Meyahealth
HomeGeneticsGeneGALNS gene
Back to Gene
GALNS gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

GALNS gene

The GALNS gene provides instructions for producing the enzyme N-acetylgalactosamine 6-sulfatase, which is essential for breaking down complex sugar molecules in lysosomes.

Normal Function

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).

Health Conditions Related to Genetic Changes

Mucopolysaccharidosis type IV

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.

Other Names for This Gene

  • chondroitinase
  • chondroitinsulfatase
  • FLJ17434
  • FLJ42844
  • FLJ98217
  • galactosamine (N-acetyl)-6-sulfate sulfatase
  • galactose-6-sulfate sulfatase
  • GALNAC6S
  • galNAc6S sulfatase
  • GALNS_HUMAN
  • GAS
  • MPS4A
  • N-acetylgalactosamine-6-sulfatase
  • N-acetylgalactosamine-6-sulfatase precursor
  • N-acetylgalactosamine-6-sulfate sulfatase

Frequently Asked Questions

Regular ophthalmologic exams every 6–12 months are recommended; if corneal clouding impairs vision, corneal transplantation may be considered, though the underlying enzyme deficiency can affect graft survival, so coordination with a metabolic specialist is essential.
MPS IV is autosomal recessive; each sibling of an affected individual has a 25 % chance of being affected, a 50 % chance of being a carrier, and a 25 % chance of being unaffected and not a carrier. Genetic counseling and carrier testing for the partner are advised before conception.
Enzyme replacement therapy (ERT) with elosulfase alfa can reduce keratan sulfate buildup and improve endurance; however, it does not reverse skeletal deformities, so orthopedic surgery and physiotherapy are often needed alongside ERT.
While no diet can replace the missing enzyme, maintaining a healthy weight, engaging in low‑impact aerobic activities, and using assistive devices to support joints can lessen stress on the spine and hips, potentially slowing the onset of severe deformities.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

Meyahealth

Ⓒ 2026. All rights reserved by MEYA

About UsTerms & PolicyFAQ