General Description

Aspartylglucosaminuria (AGU) is caused by deficiency of the enzyme N-aspartyl-beta-glucosaminidase.

This enzyme normally degrades long sugar chains known as oligosaccharides in the lysosome. When N-aspartyl-beta-glucosaminidase is deficient, as it is in AGU, these long sugar chains build up and eventually lead to the clinical features of AGU.

Infants with aspartylglucosaminuria appear healthy at birth, and development is typically normal throughout early childhood. The first signs of this condition become evident around the age of 2 or 3, with delayed speech. Mild intellectual disability then becomes apparent, and learning occurs at a slowed pace. Intellectual disability progressively worsens in adolescence. Most people with this disorder lose much of the speech they have learned, and affected adults usually have only a few words in their vocabulary. Adults with aspartylglucosaminuria may develop seizures or problems with movement.

The Hide and Seek Foundation  and ISMRD have a summary of this disorder.

Medical and research information

  • Genetics Home Reference: This has an excellent description of aspartylglucosaminuria and has many references to other information and resources.
  • GeneTests: List of laboratories offering tests for AGU.
  • Orphanet is a database dedicated to information on rare diseases and orphan drugs. Access is free of charge.
  • OMIM: This link has technical information about the genetics of this disorder. It is a site developed for scientists and medical specialists and contains both general and highly technical information. Access to the site is free to all users.

Patient support groups