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


Reviewed May 2014

What is the official name of the MAN2B1 gene?

The official name of this gene is “mannosidase, alpha, class 2B, member 1.”

MAN2B1 is the gene's official symbol. The MAN2B1 gene is also known by other names, listed below.

What is the normal function of the MAN2B1 gene?

The MAN2B1 gene provides instructions for making the enzyme alpha-mannosidase. This enzyme works in the lysosomes, which are compartments that digest and recycle materials in the cell. Within lysosomes, the enzyme helps break down complexes of sugar molecules (oligosaccharides) attached to certain proteins (glycoproteins). In particular, alpha-mannosidase helps break down oligosaccharides containing a sugar molecule called mannose.

How are changes in the MAN2B1 gene related to health conditions?

alpha-mannosidosis - caused by mutations in the MAN2B1 gene

More than 120 mutations in the MAN2B1 gene have been identified in people with alpha-mannosidosis, a rare inherited disorder that causes problems in many organs and tissues of the body. Affected individuals may have intellectual disability, distinctive facial features, and skeletal abnormalities. Some of the MAN2B1 gene mutations that cause alpha-mannosidosis change one protein building block (amino acid) in the alpha-mannosidase enzyme. Other mutations result in an abnormally shortened enzyme, or cause the enzyme to be pieced together incorrectly.

These mutations interfere with the ability of the alpha-mannosidase enzyme to perform its role in breaking down mannose-containing oligosaccharides. These oligosaccharides accumulate in the lysosomes and cause the cells to malfunction and eventually die. Tissues and organs are damaged by the abnormal accumulation of oligosaccharides and the resulting cell death, leading to the characteristic features of alpha-mannosidosis.

Where is the MAN2B1 gene located?

Cytogenetic Location: 19p13.2

Molecular Location on chromosome 19: base pairs 12,646,508 to 12,666,777

(Homo sapiens Annotation Release 107, GRCh38.p2) (NCBI (

The MAN2B1 gene is located on the short (p) arm of chromosome 19 at position 13.2.

The MAN2B1 gene is located on the short (p) arm of chromosome 19 at position 13.2.

More precisely, the MAN2B1 gene is located from base pair 12,646,508 to base pair 12,666,777 on chromosome 19.

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

Where can I find additional information about MAN2B1?

You and your healthcare professional may find the following resources about MAN2B1 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 MAN2B1 gene or gene products?

  • lysosomal acid alpha-mannosidase
  • MANB
  • mannosidase, alpha B, lysosomal

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

What glossary definitions help with understanding MAN2B1?

amino acid ; cell ; class ; disability ; enzyme ; gene ; glycoproteins ; inherited ; mannose ; molecule ; oligosaccharides ; protein

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


  • Essentials of Glycobiology (second edition, 2009): Glycoprotein Degradation (
  • Hansen G, Berg T, Riise Stensland HM, Heikinheimo P, Klenow H, Evjen G, Nilssen Ø, Tollersrud OK. Intracellular transport of human lysosomal alpha-mannosidase and alpha-mannosidosis-related mutants. Biochem J. 2004 Jul 15;381(Pt 2):537-46. (
  • Kuokkanen E, Riise Stensland HM, Smith W, Kjeldsen Buvang E, Van Nguyen L, Nilssen Ø, Heikinheimo P. Molecular and cellular characterization of novel {alpha}-mannosidosis mutations. Hum Mol Genet. 2011 Jul 1;20(13):2651-61. doi: 10.1093/hmg/ddr167. Epub 2011 Apr 19. (
  • Malm D, Nilssen Ø. Alpha-mannosidosis. Orphanet J Rare Dis. 2008 Jul 23;3:21. doi: 10.1186/1750-1172-3-21. Review. (
  • NCBI Gene (
  • Pittis MG, Montalvo AL, Heikinheimo P, Sbaragli M, Balducci C, Persichetti E, Van Maldergem L, Filocamo M, Bembi B, Beccari T. Funtional characterization of four novel MAN2B1 mutations causing juvenile onset alpha-mannosidosis. Clin Chim Acta. 2007 Jan;375(1-2):136-9. Epub 2006 Jul 6. (
  • Sbaragli M, Bibi L, Pittis MG, Balducci C, Heikinheimo P, Ricci R, Antuzzi D, Parini R, Spaccini L, Bembi B, Beccari T. Identification and characterization of five novel MAN2B1 mutations in Italian patients with alpha-mannosidosis. Hum Mutat. 2005 Mar;25(3):320. (
  • Sun H, Wolfe JH. Recent progress in lysosomal alpha-mannosidase and its deficiency. Exp Mol Med. 2001 Mar 31;33(1):1-7. Review. (


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: May 2014
Published: February 1, 2016