Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302, and This project was designed to characterise the sources of phenotypic variability in neurofibromatosis 1 (NF1) by a combination of clinical, statistical, epidemiological, and molecular genetic methods. We have analysed associations found in clinical and genetic data from the NNFF International Database and two other databases with logistic regression and generalized estimating equations. We then extended these methods to use multivariate probit models on familial data. These are novel statistical techniques that have not been used in this way before and yielded interesting results about the sources of phenotypic variability. We were able to determine that the presence of some features of NF1 are more influenced by variability in the NF1 allele, others by the normal NF1 allele and still others by unlinked modifying genes. We have set up, and tested the screening protocol to identify the constitutional mutations of NF1 and have obtained a number of blood samples. We have results for one of our phenotypic subgroups and are completing the analysis at the present time.14. SUBJECT TERMS Neurofibromatosis Body 5
Key Research Accomplishments 26
Reportable Outcomes 27Conclusions 31
Appendices
32
INTRODUCTIONThe natural history of neurofibromatosis 1 (NF1) is incompletely understood. It exhibits extreme clinical variability and is progressive over the course of an affected individual's life. However, the rate of progression and the occurrence of serious complications vary greatly between different patients of the same age, different affected members of a single family, and even a single affected individual at different times in life. This variability and concomitant uncertainty greatly increases the burden for affected families.The purpose of this project is to characterize the sources of phenotypic variability in NF1. The studies were performed on the world's largest NF clinical databases, together including over 5000 individuals, and used a variety of statistical and genetic epidemiological methods. Our goal was to determine if a set of clinical phenotypes exists for which allelic differences at the NF1 locus appear to be important determinants of phenotype. The molecular component of this study (undertaken by Dr. D. Viskochil, University of Utah) was to develop a molecular screening process to enable us to identify the nature of the mutations within these putative phenotypes.
BODY
Data used in these studies:Most of the initial analy...