Simultaneous Detection of NF1 , SPRED1 , LZTR1 , and NF2 Gene Mutations by Targeted NGS in an Italian Cohort of Suspected NF1 Patients.

Neurofibromatosis type 1 (NF1) displays overlapping phenotypes with other neurocutaneous diseases such as Legius Syndrome. Here, we present results obtained using a next generation sequencing (NGS) panel includingNF1,NF2,SPRED1,SMARCB1, andLZTR1genes on Ion Torrent. Together with NGS, the Multiplex Ligation-Dependent Probe Amplification Analysis (MLPA) method was performed to rule out large deletions/duplications inNF1gene; we validated the MLPA/NGS approach using Sanger sequencing on DNA or RNA of both positive and negative samples. In our cohort, a pathogenic variant was found in 175 patients; the pathogenic variant was observed inNF1gene in 168 cases. ASPRED1pathogenic variant was also found in one child and in a one year old boy, bothNF2andLZTR1pathogenic variants were observed; in addition, we identified fiveLZTR1pathogenic variants in three children and two adults. SixNF1pathogenic variants, that the NGS analysis failed to identify, were detected on RNA by Sanger. NGS allows the identification of novel mutations in five genes in the same sequencing run, permitting unambiguous recognition of disorders with overlapping phenotypes with NF1 and facilitating genetic counseling and a personalized follow-up.