Definition

The PRNP gene encodes the normal prion protein (PrP). Mutations in this gene, or conversion of PrP into a misfolded abnormal form (PrPSc), lead to sponge-like degeneration of the brain. The genetic (familial) form presents with rapidly progressive dementia, myoclonus and behavioral changes and is usually fatal within months; acquired and sporadic forms also exist and these are not inherited.

Gene/region analyzed

PRNP - Exon 2

Method

Sequence analysis

Accepted sample types

EDTA blood, AF, CVS

Inheritance

Hereditary, autosomal dominant (in genetic forms); sporadic/acquired forms are not inherited.

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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