Definition

Biallelic variants in the ADSL gene inactivate the adenylosuccinate lyase enzyme, which functions in the purine de novo synthesis pathway; abnormal metabolites such as SAICA-riboside and succinyladenosine accumulate and are diagnostic. The most severe form presents with neonatal encephalopathy and early death; Type I is characterized by severe psychomotor retardation, microcephaly and early-onset seizures, while Type II follows a more slowly progressive course with mild to moderate psychomotor retardation.

Gene/region examined

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

Method

Sequence analysis

Accepted sample types

EDTA blood, AF, CVS

Inheritance

Hereditary, autosomal recessive (AR).

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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