Abstract Details Title Vitamin D defiency as Neurological manifestation of Neurofibromatosis Type1 Topic General Neurology Presentation(s) P11 - Poster Session 11 (11:45 AM-12:45 PM) Poster/Presentation Number 2-002 Background Neurofibromatosis type 1 (NF1) is one of the most common autosomal dominant genetic disorders. Some clinical manifestations are present at birth, while some develop during childhood, and others can occur at any age. Given the early age at which patients develop clinical features, diagnosis is often made during childhood. The most prevalent features of NF1 are café au lait spots, dermal and plexiform neurofibromas, and learning disability. A variety of skeletal problems may be seen in NF1, including scoliosis, short stature, and pseudoarthrosis. Reduced skeletal bone mass has been documented to be a common phenomenon in children and adults with NF1. Decreased serum 25-hydroxyvitamin D (vitamin D) levels have been noted in adults and children with NF1 Objective The primary objective of this study was to evaluate vitamin D levels among children and adolescents with NF1 Design/Methods This was an observational, cross-sectional, hospital-based study. We obtained a convenience sample of individuals with confirmed diagnosis of NF1 from patients attending the Neurofibromatosis clinic over past 2 years We evaluated vitamin D levels in blood samples of patients with NF1 by a chemiluminescent immunoassay method. Correlation with neurological manifestations of weakness, numbness and tingling were made Results Of the 200 patients, 101 (50.9%) were female and 99 (49.1%) were male. Patient ages ranged from a minimum of 5 to a maximum of 72 years (mean age 56 years) and the median was 46 years. The mean value of vitamin D was 18.82 ng/mL and the median was 31 ng/mL. Conclusions The levels of vitamin D below normal of 30 ng/ml, was seen to coorelate strongly with neurological symptoms of weakness, numbness and tinling in > 50% of cases. Authors/Disclosures Hans H. Shuhaiber, MD PRESENTER Dr. Shuhaiber has nothing to disclose.