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

Abstract

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 including <i>NF1</i>, <i>NF2</i>, <i>SPRED1</i>, <i>SMARCB1</i>, and <i>LZTR1</i> genes on Ion Torrent. Together with NGS, the Multiplex Ligation-Dependent Probe Amplification Analysis (MLPA) method was performed to rule out large deletions/duplications in <i>NF1</i> gene; 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 in <i>NF1</i> gene in 168 cases. A <i>SPRED1</i> pathogenic variant was also found in one child and in a one year old boy, both <i>NF2</i> and <i>LZTR1</i> pathogenic variants were observed; in addition, we identified five <i>LZTR1</i> pathogenic variants in three children and two adults. Six <i>NF1</i> pathogenic 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.