The Neurofibromatoses. Part 1: NF1

The neurofibromatoses, including neurofibromatosis 1 (NF1), neurofibromatosis 2 (NF2), and schwannomatosis, comprise a group of genetically distinct disorders of the nervous system unified by the predisposition to nerve sheath tumors. NF1 is the most common neurogenetic disorder, with a birth incidence of 1 in 3000. NF1 is inherited in auto-somal dominant fashion with full penetrance and variable expressivity. The hallmark lesion of NF1 is the neurofibroma, a benign tumor derived from the nerve sheath and composed of a mixture of proliferating Schwann cells, fibroblasts, mast cells, and pericytes. Other findings include gliomas, learning disability, vasculopathy, and bony abnormalities. Café au lait macules are typically the initial clinical manifestation of NF1 and tend to increase in size and number throughout childhood and puberty. Current treatment of patients with NF1 remains primarily surgical. Genetic counseling is essential for adult patients because molecular diagnostic testing can minimize the risk of transmission to children.