CHARACTERIZATION OF NATURALLY-OCCURRING CUTANEOUS NEUROFIBROMATOSIS IN HOLSTEIN CATTLE - A DISORDER RESEMBLING NEUROFIBROMATOSIS TYPE-1 IN HUMANS

Neurofibromatosis in cattle is typically a noncutaneous disease. A sma ll group of cows in a Holstein dairy herd developed cutaneous neurofib romatosis. This unique condition was investigated and compared with ne urofibromatosis type 1 (NF1) in humans. All cutaneous lesions but one were consistent with neurofibromas in noncutaneous sites in cattle and neurofibromas in patients with NF1. One bovine lesion was classified as a neurofibrosarcoma. Immunohistochemistry and electron microscopy s upported Schwannian differentiation in benign and malignant lesions. L inkage analysis with a polymorphism in the bovine NF1 gene confirmed t hat two affected animals from the same sire inherited the same paterna l NF1 allele. Bovine cutaneous neurofibromatosis is a naturally occurr ing disease in this group of animals, characterized by skin tumors mor phologically identical to those of NF1. An informative polymorphism at the NF1 locus of two animals and their sire suggests this disorder ma y be caused by hereditary mutations at the bovine NF1 locus.