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Reviewed July 2009
What is the official name of the ALAD gene?
The official name of this gene is “aminolevulinate dehydratase.”
ALAD is the gene's official symbol. The ALAD gene is also known by other names, listed below.
Read more about gene names and symbols on the About page.
What is the normal function of the ALAD gene?
The ALAD gene provides instructions for making an enzyme known as delta-aminolevulinate dehydratase. This enzyme is involved in the production of a molecule called heme. Heme is vital for all of the body's organs, although it is found mostly in the blood, bone marrow, and liver. Heme is an essential component of several iron-containing proteins called hemoproteins, including hemoglobin (the protein that carries oxygen in the blood).
The production of heme is a multi-step process that requires eight different enzymes. Delta-aminolevulinate dehydratase is responsible for the second step in this process, which combines two molecules of delta-aminolevulinic acid (the product of the first step) to form a compound called porphobilinogen. In subsequent steps, four molecules of porphobilinogen are combined and then modified to produce heme.
How are changes in the ALAD gene related to health conditions?
Where is the ALAD gene located?
Cytogenetic Location: 9q33.1
Molecular Location on chromosome 9: base pairs 113,386,312 to 113,401,338
(Homo sapiens Annotation Release 107, GRCh38.p2) (
The ALAD gene is located on the long (q) arm of chromosome 9 at position 33.1.
More precisely, the ALAD gene is located from base pair 113,386,312 to base pair 113,401,338 on chromosome 9.
See How do geneticists indicate the location of a gene? in the Handbook.
Where can I find additional information about ALAD?
You and your healthcare professional may find the following resources about ALAD helpful.
You may also be interested in these resources, which are designed for genetics professionals and researchers.
What other names do people use for the ALAD gene or gene products?
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 ALAD?
You may find definitions for these and many other terms in the Genetics Home Reference Glossary.
See also Understanding Medical Terminology.
References (11 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.