Other uncommon mutations are in TP53 (9% of cases), ATP-dependent helicase (ATRX) (in 6% of MM), and Phosphatase and tensin homolog (PTEN) inactivation through methylation of the PTEN promoter, a rare occurrence involved in the development of Sinonasal MM [44]. This evidence concerns the gene TP53 and Miyoshi myopathy.