1. Among the monosomy 22 cases, no additional NF2 mutations could be identified in 35% (17 out of 49) of tumors.

2. RESULTS: Monosomy 22 was the predominant finding, detected in 47% of meningiomas.

3. The abnormal is concerned in trisomy, monosomy, Robertsonian translocation, reciprocal translocation and rearrange.

4. Monosomy of chromosome 9 was consistently present in all cells. Chromosome 7 was trisomic or tetrasomic in the cells.

5. Absence of one chromosome of a pair is called monosomy for that chromosome.