« Back to Conditions List


What is Aspartylglycosaminuria?

Aspartylglycosaminuria (AGU) is an inherited condition in which an enzyme deficiency leads to variety of physical symptoms. It is most common among people of Finnish descent.

Symptoms typically appear within the first few years of life. Infants with AGU experience frequent diarrhea and infections. Other early signs include clumsiness, delayed speech, and hyperactivity.

People with the disease experience progressive mental disability, seizures, and behavioral problems. Between the ages of 13 and 16, they typically have the mental and motor development of a 5 or 6 year-old. By the mid-20s, they are severely mentally disabled.

People with AGU share certain physical features including sagging cheeks, eye deformities, a broad nose and face, a short neck, an asymmetrical head, and spinal deformities. Their facial features tend to coarsen over time, and connective tissue problems or osteoporosis may develop.

How common is Aspartylglycosaminuria?

Aspartylglycosaminuria is most common in Finland, where an estimated 1 in 26,000 babies are affected. In some regions of Finland, where carrier rates can be 1 in 40, as many as 1 in 3,600 babies will have the disease. AGU is the third most common cause of mental disability in Finland. Some studies have indicated that when the disease occurs in non-Finnish people, often the parents are close blood relatives.

How is Aspartylglycosaminuria treated?

There is no treatment for the cause of AGU. Medical professionals can only treat symptoms as they arise. These treatments may include, but are not limited to, special education, anti-seizure medication, and orthopedic aids to help in movement.

What is the prognosis for a person with Aspartylglycosaminuria?

The lifespan of a person with AGU has not been well-documented, perhaps due to the disease‚Äôs rarity. In one Canadian family, three affected siblings died in their 30s and 40s. All people with the disease experience severe mental disability and impaired motor function.


Genetics Home Reference

Explanations of an extensive number of genetic diseases written for everyday people by the U.S. government's National Institutes of Health.

The Arc

A national organization to support and connect people with intellectual and developmental disabilities. It has more than 140,000 members and 850 state and local chapters.

1010 Wayne Ave, Suite 650
Silver Spring, MD 20910
Phone: (301) 565-3842
Secondary Phone: (800) 433-5255

The International Advocate For Glycoprotein Storage Diseases

A group which supports and informs families of children affected by glycoprotein storage diseases, including aspartylglucosaminuria.

P.O. Box 328
Dexter, MI 48130
Phone: 734-449-8222

Other names for Aspartylglycosaminuria

  • Glycosylasparaginase Deficiency
  • AGU
  • Glycoasparaginase
  • Aspartylglucosaminidase Deficiency
  • AGA Deficiency
  • Aspartylglycosaminuria