Undecussated superior cerebellar peduncles and absence of the dorsal transverse pontine fibers: a new axonal guidance disorder?

Axonal guidance disorders are a newly recognized group of diseases of the human central nervous system. These disorders are characterized by white matter tracts with abnormal course and failure to cross the midline or presence of ectopic white matter tracts. Diffusion tensor imaging (DTI) and fiber tractography are suitable neuroimaging tools to detect morphological abnormalities in the course, decussation, and location of white matter tracts.