Definition

Familial defective apoB-100 is a form of hypercholesterolemia caused by the R3500Q variant in the APOB gene, which disrupts the structure of the carboxyl-terminal region of the apolipoprotein B-100 protein. This change in the region that normally mediates binding to the LDL receptor leads to weak binding of LDL to the receptor, delayed clearance from the blood, hypercholesterolemia and a risk of early coronary artery disease. Clinically it cannot be distinguished from LDLR-related familial hypercholesterolemia.

Gene/region analyzed

APOB - R3500Q

Method

Sequence analysis

Accepted sample types

EDTA blood

Inheritance

Inherited in an autosomal codominant manner.

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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