SMARCB1 and schwannomatosis: Although inclusion of LZTR1-SWN could erroneously inflate the birth prevalence estimates for clinical NF2-SWN these rates have been adjusted for in the recent estimates [36, 43] and may not account for the 50% of new onset schwannomatosis cases without identifiable germline SMARCB1 or LZTR1 variants that on analysing ≥ 2 tumours have mosaic NF2-SWN [27, 36].