RESUMO
BACKGROUND: Neurofibromatosis 1 is a systemic pathology that predominantly affects the central and peripheral nervous system and the skin, although it can potentially affect any organ of the human body. The NF1 gene (Neurofibromatosis 1) is located on chromosome 17q11.2, a gene of great length that encodes neurofibromin, a protein with a tumor suppressor function with a functional mechanism that is not clearly known. METHODS: We reviewed the medical records, radiologic images, genetic studies, and clinical photographs of a patient with confirmed diagnosis of Neurofibromatosis 1 who was attended in our center between 2012 and 2021. The clinical course, the applied therapeutics and genetic findings were assessed. RESULTS: We present the case of a 10-year-old patient with a clinical diagnosis of neurofibromatosis type 1 (more than 6 coffee-with-milk spots, axillary ephelides, a cutaneous xanthogranuloma and hyperhidrosis) in whom a c.6255delG mutation (pMet2085IlefsTer2) in exon 42 of the NF1 gene was detected. There was no family history of diagnosed NF1. Neuroimaging studies showed myelin vacuolization in the posterior fossa, in dentate nucleus, midbrain and both globus pallidus. These findings showed stability over time. The patient is now asymptomatic and under evolutionary follow-up. CONCLUSIONS: The mutation shown here has not been previously described. Reports of previously unknown mutations are an important source of knowledge that can contribute to improved genetic diagnosis and a better understanding of the pathophysiological and genetic characteristics of diseases.