Idiopathic myelofibrosis with generalized periostitis in a 4-year-old girl

Transcriptome Analysis of Monozygotic Twin Brothers with Childhood Primary Myelofibrosis

Primary myelofibrosis (PMF) is a chronic myeloproliferative disorder in human bone marrow. Over 50% of patients with myelofibrosis have mutations in JAK2, MPL, or CALR. However, these mutations are rarely detected in children, suggesting a difference in the pathogenesis of childhood PMF. In this study, we investigated the response to drug treatment of a monozygotic twin pair with typical childhood PMF. The twin exhibited different clinical outcomes despite following the same treatment regimen. The transcriptomic profiles of patient samples after drug treatment (E2 and Y2) were significantly different between the twin pair, which is consistent with the observation that the drug treatment was effective only in the younger brother, despite the twin being genetically identical. Bioinformatics analysis of the drug-responsive genes showed that the JAK-STAT pathway was activated in the cured younger brother, which is opposite to the pathway inhibition observed in adult PMF cases following treatment. Moreover, apoptosis and cell cycle processes were both significantly influenced by drug treatment in the sample of younger brother (Y2), implying their potential association with the pathogenesis of childhood PMF. Gene mutations in JAK2, MPL, or CALR were not observed; however, mutations in genes including SRSF2 and SF3B1 occurred in this twin pair with childhood PMF. Gene fusion events were extensively screened in the twin pair samples and the occurrence of IGLV2-14-IGLL5 gene fusion was confirmed. The current study reported at transcriptomic level the different responses of monozygotic twin brothers with childhood PMF to the same androgen/prednisone treatment regimen providing new insights into the potential pathogenesis of childhood PMF for further research and clinical applications.

CALR mutation screening in pediatric primary myelofibrosis

BACKGROUND

Primary myelofibrosis (PMF) is quite rare in children. Mutations of JAK2(V617F) or MPL(W515K/L) were absent in pediatric patients with PMF according to previous studies. Recently, mutations in calreticulin (CALR) were described in adult patients with JAK2/MPL-unmutated PMF. Our study aimed to analyze the clinical and genetic features of Chinese pediatric patients with PMF.

PROCEDURES

We retrospectively investigated 14 pediatric patients diagnosed as PMF according to WHO 2008 criteria. Direct sequencing was performed for the existence of genetic alterations in JAK2, MPL, TET2, CBL, ASXL1, IDH1, IDH2, SRSF2, EZH2, DNMT3A and CALR.

RESULTS

In our cohort, all patients had anemia, three patients (21%) had splenomegaly, six patients (43%) had micromegakaryocytes at time of diagnosis. No patient had spontaneous remission and six patients (43%) transformed to acute myelocytic leukemia. In nine patients with evaluable cytogenetic information, three subjects (33%) had abnormal karyotypes. The median survival from time of diagnosis was 28 months. Seven patients (50%) had type 2 mutations of CALR. No patient had mutations in the other candidate genes. There was no statistical differences in age, gender, hemoglobin, WBC, neutrophil and platelet counts, percentage of circulating blast, overall survival and leukemia transformation between patients with and without CALR mutation.

CONCLUSION

Our study documented that Chinese pediatric patients with PMF in our cohort had its own clinical characteristics and poor outcome. CALR mutations were detected in 50% of our pediatric patients with PMF. Based on our study, CALR mutations screening could be used as molecular marker for diagnosis of pediatric patients with PMF.

VPS 45-associated primary infantile myelofibrosis--successful treatment with hematopoietic stem cell transplantation

PMF of infancy is a recently described autosomal recessive disorder presenting with severe bone marrow failure, accelerated neutrophil apoptosis, and significant platelet dysfunction, caused by a mutation in the VPS45 gene. In this study, we update our group of patients with PMF, highlighting different aspects of this disease, and evaluating the effectiveness of HSCT for the treatment of this disorder. Update of clinical data, hematological features, molecular studies, treatment and final outcome of four children diagnosed with VPS 45-associated PMF of infancy. The patients described had clinical and hematological findings consistent with MF. Molecular studies showed that all patients were homozygous for the Thr224Asn mutation in the VPS 45 gene. HSCT was carried out in three patients and was successful in two. VPS 45-associated MF is a novel primary immune deficiency that can be successfully corrected by HSCT if applied early in the course of disease using appropriate conditioning. The diagnosis of VPS 45-associated PMF should be considered in all children presenting with SCN with subsequent development of pancytopenia. Long-term follow-up of these patients is necessary to identify extra-hematological manifestations of VPS45 deficiency.

