Motor pathway degeneration in young ataxia telangiectasia patients: A diffusion tractography study

•Corticomotor and corticospinal ataxia telangiectasia patient tracts were analyzed.•Decreases in fractional anisotropy occurred along patient tracts.•Mean diffusivity was reduced in cerebellar peduncles in patients.•Patient corticospinal streamline number and apparent fiber density were reduced.•Young ataxia telangiectasia patients show advanced white matter degeneration.

BackgroundOur understanding of the effect of ataxia–telangiectasia mutated gene mutations on brain structure and function is limited. In this study, white matter motor pathway integrity was investigated in ataxia telangiectasia patients using diffusion MRI and probabilistic tractography.MethodsDiffusion MRI were obtained from 12 patients (age range: 7–22 years, mean: 12 years) and 12 typically developing age matched participants (age range 8–23 years, mean: 13 years). White matter fiber tracking and whole tract statistical analyses were used to assess quantitative fractional anisotropy and mean diffusivity differences along the cortico-ponto-cerebellar, cerebellar-thalamo-cortical, somatosensory and lateral corticospinal tract length in patients using a linear mixed effects model. White matter tract streamline number and apparent fiber density in patient and control tracts were also assessed.ResultsReduced fractional anisotropy along all analyzed patient tracts were observed (p < 0.001). Mean diffusivity was significantly elevated in anterior tract locations but was reduced within cerebellar peduncle regions of all patient tracts (p < 0.001). Reduced tract streamline number and tract volume in the left and right corticospinal and somatosensory tracts were observed in patients (p < 0.006). In addition, reduced apparent fiber density in the left and right corticospinal and right somatosensory tracts (p < 0.006) occurred in patients.ConclusionsWhole tract analysis of the corticomotor, corticospinal and somatosensory pathways in ataxia telangiectasia showed significant white matter degeneration along the entire length of motor circuits, highlighting that ataxia–telangiectasia gene mutation impacts the cerebellum and multiple other motor circuits in young patients.