Brain Iron Alteration in Pediatric Tourette Syndrome: A Quantitative Susceptibility Mapping Study

The cortico-striato-thalamo-cortical circuits play a crucial role in the pathogenesis of Tourette syndrome (TS). While iron deficiency has been reported in adult TS, the iron content in pediatric TS remains poorly understood. This study aims to quantitatively assess whole-brain iron deposition in pediatric TS compared to typically developing (TD) children using quantitative susceptibility mapping (QSM).

In this prospective study, we recruited 50 children with a clinical diagnosis of TS and 50 age- and gender-matched TD controls. Whole-brain images were acquired using 3D T1 and multi-echo gradient-recalled echo sequences. QSM maps were generated using the STISuite toolbox. After normalizing the QSM maps to Montreal Neurological Institute space, voxel-based analysis was applied to compare between-group differences in iron content. Additionally, we evaluated the relationship between iron content and tic severity in TS children using the Pearson's correlation test.

Compared to TD children, those with TS exhibited iron deficiency in the right anterior cingulum (p_FDR < 0.001). Conversely, increased QSM values were observed in the bilateral putamen of TS children (p_FDR < 0.001). Notably, QSM values in the left putamen showed a significant negative correlation with tic severity (p = 0.044).

Our findings suggest that disturbed brain iron homeostasis in specific regions is associated with pediatric TS. These results reinforce the importance of the cortico-striato-thalamo-cortical circuits in TS pathogenesis and highlight the potential role of iron dysregulation. Furthermore, our study demonstrates that QSM could serve as a valuable auxiliary biomarker for diagnosing and potentially monitoring pediatric TS.