In 2005, the molecular basis of chronic myeloproliferative diseases was described, with the JAK2V617F variant (dbSNP ID: rs77375493) characterized by a transversion-type base substitution at nucleotide 1849 (1849G > T) of exon 14 of the JAK2 gene encoding a valine through a phenylalanine at position 617 (V617F) [37,38,39]. This evidence concerns the gene JAK2 and myeloproliferative neoplasm.