title: Biochemical and behavioural phenotyping of a mouse model for GAMT deficiency.
abstract: Deficiency of guanidinoacetate N-methyltransferase (GAMT) is the first described creatine (CT) deficiency syndrome in man, biochemically characterized by accumulation of guanidinoacetic acid (GAA) and depletion of CT. Patients exhibit severe developmental and muscular problems. We created a mouse model for GAMT deficiency, which exerts biochemical changes comparable with those found in human GAMT-deficient subjects. CT and creatinine (CTN) levels are significantly decreased and GAA is increased in knockout (KO) mice. In patients, other guanidino compounds (GCs) appear to be altered as well, which may also contribute to the symptomatology. Extensive evaluation of GCs levels in the GAMT mouse model was therefore considered appropriate. Concentrations of 13 GCs in plasma, 24-h urine, brain and muscle of GAMT mice were measured. We also report on the detailed behavioural characterization of this model for GAMT deficiency. Besides an increase of GAA and a decrease of CT and CTN in plasma, 24-h urine, brain and muscle of KO mice, we observed a significant increase of other GCs in brain and muscle that was sometimes reflected in plasma and/or urine. KO mice displayed mild cognitive impairment. In general, it could be concluded that the GAMT mouse model is very useful for biochemical research of GAMT deficiency, but shows only a mild cognitive deficit.
authors.affiliation: Laboratory of Neurochemistry and Behaviour/Born Bunge Foundation, University of Antwerp, Department of Biomedical Sciences, Universiteitsplein 1, 2610 Antwerp (Wilrijk), Belgium.
authors.forename: An
authors.initials: A
authors.lastname: Torremans
authors.forename: Bart
authors.initials: B
authors.lastname: Marescau
authors.forename: Ilse
authors.initials: I
authors.lastname: Possemiers
authors.forename: Debby
authors.initials: D
authors.lastname: Van Dam
authors.forename: Rudi
authors.initials: R
authors.lastname: D'Hooge
authors.forename: Dirk
authors.initials: D
authors.lastname: Isbrandt
authors.forename: Peter Paul
authors.initials: PP
authors.lastname: De Deyn
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D001923:Brain Chemistry; D003401:Creatine / Q000172:deficiency / Q000378:metabolism; D003404:Creatinine / Q000378:metabolism; D003677:Deficiency Diseases / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology*; D004195:Disease Models, Animal; D005106:Exploratory Behavior / Q000502:physiology; D005998:Glycine / Q000031:analogs & derivatives* / Q000378:metabolism; D050937:Guanidinoacetate N-Methyltransferase; D008568:Memory / Q000502:physiology; D008780:Methyltransferases / Q000172:deficiency* / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009043:Motor Activity / Q000235:genetics; D009132:Muscles / Q000378:metabolism; D009483:Neuropsychological Tests; D010641:Phenotype; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000235:genetics; D045442:Rotarod Performance Test / Q000379:methods; D013037:Spatial Behavior / Q000502:physiology
chemical_list: D003404:Creatinine; D008780:Methyltransferases; D050937:Guanidinoacetate N-Methyltransferase; C004946:glycocyamine; D003401:Creatine; D005998:Glycine