Definition

The ALAS2 gene encodes 5-aminolevulinate synthase, the enzyme that catalyzes the rate-limiting first step of heme synthesis in erythroid cells. Most pathogenic variants impair enzyme activity, preventing normal heme production in erythroblasts and causing microcytic hypochromic anemia along with ring sideroblasts in the bone marrow.

Gene/region examined

ALAS2 - Exon 2, ALAS2 - Exon 3, ALAS2 - Exon 4, ALAS2 - Exon 5, ALAS2 - Exon 6, ALAS2 - Exon 7, ALAS2 - Exon 8, ALAS2 - Exon 9, ALAS2 - Exon 10, ALAS2 - Exon 11

Method

Sequence analysis

Accepted sample types

EDTA blood, AF, CVS

Inheritance

Hereditary, X-linked.

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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