Neurofibromatosis type I (NF1) is a genetic disorder that affects approximately 1 in 3500 individuals. Half of people with NF1 inherit the condition from a parent, and half have a new occurrence of the condition. The manifestation of NF1 is highly variable and multiple organ systems are typically affected. Some of the more common symptoms include benign neurofibromas, café au lait spots, Lisch nodules (tan spots on the iris of the eye). Some individuals with NF1 also exhibit more severe associated conditions, such as optic pathway tumors (gliomas) or bones bending or curving. Neurocognitive deficits and specific learning disabilities occur in approximately 30 to 50% of individuals with NF1 and are regarded by some observers and sufferers to be among the most troubling features of a disease. The most commonly reported findings are deficits in visuoperceptual ability, motor coordination, expressive and receptive language, and executive functioning, which requires intact short-term memory and attention. Patients with NF1 also show a slight depression in mean IQ scores compared to healthy adults without the disorder.

While cognitive deficits are now a widely-recognized feature of Neurofibromatosis Type 1 (NF1), the precise cause of these deficits still remain to be determined. Dr. Alcino Silva, a co- investigator on this study, has developed an animal model of NF1 in which mice have a specific mutation of the *NF1* gene. These mice are physically normal but show specific learning impairments. Dr. Silva's lab found that treatment with a medication called lovastatin, a drug typically used for high cholesterol, reversed some of the spatial deficits seen in these animals. Lovastatin is a medication commonly used to treat high cholesterol and has been proven to be relatively safe and tolerable in humans.

The investigators are now conducting a randomized, double-blinded, placebo- controlled, trial of lovastatin in patients with NF1. Participants will be randomly assigned to lovastatin or placebo and treated for approximately 14 weeks with baseline and follow-up assessments to evaluate safety and any effects on neurocognitive test performance.