Alterations in Brain Morphology by MRI in Adults with Neurofibromatosis 1

Objective: To characterize alterations in brain morphology by MRI in adults with neurofibromatosis 1 (NF1). Methods: Planar (2D) MRI measurements of 29 intracranial structures were compared in 389 adults with NF1 and 112 age- and sex-matched unaffected control subjects. The 2D measurements were correlated to volumetric (3D) brain measurements for 99 of the adults with NF1. A subset of adults with NF1 (n = 70) was also assessed for clinical severity of NF1 features and neurological problems and received psychometric testing for attention deficits and IQ. Correlation analyses were performed between principal components of the intracranial measurements and clinical and psychometric features of these patients. Results: Four of nine corpus callosum measurements were significantly greater in adults with NF1 than in sex- and age-matched controls. All seven brainstem measurements were significantly greater in adults with NF1 than in controls. Increased corpus callosum and brainstem 2D morphology were correlated with increased total white matter volume among the NF1 patients. No robust correlations were observed between the 2D size of these structures and clinical or neuropsychometric assessments. Interpretation: Our findings are consistent with the hypothesis that dysregulation of brain myelin production is an important manifestation of NF1 in adults.