title: JAK2 V617F-positive essential thrombocythemia in a patient with Klinefelter syndrome: a case report.
abstract: Klinefelter syndrome (KS) is the most commonly diagnosed X chromosome aneuploid syndrome among males. The association between hematologic malignancies such as non-Hodgkin lymphoma and leukemia and KS has been established recently on the basis of numerous case reports and a large cohort study. The risk of chronic myeloproliferative disease (MPD) as a hematologic malignancy in KS, however, has not been evaluated to date. Moreover, to our knowledge, there is only one case report that observed MPD in a patient with KS. Even though the Janus kinase 2 (JAK2) mutation was considered the primary cause in the pathogenesis of MPD, the mutation status was not described in that report. We found JAK2 V617F mutation-positive essential thromobocythemia (ET) in a patient with KS. To the best of our knowledge, this case represents the first case report of JAK2 V617F mutation in a patient with KS. Furthermore, we also suggest the hypothesis that X chromosome aneuploidy as a "pre-JAK2" cytogenetic change may be associated with the development of clonal hematopoiesis and carcinogenesis, because of the finding of higher oncogenic potential of extra X chromosome. In this study, we present the first report of JAK2 V617F-positive ET in a patient with KS, as well as a review of the relevant literature.
authors.affiliation: Division of Hematology/Oncology, Department of Internal Medicine, Chonbuk National University Medical School, Jeonju, 561-712 Korea.
authors.forename: Ho-Young
authors.initials: HY
authors.lastname: Yhim
authors.forename: Hee Sun
authors.initials: HS
authors.lastname: Kim
authors.forename: Ji-Youn
authors.initials: JY
authors.lastname: Sohn
authors.forename: Min-Ju
authors.initials: MJ
authors.lastname: Song
authors.forename: Na-Ri
authors.initials: NR
authors.lastname: Lee
authors.forename: Eun-Kee
authors.initials: EK
authors.lastname: Song
authors.forename: Sam-Im
authors.initials: SI
authors.lastname: Choi
authors.forename: Chang-Yeol
authors.initials: CY
authors.lastname: Yim
authors.forename: Jae-Yong
authors.initials: JY
authors.lastname: Kwak
mesh_terms: D000328:Adult; D019943:Amino Acid Substitution / Q000235:genetics; D002871:Chromosome Banding; D006801:Humans; D053614:Janus Kinase 2 / Q000235:genetics* / Q000378:metabolism; D007713:Klinefelter Syndrome / Q000150:complications / Q000235:genetics*; D008297:Male; D020125:Mutation, Missense / Q000502:physiology; D010649:Phenylalanine / Q000235:genetics; D013920:Thrombocythemia, Essential / Q000150:complications / Q000235:genetics*; D014633:Valine / Q000235:genetics
chemical_list: D010649:Phenylalanine; C507924:JAK2 protein, human; D053614:Janus Kinase 2; D014633:Valine