Definition

De novo heterozygous truncating variants in the ASXL2 gene impair Polycomb group histone methyltransferase function, leading to a neurodevelopmental syndrome characterized by macrocephaly, developmental delay/intellectual disability, hypotonia, seizures and episodic hypoglycemia. Distinctive facial features include a glabellar nevus flammeus, widely spaced eyes and arched eyebrows.

Gene/region examined

ASXL2 - Exon 1, ASXL2 - Exon 2, ASXL2 - Exon 3, ASXL2 - Exon 4, ASXL2 - Exon 5, ASXL2 - Exon 6, ASXL2 - Exon 7, ASXL2 - Exon 8, ASXL2 - Exon 9, ASXL2 - Exon 10, ASXL2 - Exon 11, ASXL2 - Exon 12, ASXL2 - Exon 13

Method

Sequence analysis

Accepted sample types

EDTA blood, AF, CVS

Inheritance

Hereditary (usually de novo), autosomal dominant.

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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