Definition

The APOE gene encodes apolipoprotein E, which is involved in lipoprotein transport; there are three common alleles (e2, e3, e4). The E4 allele increases amyloid plaque deposition in brain tissue and raises the risk of Alzheimer disease (a 3-4 fold relative risk increase in e3/e4 and 10-15 fold in e4/e4); the e2 allele lowers Alzheimer risk but increases the risk of early cardiovascular disease.

Gene/region analyzed

APOE- e2 Allele, APOE- e3 Allele, APOE- e4 Allele

Method

Sequence analysis

Accepted sample types

EDTA blood, AF, CVS

Inheritance

Hereditary, complex/polygenic risk factor; does not follow a Mendelian inheritance pattern.

Related Tests

Inheritance Patterns

Describes how a genetic condition is passed on within a family. There are five main patterns

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Carrier (Heterozygous / Homozygous)

Why it matters: In autosomal recessive inheritance, when each parent is a carrier (while both appear healthy), the chance of their child being born with the disease is 25% in each

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VUS (Variant of Uncertain Significance)

This is the situation where the test has detected a change in the DNA, but the role of this change in the development of disease is unconfirmed.

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How to Read a Genetic Test Result (Positive / Negative / VUS)

A genetic test result falls into three main categories

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Types of Genetic Tests

A genetic test is a type of medical test that detects changes in genes, chromosomes or proteins. Today there are more than 77,000 genetic tests available.

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