Stem cell transplantation in primary myelofibrosis of childhood

Fewer than 40 cases of primary myelofibrosis have been reported in children; hematopoietic stem cell transplantation is the only available curative therapy for this disease. Here, we describe the case of a female infant diagnosed with primary myelofibrosis at the age of 6 months; she underwent successful matched unrelated bone marrow transplantation with complete resolution of disease. We discuss some unique characteristics of primary myelofibrosis in children and review outcome data for children with this disease.

Clinical, histopathologic, and genetic features of pediatric primary myelofibrosis--an entity different from adults

Primary myelofibrosis is a chronic myeloproliferative neoplasm characterized by cytopenias, leukoerythroblastosis, extramedullary hematopoiesis, hepatosplenomegaly and bone marrow fibrosis. Primary myelofibrosis is a rare disorder in adults; children are even less commonly affected by this entity, with the largest pediatric case series reporting on three patients. Most literature suggests spontaneous resolution of myelofibrosis without long term complications in the majority of affected children. We describe the clinical, pathologic, and molecular characteristics and outcomes of nineteen children with primary myelofibrosis treated in our center from 1984 to 2011. Most patients had cytopenia significant enough to require supportive therapy. No child developed malignant transformation and only five of the 19 children (26%) had spontaneous resolution of disease. Sequence analyses for JAK2V617F and MPLW515L mutations were performed on bone marrow samples from 17 and six patients, respectively, and the results were negative. In conclusion, analysis of this large series of pediatric patients with primary myelofibrosis demonstrates distinct clinical, hematologic, bone marrow, and molecular features from adult patients.

Myelofibrosis in children: experience at a single tertiary care center in India

The authors describe 10 cases of myelofibrosis diagnosed and managed at their center over 16 years. There were 2 and 8 cases, respectively, of primary and secondary myelofibrosis. All patients presented with fever, pallor, hepatosplenomegaly, and/or lymphadenopathy. Hodgkin's lymphoma (n = 4), neuroblastoma (n = 1), thrombasthenic thrombopathy (n = 1), and retroperitoneal-mass (n = 1) were causal in 7 patients, whereas the diagnosis could not be established in a sole case of secondary myelofibrosis. Patients were managed with chemotherapy and appropriate care. However, outcome was poor. The authors emphasize variable clinical-laboratory spectrum of myelofibrosis, highlight management concerns, and demonstrate that prognosis/outcome depends upon appropriate management of the underlying condition.

Hypertrophic osteoarthropathy: a palindrome with a pathogenic connotation

PURPOSE OF REVIEW

The review seeks to update advances on the pathogenesis of hypertrophic osteoarthropathy, describe a previously unrecognized palindrome that occurs in hypertrophic osteoarthropathy and that may have pathogenic implications, and review the role of bisphosphonates in the treatment of this condition.

RECENT FINDINGS

Some patients with primary hypertrophic osteoarthropathy display an interesting palindrome. Many years after the onset of the osteoarthropathy, they develop diseases that in other circumstances are known to generate secondary hypertrophic osteoarthropathy. This palindrome has been reported in cases of patent ductus arteriosus, Crohn's disease and myelofibrosis. Additionally, primary hypertrophic osteoarthropathy and POEMS syndrome share important clinical features. The many diseases associated with hypertrophic osteoarthropathy have in common abnormal production of vascular endothelial growth factor. This cytokine has been proposed to play a major role in the pathogenesis of Crohn's disease, myelofibrosis and POEMS syndrome. A controlled study showed that vascular endothelial growth factor is abnormally expressed in cases of hypertrophic osteoarthropathy. The biologic effects of vascular endothelial growth factor may explain hypertrophic osteoarthropathy histological features. Several isolated reports suggest that pamidronate is effective in relieving painful osteoarthropathy.

SUMMARY

Hypertrophic osteoarthropathy is a palindromic syndrome. Anomalous vascular endothelial growth factor expression may explain this phenomenon. Bisphosphonates may have a role in the symptomatic treatment of hypertrophic osteoarthropathy.