Abstract

Plexiform neurofibromas (PNFs) are distinct lesions in neurofibromatosis type 1 (NF1) patients and may arise anywhere along a nerve. PNFs occur in approximately 50% of individuals with NF1 and they have a capacity to transform into malignant peripheral nerve sheath tumors (MPNSTs) in 8%-13% of NF1 patients. In this study, we report four cases of NF1 with a PFN manifestation and the mutational analysis of the NF1 gene. The patients were from two families from Erode district, Tamil Nadu, South India. All the cases fulfilled the National Institutes of Health (NIH) diagnostic criteria of NF1, and had the major features of NF1 such as café-au-lait spots (CALS). cutaneous neurofibromas, plexiform neurofibromas and axillary freckling. Short stature is the minor NF1 feature that occurred in all the four cases. Mutations in the NF1 gene was detected by isolating the genomic DNA from each patient’s blood sample and amplifying the NF1 gene using the polymerase chain reaction (PCR) technique. Two NF1 mutations c.5242C˃T and c.2033_2034insC were detected in exon 13 and 29 respectively, by the Sanger sequencing method. Despite all the four patients had a PNF in a different part of the body, and those from the same family shared the same NF1 mutation, no genotype-phenotype correlations associated with the PNF have been identified.

Keywords: Plexiform neurofibroma; NF1 gene; Café-au-lait spots

Abbreviations: CALS: Café-au-lait Spots; MPNST: Malignant Peripheral Nerve Sheath Tumor; MRI: Magnetic Resonance Imaging; NF1: Neurofibromatosis Type 1; NIH: National Institutes of Health; PCR: Polymerase Chain Reaction; PNF: Plexiform Neurofibroma; YR: Year.