Fig. 5.

Comprehensive mutation analysis of all three genes, LZTR1, SMARCB1, and NF2, in patients with schwannomatosis should be performed to identify the complete mutational spectra and the number of mutational hits that affect these genes. This comprehensive testing may help to classify the tumours according to their mutation-profile. The mutation analysis should also include methods, such as next-generation sequencing, which are well suited to detect somatic mosaicism with mutant cells present in low proportions. This approach should identify tumour heterogeneity and help to distinguish between mosaic NF2 and schwannomatosis, since some NF2 patients with somatic mosaicism for an NF2 gene mutation fulfil the diagnostic criteria for schwannomatosis (Plotkin et al. 2013)