This condition causes tumors in the brain, spinal cord, and nerves. These tumors can become cancerous. There are two types, NF1 and NF2. People with NF1 often have a wide range of symptoms, including learning difficulties, bone deformities, eye problems, and skin conditions. Hearing loss and balance problems are the main symptoms of NF2. These symptoms occur when tumors press on the nerves that carry signals from the inner ears to the brain.