General Description

Mutations in the GNPTG gene cause mucolipidosis III gamma. This gene provides instructions for making a part (subunit) of an enzyme called GlcNAc-1-phosphotransferase.Mucolipidosis III gamma is a slowly progressive disorder that affects many parts of the body. Signs and symptoms of this condition typically appear around age 3.

Individuals with mucolipidosis III gamma grow slowly and have short stature. They also have stiff joints and dysostosis multiplex, which refers to multiple skeletal abnormalities seen on x-ray. Many affected individuals develop low bone mineral density (osteoporosis), which weakens the bones and makes them prone to fracture. Osteoporosis and progressive joint problems also cause pain in people with mucolipidosis III gamma, which becomes more severe over time.

People with mucolipidosis III gamma often have heart valve abnormalities and mild clouding of the clear covering of the eye (cornea). Their facial features become slightly thickened or “coarse” over time. A small percentage of people with this condition have mild intellectual disability or learning problems. Individuals with mucolipidosis III gamma generally survive into adulthood, but they may have a shortened lifespan.

Mucolipidosis III gamma is a very rare disorder, exact prevalence is unknown. It is estimated to occur in about 1 in 1000,000 to 4000,000 individuals worldwide. ISMRD knows of 9 children in Israel and 2 children in India.

  •  ML IIIC
  •  Mucolipidosis III
  •  Mucolipidosis IIIC
  •  Mucolipidosis III, variant
  •  Mucolipidosis Type III
  •  Pseudo-Hurler Polydystrophy

Mucolipidosis Gamma Authors: Annick Raas-Rothschild, MD and Ronen Spiegel MD

Children with Mucolipidosis III Gamma Authors: Sara Cathey, MD, and Sheela Nampoothiri, MD, and others

Medical and Research Information

  • Mucolipidosis review by Dr. Richard Steet. Prepared in 2016 and updated 2018 – Review here
  • GeneReviews: Gives good descriptions of genetic diseases. Information is comprehensive, and access is free to all users.
  • Genetic Home Reference: This has an excellent description of Mucolipidosis III with good reference to other information and resources.
  • • PubMed: Most recent literature
  • OMIM: Technical information about the genetics of Mucolipidosis III. OMIM is a site developed for scientists and medical specialists and contains both general and highly technical information. Access to this site is free.
  • Clinical Trials: Registry of federally and privately supported clinical trials conducted in the United States and around the world. This site gives information about each trial’s purpose, who may participate and the location.
  • GeneTests: List of Laboratories testing for Mucolipdosis

 Patient Support Groups

  • ISMRD is the international support group for this disorder
  • • Various MPS Societies around the world also support Mucolipidosis III. 

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