Definition

Tuberous sclerosis complex (TSC) is an autosomal dominant disease caused by pathogenic variants in the TSC1 or TSC2 genes, which negatively regulate the mTOR pathway; ~70% of confirmed cases carry a TSC2 mutation and 20% carry a TSC1 mutation. Standard molecular tests detect a pathogenic variant in ~90% of patients with a clinically definite TSC diagnosis.

Gene/region examined

TSC1, TSC2

Method

Next-Generation Sequencing, CNV Analysis

Accepted sample types

EDTA Blood

Inheritance

Mostly germline (one third familial, the rest de novo), while somatic mosaicism plays a significant role in a substantial portion of cases that test negative on standard testing.

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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