A population-based study in southeast Wales and reported from the Institute of Medical Genetics and Section of Neurology, University of Wales College of Medicine, Cardiff, has identified 135 patients with neurofibromatosis type 1 (NF-1), a prevalence of approximately 1/5000. The major clinical features were multiple cafe-au-lait spots, dermal neurofibromas, Lisch nodules in the iris (93%), freckling in the axilla (67%) or groin (44%), macrocephaly (45%), and short stature (34%). Complications included plexiform neurofibromas in 40 (30%) patients, mental retardation in 13 (10%) severe in only 1, epilepsy 6 (4%), severe scoliosis 6, visceral and endocrine tumors 6, optic glioma 2, spinal neurofibroma 2, aqueductal stenosis 2, delayed puberty 2, and congenital glaucoma 1. No cases of acoustic neuroma were seen. The frequency of CNS and malignant tumors was 5%. The authors recommend regular biannual examinations during childhood, with particular attention to intellectual development and appropriate remedial education as necessary. In families of NF-1 patients, at-risk children who have not developed cafe-au-lait spots or Lisch nodules by 5 years of age are virtually certain to have escaped inheritance of the dominant gene. 
COMMENT. This article represents a major study and addition to the literature on neurofibromatosis type 1. Items of interest to the pediatric neurologist include the association of macrocephaly, mental retardation, and epilepsy. Hypsarrythmia occurred more frequently than expected with NF-1 (2 cases) and this association has been noted previously . For correspondence, Dr. Huson's present address: Kennedy Galton Centre for Clinical Genetics, Northwick Park Hospital, Watford Road, Harrow, Middlesex HA1 3UJ, UK.