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


Reviewed July 2010

What is the official name of the GALNS gene?

The official name of this gene is “galactosamine (N-acetyl)-6-sulfatase.”

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

What is the normal function of the GALNS gene?

The GALNS gene provides instructions for producing an enzyme called N-acetylgalactosamine 6-sulfatase. This enzyme is located in lysosomes, which are compartments within cells that break down and recycle different types of molecules. N-acetylgalactosamine 6-sulfatase is involved in the breakdown of large sugar molecules called glycosaminoglycans (GAGs) or mucopolysaccharides. Specifically, this enzyme removes a chemical group known as a sulfate from a GAG called keratan sulfate. Keratan sulfate is particularly abundant in cartilage and the clear covering of the eye (cornea).

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

mucopolysaccharidosis type IV - caused by mutations in the GALNS gene

More than 148 mutations in the GALNS gene have been found to cause mucopolysaccharidosis type IV (MPS IV). Most of these mutations change single DNA building blocks (nucleotides) in the gene. All of the mutations that cause MPS IV reduce or eliminate the function of N-acetylgalactosamine 6-sulfatase.

The lack of N-acetylgalactosamine 6-sulfatase activity leads to the accumulation of keratan sulfate within lysosomes. Because keratan sulfate is predominantly found in cartilage and the cornea, the buildup of this substance causes skeletal abnormalities and cloudy corneas. Researchers believe that a buildup of GAGs may also cause the features of MPS IV by interfering with the functions of other proteins inside lysosomes and disrupting the movement of molecules inside the cell.

Where is the GALNS gene located?

Cytogenetic Location: 16q24.3

Molecular Location on chromosome 16: base pairs 88,813,734 to 88,856,966

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

The GALNS gene is located on the long (q) arm of chromosome 16 at position 24.3.

The GALNS gene is located on the long (q) arm of chromosome 16 at position 24.3.

More precisely, the GALNS gene is located from base pair 88,813,734 to base pair 88,856,966 on chromosome 16.

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

Where can I find additional information about GALNS?

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

  • chondroitinase
  • chondroitinsulfatase
  • FLJ17434
  • FLJ42844
  • FLJ98217
  • galactosamine (N-acetyl)-6-sulfate sulfatase
  • galactose-6-sulfate sulfatase
  • galNAc6S sulfatase
  • GAS
  • MPS4A
  • N-acetylgalactosamine-6-sulfatase
  • N-acetylgalactosamine-6-sulfatase precursor
  • N-acetylgalactosamine-6-sulfate sulfatase

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

What glossary definitions help with understanding GALNS?

breakdown ; cartilage ; cell ; cornea ; DNA ; enzyme ; galactose ; gene ; precursor ; sulfate

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


  • Montaño AM, Sukegawa K, Kato Z, Carrozzo R, Di Natale P, Christensen E, Orii KO, Orii T, Kondo N, Tomatsu S. Effect of 'attenuated' mutations in mucopolysaccharidosis IVA on molecular phenotypes of N-acetylgalactosamine-6-sulfate sulfatase. J Inherit Metab Dis. 2007 Oct;30(5):758-67. Epub 2007 Sep 17. (
  • NCBI Gene (
  • Tomatsu S, Montaño AM, Lopez P, Trandafirescu G, Gutierrez MA, Oikawa H, Nishioka T, Vieira MB, Orii T, Noguchi A. Determinant factors of spectrum of missense variants in mucopolysaccharidosis IVA gene. Mol Genet Metab. 2006 Sep-Oct;89(1-2):139-49. Epub 2006 Jul 11. (
  • Tomatsu S, Montaño AM, Nishioka T, Gutierrez MA, Peña OM, Tranda Firescu GG, Lopez P, Yamaguchi S, Noguchi A, Orii T. Mutation and polymorphism spectrum of the GALNS gene in mucopolysaccharidosis IVA (Morquio A). Hum Mutat. 2005 Dec;26(6):500-12. (


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: July 2010
Published: February 8, 2016