Galactosamine-6-Sulfate Sulfatase

Alternative Names

  • N-Acetylgalactosamine-Sulfate Sulfatase
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OMIM Number




Uniprot ID



43,237 bases

No. of Exons


No. of isoforms


Protein Name


Molecular Mass

58026 Da

Amino Acid Count


Genomic Location


Gene Map Locus


The GALNS gene codes for an enzyme called N-acetylgalactosamine 6-sulfatase that is located within lysosomes.  This enzyme is involved in the degradation of the glycosaminoglycans (GAGs) or mucopolysaccharides, keratan sulfate, and chondroitin 6-sulfate.

Defects in this enzyme are the cause of Morquio A syndrome, a lysosomal storage disorder characterized by growth retardation; a prominent lower face, kyphoscoliosis, an abnormally short neck, knock knees, flat feet, epiphyses, pectus carinatum.  Hearing loss, weakness of the legs, abnormal heart development, abnormal skeletal development and/or additional abnormalities may also occur.

Epidemiology in the Arab World

View Map
Variant NameCountryGenomic LocationClinvar Clinical SignificanceCTGA Clinical Significance Condition(s)HGVS ExpressionsdbSNPClinvar
NM_000512.4:c.898+1G>ALebanonchr16:88835212PathogenicPathogenicMucopolysaccharidosis Type IVANG_008667.1:g.26755G>A; NM_000512.4:c.898+1G>A761850746528323
NM_000512.5:c.319G>AUnited Arab EmiratesNC_000016.10:g.88841897C>TLikely PathogenicPathogenicMucopolysaccharidosis Type IVANG_008667.1:g.20070G>A; NM_000512.5:c.319G>A; NP_000503.1:p.Ala107Thr7631846571048185
NM_000512.5:c.346G>ASaudi ArabiaNC_000016.10:g.88841068C>TPathogenicPathogenicMucopolysaccharidosis Type IVANG_008667.1:g.20899G>A; NM_000512.5:c.346G>A; NP_000503.1:p.Gly116Ser1444754604928751

Other Reports

Saudi Arabia

Qubbaj et al. (2008) performed preimplantation genetic diagnosis (PGD) for a couple with three children affected with Morquio disease, having homozygous W159C mutation in GALNS gene.  The couple were first cousins, and had a 14-year-old affected daughter and affected twin sisters. Both twins presented with dysmorphic features, spondyloepiphyseal abnormalities, short stature, and cardiac valvular involvement.  One of the twins died at the age of 4-years due to a chest infection.  The couple decided to go in for IVF and PGD for a subsequent pregnancy.  Performing ovarian stimulation, oocyte retrieval, intracytoplasmic sperm injection procedure, embryo biopsy, cell lysis, and multiple displacement amplification, three embryos out of seven were genotypically normal and two were transferred back to the mother on day 4.  Pregnancy ensued and a carrier healthy male infant was delivered.  Genetic haplotyping analysis of the infant and the leftover MDA samples showed that embryo 3 was the one that was implanted.  The misdiagnosis was explained by allele dropout (ADO) of the mutant allele in embryo 3.

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