Alzheimer Disease, Recovery from Traumatic Brain Injury, Coronary Heart Disease
Apolipoprotein E (ApoE) function is to transport cholesterol and other lipids in blood circulation and the central nervous system. ApoE is essential to maintain the structural integrity of lipoproteins, stabilize and solubilize lipoproteins in the blood, and to serve as cofactor in enzymatic reaction.
ApoE mediates cholesterol metabolism in an isoform dependent manner. The human ApoE gene exists as three polymorphic alleles – isoforms ε2, ε3 and ε4. Differences between the three ApoE isoforms are limited to amino acid residues 112 and 158, where either cysteine or arginine is present. The single amino acid differences at these positions affect the structure of ApoE isoforms and influence their ability to bind lipids, receptors and amyloid-B peptides in brain.
Patients with the ApoE4 genotype recover from brain injury much more slowly, have an increased danger of postoperative complications in cognitive functions, and also have a much worse general prognosis. The ApoE4 genotype is also associated with an elevated risk of late onset Alzheimer’s disease and coronary heart disease.
Indications for genetic testing:
1. Risk assessment for Alzheimer disease
2. Determination of prognosis for recovery of the brain injury
3. Risk assessment for
3. Genetic counseling