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Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®


Reviewed June 2011

What is the official name of the ALDOB gene?

The official name of this gene is “aldolase B, fructose-bisphosphate.”

ALDOB is the gene's official symbol. The ALDOB gene is also known by other names, listed below.

What is the normal function of the ALDOB gene?

The ALDOB gene provides instructions for making the aldolase B enzyme. This enzyme is one of a group of three aldolase enzymes that are responsible for breaking down certain molecules in cells throughout the body. Four identical aldolase B enzymes need to be attached (bound) to each other in a four-enzyme unit called a tetramer to work.

Aldolase B is found primarily in the liver, but it is also present at lower levels in kidney and intestinal cells. Aldolase B is involved in the breakdown (metabolism) of the simple sugar fructose, which is found mostly in fruits and is used in the body for energy. Aldolase B is responsible for the second step in the metabolism of fructose, which breaks down the molecule fructose-1-phosphate into glyceraldehyde and dihydroxyacetone phosphate. To a lesser degree, aldolase B is also involved in the breakdown of the simple sugar glucose.

How are changes in the ALDOB gene related to health conditions?

hereditary fructose intolerance - caused by mutations in the ALDOB gene

More than 50 mutations in the ALDOB gene have been found to cause hereditary fructose intolerance, a condition characterized by nausea and intestinal discomfort following ingestion of foods containing fructose. Most of these mutations replace single protein building blocks (amino acids) in the aldolase B enzyme and result in the production of an enzyme with reduced function. A mutation found in approximately half of people with hereditary fructose intolerance replaces the amino acid alanine with the amino acid proline at position 149 in the enzyme (written as Ala149Pro or A149P). This mutation alters the 3-dimensional shape of the enzyme. Alteration of the shape of the enzyme makes it difficult for the aldolase B enzymes to bind together and form tetramers. If it is not in a tetramer, aldolase B cannot metabolize fructose.

A lack of functional aldolase B results in an accumulation of fructose-1-phosphate in liver cells. This buildup is toxic, resulting in the death of liver cells over time. Additionally, the breakdown products of fructose-1-phosphase are needed in the body to produce energy and to maintain blood sugar levels. The combination of decreased cellular energy, low blood sugar, and liver cell death leads to the features of hereditary fructose intolerance.

Where is the ALDOB gene located?

Cytogenetic Location: 9q21.3-q22.2

Molecular Location on chromosome 9: base pairs 101,420,559 to 101,435,779

The ALDOB gene is located on the long (q) arm of chromosome 9 between positions 21.3 and 22.2.

The ALDOB gene is located on the long (q) arm of chromosome 9 between positions 21.3 and 22.2.

More precisely, the ALDOB gene is located from base pair 101,420,559 to base pair 101,435,779 on chromosome 9.

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

Where can I find additional information about ALDOB?

You and your healthcare professional may find the following resources about ALDOB 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 ALDOB gene or gene products?

  • ALDB
  • ALDO2
  • aldolase 2
  • aldolase B, fructose-bisphosphatase
  • fructose-bisphosphate aldolase B
  • liver-type aldolase

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

What glossary definitions help with understanding ALDOB?

acids ; alanine ; amino acid ; breakdown ; cell ; enzyme ; fructose ; gene ; glucose ; hereditary ; kidney ; metabolism ; molecule ; mutation ; phosphate ; proline ; protein ; simple sugar ; toxic

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


  • Dalby AR, Tolan DR, Littlechild JA. The structure of human liver fructose-1,6-bisphosphate aldolase. Acta Crystallogr D Biol Crystallogr. 2001 Nov;57(Pt 11):1526-33. Epub 2001 Oct 25. (
  • Esposito G, Vitagliano L, Santamaria R, Viola A, Zagari A, Salvatore F. Structural and functional analysis of aldolase B mutants related to hereditary fructose intolerance. FEBS Lett. 2002 Nov 6;531(2):152-6. (
  • Malay AD, Allen KN, Tolan DR. Structure of the thermolabile mutant aldolase B, A149P: molecular basis of hereditary fructose intolerance. J Mol Biol. 2005 Mar 18;347(1):135-44. Epub 2005 Jan 20. (
  • NCBI Gene (
  • Santer R, Rischewski J, von Weihe M, Niederhaus M, Schneppenheim S, Baerlocher K, Kohlschütter A, Muntau A, Posselt HG, Steinmann B, Schneppenheim R. The spectrum of aldolase B (ALDOB) mutations and the prevalence of hereditary fructose intolerance in Central Europe. Hum Mutat. 2005 Jun;25(6):594. (


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.

Reviewed: June 2011
Published: March 23, 2015