The second subtype is the ‘kinase signaling’ group that is associated with genetic or somatic mutations in the RET proto-oncogene (syndrome MEN 2A, 2B), neurofibromin 1 (NF1), transmembrane protein 127 (TMEM127), MYC-associated factor X (MAX), kinesin-like protein (KIF1BB), receptor tyrosine kinase (MET), GTPase, and Harvey rat sarcoma viral oncogene homolog (HRAS) [36,42]. This evidence concerns the gene NF1 and Down syndrome.