NF2 and meningioma: Consequently, NF2-mutated meningiomas accounted for most cases associated with monosomy 22 (6/9; 67%), including cases with isolated monosomy 22 (4/6; 67%) or with monosomy 22 combined with other chromosomal alterations (2/6, 33%); conversely, among all other cases except three, which were either diploid for chromosome 22, carried del(22q) or had multiple chromosomal losses/gains in the absence of monosomy 22/del(22q), showed no NF2 mutations (0/11; p = 0.03)(Table 1).