Glutaric aciduria type 1: neuroimaging features with clinical correlation

Background: Glutaric aciduria type 1 is a rare neurometabolic disease with high morbidity.

Objective: To describe the MR imaging abnormalities in glutaric aciduria type 1 and to identify any association between the clinical and imaging features.

Materials and methods: MRI scans of 29 children (mean age: 16.9 months) with confirmed diagnosis of glutaric aciduria type 1 were retrospectively reviewed. Gray matter and white matter scores were calculated based on a previously published pattern-recognition approach of assessing leukoencephalopathies. Hippocampal formation and opercular topography were assessed in relation to the known embryological basis. MRI scores were correlated with morbidity score.

Results: The most consistent MRI abnormality was widened operculum with dilatation of the subarachnoid spaces surrounding underdeveloped frontotemporal lobes. Incomplete hippocampal inversion was also seen. The globus pallidus was the most frequently involved gray matter structure (86%). In addition to the central tegmental tract, white matter abnormalities preferentially involved the central and periventricular regions. The morbidity score correlated with the gray matter abnormality score (P = 0.004). Patients with dystonia had higher gray matter and morbidity scores.

Conclusion: Morbidity is significantly correlated with abnormality of gray matter, rather than white matter, whether secondary to acute encephalopathic crisis or insidious onset disease.