EGF genetic polymorphism is associated with clinical features but not malignant phenotype in neurofibromatosis type 1 patients.

Neurofibromatosis type 1 (NF1) is characterized by a wide variation in clinical presentation and in some cases progression to malignant tumor. Epidermal growth factor (EGF) is an important mitogen for Schwann cells and is involved in the development of malignant tumors in NF1 patients. We hypothesized that EGF +61 G/A functional polymorphism, which represents constitutional all-life exposure to higher EGF expression and circulating levels, may predispose for precocious and more aggressive manifestations of disease. We found that clinical findings of intestinal polyps are significantly more frequent in patients with G homozygous genotype (P = 0.023). Those carriers of GG genotype have earlier onset of café-au-lait spots and Lisch nodules appearance (P = 0.030 and P = 0.017, respectively). Nevertheless, the EGF overexpressing genotype-GG, is not associated with higher risk for malignant progression or severity of disease. EGF polymorphism may play a role in the earlier onset of NF1 pigment cell-related manifestations and in intestinal polyps' development. Further studies in larger samples should confirm the absence of risk for having higher severity grade or malignant phenotype in NF1 patients.