Brain morphology and neuropsychological functioning were examined in 52 children and adolescents with neurofibromatosis type 1 (NF-1), and findings compared with 19 controls, at the University of Texas MD Anderson Cancer Center, Houston, TX. Total brain volume and especially gray matter, by quatitative MRI, was significantly greater for NF-1 subjects than controls, and the difference was more pronounced in younger subjects. The volume of gray matter in NF-1 patients was correlated with the degree of learning disability and a greater discrepancy between academic potential (IQ) and performance (academic achievement). A significantly greater regional corpus callosum size in NF-1 subjects was associated with diminished performance in tests of academic achievement and visuo-spatial and motor skills. 
COMMENT. NF-1 can be associated with macrocephaly and learning disabilities, possibly related to a delay in developmental apoptosis and appropriate neuronal connections.
The value of the NIH criteria for diagnosis of NF-1 in early childhood was examined in 1893 patients from the International Database and reported from the University of British Columbia, Vancouver, Canada . The diagnosis is not always apparent in the first few years of life. The frequency of NF1 cases meeting the NIH Diagnostic Criteria by 1 year of age, 8 years, and 20 years, is 46%, 97%, and 100%, respectively. Cafe-au-lait macules, axillary freckling, Lisch nodules, and neurofibromas appear in that order. Patients with optic glioma are usually diagnosed by 3 years, and osseous lesions appear within the first year.