• 1: Home
• 2: MPS Diseases
  • 2.1: Overview of symptoms
  • 2.2: Overview of treatment
  • 2.3: Which are the MPS Diseases
    • 2.3.1: MPS I
    • 2.3.2: MPS II
    • 2.3.3: MPS III
    • 2.3.4: MPS IVA
    • 2.3.5: MPS IVB
    • 2.3.6: MPS VI
    • 2.3.7: MPS VII
    • 2.3.8: MPS IX
    • 2.3.9: ML I
    • 2.3.10: ML II and III
    • 2.3.11: ML IV
    • 2.3.12: Fucosidosis
    • 2.3.13: Mannosidosis
    • 2.3.14: Sialic Acid Storage Disease
    • 2.3.15: MSD
    • 2.3.16: AGU
    • 2.3.17: Winchester
    • 2.3.18: Geleo Physic Dysplasia
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• 3: Fabry Disease
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• 30: Terms and Conditions

Aspartylglycosaminuria (AGU)

Aspartylglycosaminuria (AGU) is a lysosomal storage disease which was first described by Dr. Pollitt and co-workers in 1968. It has some similarities to MPS Diseases.

What causes AGU?

As we grow older cells in our bodies are constantly being renewed and used materials excreted. Proteins called enzymes are essential in this process, but sometimes the genetic instructions for producing one of the enzymes is faulty. AGU is caused by a deficiency in the enzyme aspartylglycosaminidase. Without this enzyme, used materials cannot be completely broken down and remain stored in the body, causing progressive damage to cells. Babies may show little sign of the disease, but as more and more cells become damaged, symptoms start to appear.

How common is AGU?

The disease is very rare and to date only around 150 cases have been reported worldwide. Most of these cases come from Finland.

How is AGU inherited?

We all have genes inherited from our parents which control whether we are tall, short, fair etc. Some genes we inherit are 'recessive', that is to say that we carry the gene but it does not have any effect on our development. AGU is caused by a recessive gene. If an adult carrying the abnormal gene has a partner who also is a carrier, there will be a one in four chance with every pregnancy that the child will inherit the defective gene from each parent and will suffer from the disease. There is a two in three chance that unaffected brothers and sisters of AGU sufferers will be carriers. They can be reassured however that, as the disease is so rare, the chance of having a partner who is another carrier is very slight, provided their partner is not a cousin or other close family member.

All families of affected children should seek further information from their doctor or from a genetic counsellor before planning to have more children. There is a more detailed explanation of this complex subject in a booklet available from the MPS Society on the Pattern of Inheritance in MPS diseases. Please visit our Information Resource section.

Prenatal diagnosis

If you already have a child with AGU it is possible to have tests during a subsequent pregnancy to find out whether the baby you are carrying in affected. It is important to consult your doctor early in the pregnancy if you wish tests to be arranged.

Further information

There is a detailed booklet on AGU produced by the MPS Society in collaboration with parents and doctors drawing on their experience and with reference to medical literature. The booklet includes detailed information on the presentation and clinical management of the disease and treatment options available. Please visit our Information Resource section.