In addition to Cdkn2a on chromosome 5, another observation relating karyotypic alterations to aggressiveness concerns the NF2 gene coding for merlin, the second major alteration in human MM, which was shown to be the target tumor suppressor gene of 22q12 loss and found to be mutated in the majority of human MM [64]. The gene discussed is CDKN2A; the disease is Miyoshi myopathy.