Background: The metabolic syndrome (MS) is associated with insulin resistance (IR), a systemic lowgrade inflammatory state and endothelial dysfunction. These disorders may arise at a very early age in obese children. This study aimed to investigate the relationship between endothelial dysfunction and both IR and inflammation in prepubertal obese children. Methods and results: Von Willebrand factor (vWF) and soluble intercellular adhesion molecule-1 (sICAM-1) levels were measured in 46 obese prepubertal children aged 6-9, and in 46 non-obese, ageand sex-matched controls; the possible association of these levels with MS, various inflammatory biomarkers and plasminogen activator inhibitor-1 (PAI-1) was analyzed. Obese children displayed significantly elevated values for sICAM-1 (PZ0.008), vWF (PZ0.034), insulin (PZ0.006), homeostasis model assessment for IR (HOMA-IR; PZ0.003), C-reactive protein (CRP) (P!0.001), PAI-1 (PZ0.002) and leptin (P!0.001). Nonsignificant differences were found in interleukin 6 (IL-6) levels. In the obese group, sICAM-1 showed a positive correlation with insulin (PZ0.013), HOMA-IR (PZ0.015), CRP (PZ0.020), IL-6 (PZ0.023) and PAI-1 (PZ0.015). Corrected for age and sex, insulin, HOMA-IR, IL-6 and CPR were found to be independent predictive factors for sICAM-1. Conclusions: Prepubertal obese children displayed alterations indicative of endothelial dysfunction as well as disorders typical of MS. An association was established between endothelial dysfunction, IR, inflammation and inappropriate fibrinolysis in the children studied.
Acute myeloid leukemia with myelodysplasia-related changes (AML-MRC) are poor outcome leukemias. Its diagnosis is based on clinical, cytogenetic, and cytomorphologic criteria, last criterion being sometimes difficult to assess. A high frequency of ASXL1 mutations have been described in this leukemia. We sequenced ASXL1 gene mutations in 61 patients with AML-MRC and 46 controls with acute myeloid leukemia without other specifications (AML-NOS) to identify clinical, cytomorphologic, and cytogenetic characteristics associated with ASXL1 mutational status. Mutated ASXL1 (ASXL1+) was observed in 31% of patients with AML-MRC compared to 4.3% in AML-NOS.Its presence in AML-MRC was associated with older age, a previous history of myelodysplastic syndrome (MDS) or myelodysplastic/myeloproliferative neoplasms (MDS/ MPN), leukocytosis, presence of micromegakaryocytes in bone marrow, lower number of blasts in bone marrow, myelomonocytic/monocytic morphological features and normal karyotype. ASXL1 mutation was not observed in patients with myelodysplastic syndrome-related cytogenetic abnormalities or TP53 mutations. Differences in terms of overall survival were found only in AML-MRC patients without prior MDS or MDS/ MPN and with intermediate-risk karyotype, having ASXL1+ patients a worst outcome than ASXL1−. We conclude that the ASXL1 mutation frequency is high in AML-MRC patients being its presence associated with specific characteristics including morphological signs of dysplasia. This association raises the possible role of ASXL1 as a surrogate marker in AML-MRC, which could facilitate the diagnosis of patients within this group when the karyotype is normal, and especially when the assessment of multilineage dysplasia morphologically is difficult. This mutation could be used as a worst outcome marker in de novo AML-MRC with intermediate-risk karyotype. K E Y W O R D S AML-MRC, ASXL1, myelodysplasia, myeloid leukemia 3638 | PRATS-MARTÍN eT Al.
An autosomal dominant form of congenital dyserythropoietic anemia type III (CDA III) is caused by a missense mutation in the KIF23 gene whose protein product, mitotic kinesin-like protein (MKLP1), is part of the centralspindlin complex involved in cytokinesis. Several case reports suggested the existence of an autosomal recessive inheritance form of CDA III so far not genetically characterized. By means of whole exome sequencing in a Spanish CDA III family with healthy parents, we identified in the male proband a novel homozygous missense mutation p.Pro432Ser in the RACGAP1 gene, which encodes for the RACGAP1 protein (Rac GTPase-activating protein 1, also known as MgcRacGAP or CYK-4), the partner of MKLP1 in the centralspindlin complex. A second CDA III Spanish patient has a different rare and novel homozygous missense mutation, p.Thr220Ala, in the RACGAP1 gene. Both patients presented with macrocytic anemia, aberrant multinucleated erythroblasts in the bone marrow typically seen in CDA III cases, no iron overload and skull defects secondary to severe anemia. Silencing of RACGAP1 using siRNA in HeLa cells mimics the cytokinesis defect observed in the bone marrow of our patients. Both mutations disrupt normal cytokinesis and alter the GTPase balance in patients' cells. We conclude that the autosomal recessive form of CDA type III is caused by mutations in the RACGAP1 gene, encoding for RACGAP1 protein, which is the partner of MKLP1 in the centralspindlin complex critical for cytokinesis and now both proteins are associated with CDA type III.
Figure 1 Figure 1.
Disclosures
No relevant conflicts of interest to declare.
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