Tumors may cause increased intracranial pressure, seizure, ataxia or cranial nerve abnormalities. Schwannomas are uncommon in patients with NF-1, but can present on spinal nerve sheaths. However, in NF-2, they are the most common tumor, involving cranial and peripheral nerves. Many individuals with neurofibromatosis have below average intelligence. Types of learning disabilities may include neuromotor dysfunction and attention deficit hyperactivity disorder, as well as deficits in visuospatial processing.
Endocrinological problems associated with neurofibromatosis are common.
Short stature and growth hormone deficiency are more common in these patients than in the general population, although the exact incidence is not known. As mentioned, pheochromocytoma can occur. Increased concentrations of nerve growth stimulating activity have been linked with the development of neurofibromatosis. NF-1 is a disorder with variable phenotypic expression. Some patients may have primarily cutaneous expression, while others may have life-threatening or severely disfiguring complications.