Author response: Teaching NeuroImages: A rare case of Jacobsen syndrome with global diffuse hypomyelination of brain.

We thank Drs. Wolfe and Van der Knaap for their insightful comment, on our Teaching NeuroImages study,1 and clarification of their precise definition of hypomyelinating disorders. We agree that HEPACAM loss of function may account for some of the issue in imaging in Jacobsen syndrome, but it does not appear to be the entire explanation, given the lack of macrocephaly or cysts in most patients reported. Regarding the hypomyelination classification, this was derived from the original radiology report, interpreted by the neuroradiologist, as a global diffuse hypomyelination with mild diffuse brain atrophy. Further longitudinal studies would certainly be of interest.