NF2 and meningioma: In parallel, multiple studies have also shown a variable frequency (between 14% and 78% of the cases) of NF2 gene mutations in heterogeneous series of meningiomas consisting of between 12 to 170 patients [18,27], some of these reports specifically focusing on the investigation of particular subsets of patients such as recurrent meningiomas [6], rare histopathological subtypes [9] or patients affected by multiple meningiomas [12].