# NF1 with 47,XYY mosaicism diagnosed by mandibular neurofibromas

## TL;DR

A patient with Neurofibromatosis type 1 and 47,XYY mosaicism was diagnosed through skin and jaw tumors.

## Contribution

A novel pathogenic NF1 mutation was identified in a patient with 47,XYY mosaicism.

## Key findings

- Café-au-lait macules and mandibular neurofibromas led to the diagnosis of NF1.
- A novel frameshift mutation in the NF1 gene was detected via targeted sequencing.
- The patient also exhibited 47,XYY mosaicism, a rare chromosomal abnormality.

## Abstract

Neurofibromatosis type 1 (NF1) is an autosomal dominant nevus disease characterized by multiple manifestations, primarily café-au-lait macules and neurofibromas. Here, we present the case of an NF1 patient with 47,XYY mosaicism whose diagnosis was prompted by café-au-lait macules on the skin and mandibular neurofibromas. Targeted next-generation sequencing of the patient’s blood sample revealed a novel frameshift mutation in NF1 (NM_000267.3:c.6832dupA:p.Thr2278Asnfs*8) that is considered a pathogenic variant.