Detection of Novel NF1 Variants with Next-Generation DNA Sequencing Technology and Genotype-Phenotype Characteristics of Neurofibromatosis

Objective: Neurofibromatosis type 1 (NF1, #162200) is a common neurological disorder with de novo or inherited germline mutations of the Neurofibromin (NF1, *613113). The purpose of this study is to increase the limited knowledge of NF1 in a small population-based dataset. Materials and Methods: This study enrolled patients with clinically suspected NF1 referred to the Kayseri Training and Research Hospital, Medical Genetics Department, between 2015 and 2017. The local ethics committee approved this study. Next-generation sequencing was performed for the genetic analysis. The genetic, demographic, and clinical features of the participants were characterized. Results: A total of 79 cases of NF1 were included. Of these cases, 40 were male, and 39 were female. The mean age was 11.9 years, and most were younger than 18 years. The most common complaint was cafe au lait macules. The 61 (77.3%) patients had pathogenic variants, and 16 (26.2%) were novel. Mostly affected mutation sites were exonic regions (n=54, 88.5%). The most common mutated exon was exon 38 (n=7, 11.5%), and most of the detected mutations were nonsense mutations (31%). Conclusion: It is one of Turkiye's largest NF1 study groups, where all exons of the NF1 gene were analyzed. This study contributes novel variants to the literature. There was no mutational hotspot region, and no significant relationship between genotype and phenotype was observed. Further studies and large sample sizes are required to better understand the relationship between NF and genetic changes.