Aspartylglucosaminuria

Aspartylglucosaminuria (AGU) is an inherited lysosomal storage disorder that affects the brain, bones, and connective tissue. This is due to a deficiency of the enzyme aspartylglucosaminidase. Children with AGU are normal for the first few years of life. They develop progressive intellectual disability that greatly affects speech. Other symptoms include weak bones that break easily, loose joints and skin, and frequent infections. Adults with AGU may have seizures and movement problems. Individuals with AGU usually survive into mid-adulthood. There is no cure for AGU; however medical surveillance and care may help to improve some symptoms and overall condition of life. AGU is caused by pathogenic variants in the AGA gene.

AGU is inherited in an autosomal recessive manner. This type of inheritance requires the presence of two copies of a pathogenic variant in the gene for a person to have the genetic disease. Both parents must be carriers of a pathogenic variant in the gene in order to be at risk to have an affected child. The child must inherit a pathogenic variant from each carrier parent in order to be affected. There is a 1 in 4 chance that a baby will inherit two mutated copies of the gene and be affected when both parents are carriers.

There are generally no signs or symptoms associated with being a carrier for AGU. However, the risk to have a child affected with AGU is increased. Testing of reproductive partners is recommended for carriers of AGU.

AGU is a rare disorder. In Finland, it is estimated to affect 1 in 18,500 people. It is much less common outside of Finland.

Genetics Home Reference: Aspartylglucosaminuria (http://ghr.nlm.nih.gov/)
Genetic Alliance: Aspartylglucosaminuria (http://www.diseaseinfosearch.org/)

OMIM [AGU: 208400] (http://www.ncbi.nlm.nih.gov/omim)

• Full gene sequencing