X Chromosome Inactivation Patterns in Normal Females

Racchi, Omar; Mangerini, Rosa; Rapezzi, Davide; Rolfo, Michela; Gaetani, Gian Franco; Ferraris, Anna Maria

doi:10.1006/bcmd.1998.0213

Cited by 42 publications

(40 citation statements)

References 22 publications

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“…In 4 of 6 patients with clonal granulocytes we found polyclonal T cells, excluding constitutive allelic skewing. [20][21][22][23] Since 4 of 7 informative patients were older than 65, we cannot exclude that in some of them age-related skewing might have contributed to the apparent clonality in granulocytes. However, in a recent report, Levine et al showed that the incidence of neutrophil clonality in patients with ET is the same in age groups below and above 60 years of age and based on statistical analysis reached the same conclusions as presented here.…”

Section: Resultsmentioning

confidence: 99%

Acquisition of the V617F mutation of JAK2 is a late genetic event in a subset of patients with myeloproliferative disorders

Královics

Teo

et al. 2006

Blood

252

192

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An acquired gain-of-function mutation in the Janus kinase 2 (JAK2-V617F) is frequently found in patients with myeloproliferative disorders (MPDs). To test the hypothesis that JAK2-V617F is the disease-initiating mutation, we examined whether all cells of clonal origin carry the JAK2-V617F mutation. Using allele-specific polymerase chain reaction (PCR) assays for the JAK2 mutation and for the X-chromosomal clonality markers IDS and MPP1, we found that the percentage of granulocytes and platelets with JAK2-V617F was often markedly lower than the percentage of clonal granulocytes determined by IDS or MPP1 clonality assays in female patients. Using deletions of chromosome 20q (del20q) as an autosomal, X-chromosome-independent clonality marker, we found a similar discrepancy IntroductionClonal hematopoiesis has been recognized as a key pathogenetic feature of myeloproliferative disorders (MPDs). 1 Recently, an acquired somatic mutation in the JAK2 gene resulting in a valine-to-phenylalanine substitution at position 617 (JAK2-V617F) was described in patients with MPDs. [2][3][4][5][6] This discovery implied that the presence of the JAK2-V617F mutation could represent the primary causative lesion in MPDs. However, some of the clinical and genetic data suggested that the role of the JAK2-V617F mutation in the MPD pathogenesis could be more complex and led us to propose 2 alternative models for the role of JAK2-V617F in the clonal evolution of MPDs. 5 The first model assumed that JAK2-V617F alone is sufficient to cause MPDs. The second model predicted that MPDs are caused by a mutation in an as-yetunknown gene that precedes the acquisition of the JAK2-V617F mutation and that JAK2-V617F represents a later event in the disease progression. 5 One of the predictions of the first model is that the JAK2-V617F mutation should be present in all cells that represent the MPD clone, whereas according to the second model, only a proportion of clonal cells carry the JAK2-V617F mutation. Here we present data in support of the second model in at least a proportion of patients with MPDs. Cell separations, RNA and DNA isolation, microsatellite PCR All blood samples were processed within 4 hours after collection. Isolation of granulocytes, T lymphocytes, platelets, buccal mucosa, RNA, and DNA, as well as cDNA synthesis, were performed as described. 5,8,9 Loss of heterozygosity on chromosome 20q was determined by microsatellite polymerase chain reaction (PCR) with the markers D20S96 and D20S119 derived from the minimal deleted region. 10 Study design Detection of JAK2-V617FThe allele-specific PCR for JAK2 genotyping was carried out using 20 ng genomic DNA, 45 nM forward primer JAK2-F, and 22.5 nM each of the allele-specific reverse primers JAK2-R-T and JAK2-R-G (Table S1, available at the Blood website; see the Supplemental Materials link at the top of the online article) in a buffer containing 50 mM KCl, 10 mM Tris pH 8.0, and 1.5 mM MgCl 2 . Thirty PCR cycles with denaturing at 94°C for 30 seconds, annealing at 61°C for 30 seconds, and ...

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Section: Resultsmentioning

confidence: 99%

Acquisition of the V617F mutation of JAK2 is a late genetic event in a subset of patients with myeloproliferative disorders

Královics

Teo

et al. 2006

Blood

252

192

View full text Add to dashboard Cite

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“…Of the 27, 5 were excluded from the study due to excess skewing, defined as greater than or equal to 90% of the cells with the same X-chromosome active. 11 Clonality status was therefore determined in PMNs and MNCs by XCIP analysis in 22 patients (Table 1). PMNs expressed a monoclonal XCIP in 9 (69%) of 13 subjects with ET and in 6 (67%) of 9 with PV.…”

Section: Resultsmentioning

confidence: 99%

“…Granulocytes (PMNs) and mononuclear cells (MNCs) were purified from peripheral blood according to standard methods. 11 All samples were obtained after informed consent following the guidelines of the Institutional Review Board of the University of Genova.…”

Section: Study Design Patientsmentioning

confidence: 99%

High telomerase activity in granulocytes from clonal polycythemia vera and essential thrombocythemia

Ferraris

Mangerini

Pujić

et al. 2005

Blood

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“…short report according to previously described methods (Racchi et al, 1998). Telomere [terminal restriction fragment (TRF)] length was determined in PMNs and MNCs of each patient.…”

Section: Discussionmentioning

confidence: 99%

Clonal granulocytes in polycythaemia vera and essential thrombocythaemia have shortened telomeres

et al. 2005

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The purpose of this study was to evaluate telomere length in peripheral blood granulocytes and mononuclear cells collected from 22 women with polycythaemia vera (PV) and essential thrombocythaemia (ET). PV and ET are chronic myeloproliferative diseases whose heterogeneity of stem cell origin and clonal development has been established through analysis of X-chromosome inactivation patterns. The results from clonality assay and determination of telomere length show that only clonal granulocytes have shortened telomeres

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X Chromosome Inactivation Patterns in Normal Females

Cited by 42 publications

References 22 publications

Acquisition of the V617F mutation of JAK2 is a late genetic event in a subset of patients with myeloproliferative disorders

Acquisition of the V617F mutation of JAK2 is a late genetic event in a subset of patients with myeloproliferative disorders

High telomerase activity in granulocytes from clonal polycythemia vera and essential thrombocythemia

Clonal granulocytes in polycythaemia vera and essential thrombocythaemia have shortened telomeres

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