Poster 67

by in  Poster Session 1

A Population-Based Study of Neurofibromatosis Type I

Brian G. Mohney, MD; David O. Hodge; Bashar M. Bata, MD
Mayo Clinic
Rochester, Minnesota

 

Introduction: The purpose of this study was to describe the incidence, demographics, and clinical manifestations of neurofibromatosis (NF) type 1 among a population-based cohort of patients.

Methods: The medical records of all patients diagnosed with NF type 1 within a defined population, from January 1, 1980, through December 31, 2009, were retrospectively reviewed.

Results: Fifty patients were diagnosed with neurofibromatosis type 1 during the 30-year period, yielding an incidence of 1.2 per 100 000 individuals. Twenty-eight patients were new mutations, yielding a de novo mutation rate of 56%. The mean age at diagnosis was 11.7 years (95% CI, 0.2-47) and 26 (52%) were males. During a mean follow-up of 9.8 years (range 3 weeks to 32 years), café-au-lait macules were diagnosed in 49 individuals (98%), neurofibromas in 26 (52%), and skeletal anomalies in 14 (28%). Three (6.0%) individuals were diagnosed with glioma of the central nervous system (CI 1.2 to 9.7%) at a mean age of 13 years (range 5 to 26 years), including one patient with optic nerve glioma diagnosed at the age of 26 years. Only one patient (2%) was diagnosed with malignant nerve sheath tumor.

Discussion: The incidence of optic nerve gliomas in this cohort was much lower than prior reports.

Conclusion: Although the prevalence and de novo mutation rate of neurofibromatosis type 1 in this population-based study were similar to prior reports, the occurrence of optic nerve gliomas was much lower.

References: No references

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