This is an autosomal recessive lysosomal storage disorder that involves the central nervous system, skeletal system and the connective tissue. (Online Mendelian Inheritance in Man number - 208400).
The disorder is caused by deficient activity of the lysosomal enzyme glycosylasparaginase.
When do we suspect AGU?
Patients with AGU have normal development in infancy. There is onset of symptoms around 2-4 years of age with
Increased respiratory tract infection
Neuroregression with decline of mental and motor skills around puberty and resultant severe intellectual disability around 25 – 28 years of age
Coarse facial features
How is AGU diagnosed?
1. Urinary excretion of aspartylglucosamine
2. Molecular analysis of AGA gene – 4 ml blood in EDTA vacutainer is required for this testing. It is also helpful to send the blood sample of the parents
for carrier testing and confirmation of the mutations identified in the affected patient.
What are the treatment options available?
Symptomatic and supportive therapy and monitoring for possible complications
How to prevent the birth of a child with AGU?
1. Parents of a child with AGU are carriers. They will never develop any disease manifestations.
2. For a couple with one child with AGU, or those who are identified to be carriers, there is a 25% risk of recurrence in each pregnancy.
3. Prenatal diagnosis by chorionic villus sampling and molecular analysis for the familial mutation is performed at 11 weeks of gestation.
4. Carrier testing by molecular analysis of siblings of the parents of an affected child should be offered. They have a 50% of being carriers.
When to contact a Medical Professional?
5. When a diagnosis of AGU is made
6. When pregnancy is planned in a family with history of AGU disease
Who to contact for more information?
7. The Department of Health Research and Indian Council of Medical Research have constituted a National Task Force to perform a multicentric collaborative
study at different research institutes across the country.