In humans, glycogen storage was repeatedly reported in nervous system of infant patients. Similarly to animal models, accumulations are located in the gray matter (neurons of the anterior horns of the spinal cord and brainstem and cortical neurons of the brain and cerebellum) (6, 8-10) as well as in oligodendrocytes with delay in myelination as early as the second trimester of gestation (11-13). Neuronal loss with areas of gliosis both in brain and spinal cord Inhibitors,research,lifescience,medical was also described (10). In the peripheral nerves, Schwann cells with glycogen-filled projections which may interfere with the correct formation of myelin was observed

(13). From a clinical point of view, a variable degree of cognitive development was reported in infant patients

(14). During Inhibitors,research,lifescience,medical the first 4 years of life, cognitive developmental scores in 10 children ranged from above-average development to developmental delay with mild mental retardation and brain imaging revealed periventricular white matter abnormalities Inhibitors,research,lifescience,medical in 4 of them (14). Differently from the infantile form of the disease, nervous system involvement in late-onset GSD II patients was poorly studied. The autopsy findings in a clinically and biochemically documented case of adult-onset disease showed no significant morphological abnormalities in the nervous system (15). Recently, brain buy ABT-263 structure and function in adult GSD II subjects were evaluated by Voxel-based morphometry (VBM), an MR technique to assess structural gray matter Inhibitors,research,lifescience,medical modifications, and by resting state functional MRI (fMRI), which is a method able to provide measures of functional brain connectivity (evaluation of interrelations between different brain regions that are part of common networks subserving complex brain functions) (11). Neuroimaging Inhibitors,research,lifescience,medical and neuropsychological findings showed significant changes in brain connectivity of the explored functional brain networks. Particularly, the Wisconsin card sorting test, which is able to detect dysfunctions of the frontal lobe,

showed impaired performance in set shifting abilities, cognitive flexibility and problem solving. Functional neuroimaging showed a selective disruption of the Salience Network, implicated in executive functioning, planning and abstract reasoning, which is consistent with the no findings of the neuropsychological profile. Differently, VBM analysis did not reveal any significant regional brain atrophy in line with autopsy studies that did not report any evidence of cortical atrophy (11, 15), thus suggesting functional disruption of neuronal networks without macroscopic structural changes in GSD II adult brains. Blood vessel involvement Brain vascular abnormalities were reported in lateonset GSD II.