Possible Implication of RNF135 in High Type 1 Neurofibromatosis Tumoral Risk

Background: Recurrent type 1 and 2 microdeletions of NF1 (neurofibromatosis, type 1) gene leads to a more severe phenotype than heterozygous point mutations. The associated deletion of RNF135 (Ring Finger protein 135), a flanking NF1 gene, is known to be responsible for the childhood overgrowth syndrome but its implication in tumoral severity has never been proven.Methods and Results: A Single Nucleotide Polymorphisms array (715K) was performed in a patient with a very severe form of type 1 neurofibromatosis, as revealed by massive cervico-mediastinal plexiform neurofibromas. It showed a small 126kb atypical deletion encompassing only RNF135 and the first exon of NF1.Conclusion: This observation highlights the possible role of RNF135 in tumoral severity in type 1 neurofibromatosis caused by recurrent type 1 and type 2 microdeletions.