MINOR DISEASE FEATURES IN NEUROFIBROMATOSIS TYPE-1 (NF1) AND THEIR POSSIBLE VALUE IN DIAGNOSIS OF NF1 IN CHILDREN LESS-THAN-OR-EQUAL-TO-6 YEARS AND CLINICALLY SUSPECTED OF HAVING NF1

Objective - To establish the frequency of minor disease features in ch ildren with neurofibromatosis type 1 (NF1) and to evaluate the value o f minor disease features in children less than or equal to 6 years wit h a suspected diagnosis of NF1, considering that the disease is virtua lly 100% penetrant at 6 years of age. Design - During this 10 year, pr ospective, multidisciplinary, follow up study, 209 children suspected of having NF1 were examined; 150 were diagnosed with NF1 and 59 were n ot. The present analysis included children in whom NF1 was considered to be present at 6 years of age (n = 85) and children without NF1 at 6 years of age (n = 42). Results - The minor disease features macroceph aly (52.9%), short stature (24.7%), hypertelorism (63.5%), and thorax abnormalities (37.6%) were highly prevalent in children with NF1 and s ignificantly associated with a diagnosis of NF1 at 6 years of age. In addition, the mean number of minor disease features was significantly higher in children with NF1 at 6 years of age compared to the group wi thout a diagnosis at 6 years of age (mean 1.8 v 0.8, p < 0.001). Moreo ver, children with three or more minor disease features were all diagn osed with NF1 under the age of 6 years. Multivariate analysis using a logistic regression model showed that macrocephaly, short stature, hyp ertelorism, and thorax abnormalities were all independently associated with the presence of NF1 at 6 years of age. Conclusion - In children with insufficient diagnostic criteria aged less than or equal to 6 yea rs, documentation of minor disease features may be a helpful aid in pr edicting the diagnosis of NF1 in years to come.