Brain injury in glutaric aciduria type I: the value of functional techniques in magnetic resonance imaging.
BACKGROUND
Acute striatal necrosis is a devastating consequence of encephalopathic crisis in patients with glutaric aciduria type I (GA-I), but the mechanisms underlying brain injury are not completely understood.


OBJECTIVE
To approach pathophysiological aspects of brain injury in GA-I by means of functional techniques in magnetic resonance imaging (MRI).


METHODS
Four patients during an acute encephalopathic crisis and three asymptomatic siblings with GA-I underwent single-voxel hydrogen magnetic resonance spectroscopy (MRS) and brain MRI including gradient echo T1-weighted, FLAIR, T2-weighted and diffusion-weighted imaging.


RESULTS
The study was performed between three and eight days after the onset of acute encephalopathic crisis. Isotropic diffusion images showed high signal changes with corresponding low apparent diffusion coefficient values within the putamen, caudate nuclei and globus pallidus (four patients), and the cerebral peduncles including the substantia nigra (one patient). The study disclosed normal findings in asymptomatic siblings. MRS showed decreased N-acetyl-aspartate/creatine ratio at the basal ganglia in encephalopathic patients when compared to a group of sex- and age-matched controls.


CONCLUSIONS
Brain injury in GA-I is characterized by the presence of cytotoxic edema and reduced neuronal integrity by functional imaging techniques. Involvement of the basal ganglia may be asymmetrical in patients with unilateral motor disorder and may extent to the cerebral peduncles and substantia nigra, which may be responsible for the acute onset dystonia in some patients. Functional techniques failed to demonstrate any abnormalities in asymptomatic patients, which is in agreement with the integrity of basal ganglia structures observed by conventional MRI sequences.
Pérez-Dueñas
Belén
B
Department of Neurology and Center for Biomedical Research on Rare Diseases (CIBERER), ISCIII, Hospital Sant Joan de Déu, Barcelona, Spain. bperez@hsjdbcn.org
De La Osa
Alberto
A
Capdevila
Antoni
A
Navarro-Sastre
Aleix
A
Leist
Andy
A
Ribes
Antonia
A
García-Cazorla
Angels
A
Serrano
Mercedes
M
Pineda
Mercedes
M
Campistol
Jaume
J
D000592:Amino Acid Metabolism, Inborn Errors / Q000150:complications* / Q000175:diagnosis* / Q000652:urine; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D001921:Brain / Q000473:pathology; D001930:Brain Injuries / Q000175:diagnosis* / Q000209:etiology* / Q000652:urine; D001931:Brain Mapping; D003401:Creatine / Q000378:metabolism; D005977:Glutarates / Q000378:metabolism / Q000652:urine; D050770:Glutaryl-CoA Dehydrogenase / Q000172:deficiency* / Q000235:genetics; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging / Q000379:methods; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D012189:Retrospective Studies
C108959:3-hydroxyglutaric acid; D005977:Glutarates; D001224:Aspartic Acid; C000179:N-acetylaspartate; D050770:Glutaryl-CoA Dehydrogenase; C035736:glutaric acid; D003401:Creatine