The functional significance of T2 hyperintense lesions (UBOs) and their role in learning disabilities associated with neurofibromatosis type 1 (NF-1) were studied by quantitative magnetic resonance spectroscopy (MRS) in 7 male patients, aged 6-19 years, and 7 controls, at Johns Hopkins University, Baltimore, MD. Choline metabolite concentrations within UBOs, globus pallidus, and thalami were elevated in younger NF-1 subjects (<10 years), and were normal in older patients. N-acetylaspartate (NAA) levels were preserved in younger subjects and reduced in older patients. NAA was also decreased in the periventricular white matter. The MRS metabolic abnormality in UBOs of NF-1 is representative of a more generalized abnormality in affected brain regions. Choline elevations, reflecting increased myelin turnover in edematous areas, is followed by axonal injury and reduced NAA. [1]
COMMENT. This work is an extension of previous reports from Johns Hopkins University concerning the relationship between UBOs and lower IQs in children with neurofibromatosis-1 [2]. (see Progress in Pediatric Neurology III, PNB Publ, 1997;pp291-294, for a review of these and other reports, some showing conflicting results).
Ped Neur Briefs Nov 1997;11:84, reviews an article on learning disability subtypes in children with neurofibromatosis; academic underachievers fall into 3 groups: 40% have normal IQ test results, 50% have general learning disabilities, and 14% have visuospatial and motor coordination problems, without language deficits.