Mice with an Aspartylglucosaminuria Mutation Similar to Humans Replicate the Pathophysiology in Patients

• Published in: Human molecular genetics 1998-02, Vol.7 (2), p.265-272
• Main Authors: Jalanko, Anu, Tenhunen, Kai, McKinney, Cindy E., LaMarca, Mary E., Rapola, Juhani, Autti, Taina, Joensuu, Raimo, Manninen, Tuula, Sipilä, Ilkka, Ikonen, Sami, Riekkinen, Paavo, Ginns, Edward I., Peltonen, Leena
• Format: Article
• Language: English
• Subjects: Acetylglucosamine - analogs & derivatives; Acetylglucosamine - urine; Animals; Aspartylglucosaminuria; Aspartylglucosylaminase - genetics; Biological and medical sciences; Brain - metabolism; Brain - pathology; Carbohydrates (enzymatic deficiencies). Glycogenosis; Disease Models, Animal; Disease Progression; Errors of metabolism; Gene Targeting; Genes, Recessive; Humans; Intellectual Disability - genetics; Liver - pathology; Lysosomal Storage Diseases - enzymology; Lysosomal Storage Diseases - genetics; Magnetic Resonance Imaging; Maze Learning; Medical sciences; Metabolic diseases; Mice; Mice, Knockout - genetics; Microscopy, Electron; Phenotype
• ISSN: 0964-6906; 1460-2083; 1460-2083
• DOI: 10.1093/hmg/7.2.265

Aspartyglucosaminuria (AGU) is a lysosomal storage disease with autosomal recessive inheritance that is caused by deficient activity of aspartylglucosamini-dase (AGA), a lysosomal enzyme belonging to the newly described enzyme family of N-terminal hydro-lases. An AGU mouse model was generated by targeted disruption of the AGA gene designed to mimic closely one human disease mutation. These homo-zygous mutant mice have no detectable AGA activity and excrete aspartylglucosamine in their urine. Analogously to the human disease, the affected homo-zygous animals showed storage in lysosomes in all analyzed tissues, including the brain, liver, kidney and skin, and lysosomal storage was already detected in fetuses at 19 days gestation. Electron microscopic studies of brain tissue samples demonstrated lyso-somal storage vacuoles in the neurons and glia of the neocortical and cortical regions. Magnetic resonance images (MRI) facilitating monitoring of the brains of living animals indicated cerebral atrophy and hypo-intensity of the deep gray matter structures of brain—findings similar to those observed in human patients. AGU mice are fertile, and up to 11 months of age their movement and behavior do not differ from their age-matched littermates. However, in the Morris water maze test, a slow worsening of performance could be seen with age. The phenotype mimics well AGU in humans, the patients characteristically showing only slowly progressive mental retardation and relatively mild skeletal abnormalities.