Definition

Variants in genes involved in GPI-anchor biosynthesis, such as PIGA (X chromosome) or the autosomal gene PIGN, impair synthesis of the GPI anchor that attaches cell surface proteins to the membrane. Developmental delay, epilepsy, dysmorphic facial features, cleft lip/palate, and microcephaly may be seen; many cases are lost in early infancy.

Gene/region examined

PIGM - Exon 1

Method

Sequence analysis

Accepted sample types

EDTA blood, AF, CVS

Inheritance

Inherited, PIGA is X-linked recessive; other GPI-anchor genes (including PIGN) are inherited in an autosomal recessive manner.

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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