Definition

The azoospermia factor (AZF) region (subregions AZFa, AZFb, AZFc) on the long arm of the Y chromosome (Yq11) harbors genes required for sperm production. Microdeletions in these regions remove several genes, preventing production of proteins necessary for normal development of sperm cells; clinically, this presents as azoospermia, oligospermia, or abnormally shaped/immotile sperm, with no other symptoms. The condition occurs in approximately 1:2,000 to 1:3,000 men across all ethnic groups.

Gene/region examined

SRY - 20 STR region

Method

Gel electrophoresis

Accepted sample types

EDTA blood

Inheritance

Shows Y-linked inheritance; deletions usually arise as new events during the father's sperm formation and are not inherited. If an affected man has children naturally or through assisted reproduction (ICSI), he will pass the deletion to all his sons; daughters are not affected.

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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