ALAS2

Aminolevulinate, delta-, synthase 2 (sideroblastic/hypochromic anemia)

What is the normal function of the ALAS2 gene?

The ALAS2 gene produces an enzyme called delta-aminolevulinate synthase 1 (ALA-synthase). This is one of two genes that encode this enzyme. The ALAS2 gene makes ALA-synthase that is expressed only in cells that will become erythrocytes, or red blood cells. The other gene that makes this enzyme, ALAS1, is turned on in all other tissues in the body. ALA-synthase carries out the first step in the production of heme, the oxygen carrying part of hemoglobin, in mitochondria. Each step in heme production is controlled by a separate gene (see below).

The activity of ALA-synthase determines how much heme, and therefore how much hemoglobin, will be produced by red blood cells. The first step in the production of heme is the manufacture of delta-aminolevulinic acid, which is achieved through the action of ALA-synthase. Seven other enzymes will modify this compound before it becomes heme.

The following genes are part of the chemical pathway for making heme.

ALAD:aminolevulinate, delta-, dehydratase
ALAS1:aminolevulinate, delta-, synthase 1
ALAS2:aminolevulinate, delta-, synthase 2 (sideroblastic/hypochromic anemia)
CPOX:coproporphyrinogen oxidase (coproporphyria, harderoporphyria)
FECH:ferrochelatase (protoporphyria)
HMBS:hydroxymethylbilane synthase
PPOX:protoporphyrinogen oxidase
UROD:uroporphyrinogen decarboxylase
UROS:uroporphyrinogen III synthase (congenital erythropoietic porphyria)

What conditions are related to the ALAS2 gene?

X-linked sideroblastic anemia - caused by mutations in the ALAS2 gene: More than 25 different mutations in the ALAS2 gene have been identified in patients with X-linked sideroblastic anemia. These mutations prevent the normal production of heme and result in reduced levels of hemoglobin in the blood. Because iron is an essential part of hemoglobin molecules, low levels of hemoglobin allow excess iron to build up in developing red blood cells (called sideroblasts). The signs and symptoms of X-linked sideroblastic anemia are a result of low hemoglobin levels and a buildup of iron in the body's tissues.

Where is the ALAS2 gene located?

Xp11.21

The ALAS2 gene is located on the short (p) arm of chromosome X at position 11.21.

See How do geneticists indicate the location of a gene? in the Handbook.

Where can I find information about ALAS2?

You may also be interested in these resources, which are designed for genetics professionals and researchers.

PubMed - Recent literature
OMIM - Genetic disorder catalog
Research Resources - Tools for researchers (4 links)

What other names do people use for the ALAS2 gene or gene products?

ALAS-E
ALAS, erythroid
ANH1
ASB
Delta-ALA synthetase
Delta-aminolevulinate synthase
HEM0_HUMAN

See How are genetic conditions and genes named? in the Handbook.

Where can I find general information about genes?

The Handbook provides basic information about genetics in clear language.

These links provide additional genetics resources that may be useful.

What glossary definitions help with understanding ALAS2?

anemia ; compound ; congenital ; enzyme ; erythrocyte ; expressed ; gene ; heme ; hemoglobin ; iron ; mitochondria ; molecule ; mutation ; oxygen ; red blood cell ; sign ; symptom ; synthetase

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.

Sources for this page (2 links)

The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook.




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