Definition

The SRY gene encodes a transcription factor that initiates testis development. Loss-of-function variants in the gene, particularly in the HMG-box DNA-binding region, cause testis development to fail in individuals with a 46,XY chromosome pattern, resulting in an externally female or ambiguous genital appearance and failure of virilization at puberty; this presentation is called 46,XY gonadal dysgenesis. SRY variants account for fewer than 20% of complete 46,XY gonadal dysgenesis cases; genes other than SRY can also contribute to the presentation. Rarely, translocation of SRY to the X chromosome can lead to a male phenotype in 46,XX individuals.

Gene/region examined

SRY - Full Gene

Method

Sequence analysis

Accepted sample types

EDTA blood, AF, CVS

Inheritance

Most cases are de novo mutations; in some families, the same variant can be passed to an XY child due to somatic mosaicism in a fertile father. Phenotypic expression can vary even within the same family.

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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