.3%, E3: 81.0%, E4: 12.7%) with no significant difference from normal subjects.
• Patients with cardiovascular disease and hyperlipidemia exhibited a significantly higher apo E4 allele frequency (20.0%) compared to normal subjects (p < 0.005).

Conclusions:

• Apo E3 is the most common isoform in Koreans, with a lower frequency of apo E2 compared to Caucasians.
• The apo E4 allele is significantly associated with cardiovascular disease and hyperlipidemia in the Korean population.
• Apolipoprotein E (apo E) isoform distribution may be a determinant of hyperlipoproteinemia, and PCR is a useful genotyping method.