Neurofibromatosis type I (NF1) is the most common autosomal dominant disorder in humans. It occurs with a frequency of one in 4,000 individuals. NF1 is one of the tumor predisposition syndromes affecting nervous system. It may cause benign or malignant neurofibromas. NF1 is characterized by café au lait spots, dermal neurofibromas, Lisch nodules of the iris, axillary freckling, and sphenoidal bone dysplasia. Oral manifestations include oral neurofibromas, enlarged fungiform papillae, and intrabony lesions. The gene responsible for neurofibromatosis type I is NF1 gene which encodes neurofibromin. It is expressed in neurons, astrocytes, white blood cells, and gonadal tissue. Objective: to study the gene and mutation that caused severe facial manifestation of neurofibromatosis type I in a Thai woman. Method: Clinical and histological examinations were performed. The patient was reexamined again after 14 years. Mutation analysis of NF1 gene was done. Results: Histological study supported the clinical study of neurofibromatosis type I. The novel mutation of 4821delA was found in exon 28 of NF1 gene. The mutated protein truncated at the beginning of the lipid binding SEC14-like domain, which intereacts with G-protein B and G subunits. The mutation removes this particular domain and the rest of the protein (around 1232 amino acids). Conclusion: We report the novel mutation of NF1 gene that underlies the most severe facial manifestation of neurofibromatosis type I.
This study is supported by The Thailand Research Fund (TRF)
Keywords: café au lait spots, neurofibromatosis, neurofibroma, neurofibromin, NF1