The incidence of thrombosis is higher among newborn infants than in any other stage of pediatric development. This fact is the consequence of labile characteristics of the neonatal hemostatic system, in addition to exposure to multiple risk factors and the wide use of vascular catheters. Venous thromboses, which mainly affect the limbs, the right atrium and renal veins, are more frequently seen than arterial thromboses. A stroke may be caused by the occlusion of the arterial flow entering the brain or by occlusion of its venous drainage system. Purpura fulminans is a very severe condition that should be treated as a medical emergency, and is secondary to severe protein C deficiency or, less frequently, protein S or antithrombin deficiency. Most thrombotic events should be managed with antithrombotic therapy, which is done with unfractionated and/or low molecular weight heparins. Purpura fulminans requires protein C replacement and/or fresh frozen plasma infusion. Thrombolytic therapy is done using tissue plasminogen activator and should only be used for life-, or limb-, or organthreatening thrombosis.

The impaired hematopoiesis in acquired aplastic anemia (AA) results from immune-mediated mechanisms. We characterized polymorphisms implicated in controlling type-1 cytokine production in 69 patients with AA. Our data suggest that the studied polymorphisms are not associated with susceptibility in the overall AA population. However, the presence of the higher expressing TNF - 308A allele was associated with younger age (p = 0.0297) and more profound neutropenia (p = 0.0312), and over-represented in patients with very severe AA (p = 0.0168). The higher producing IFNG 12 CA-repeat allele showed strong linkage disequilibrium with the + 874T allele, and was associated with a lower hemoglobin level (p = 0.0351). Also, the presence of at least one higher expressing variant was more frequent among patients responding to immunosuppressive treatment (p = 0.0519). Our findings suggest that the presence of higher expressing variants of tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) in AA patient genotypes could be related to clinical parameters, disease severity and therapy outcomes.

Two distinct syndromes that link α-thalassemia and intellectual disability (ID) have been described: ATR-X, due to mutations in the ATRX gene, and ATR-16, a contiguous gene deletion syndrome in the telomeric region of the short arm of chromosome 16. A critical region where the candidate genes for the ID map has been established. In a pediatric patient with Hemoglobin H disease, dysmorphic features and ID, 4 novel and clinically relevant Copy Number Variants were identified. PCR-GAP, MLPA and FISH analyses established the cause of the α-thalassemia. SNP-array analysis revealed the presence of 4 altered loci: 3 deletions (arr[hg19]Chr16(16p13.3; 88,165-1,507,988) x1; arr[hg19]Chr6(6p21.1; 44,798,701-45,334,537) x1 and arr[hg19]Chr17(17q25.3; 80,544,855-81,057,996) x1) and a terminal duplication (arr[hg19]Chr7(7p22.3-p22.2; 4,935-4,139,785) x3). The -α(3.7) mutation and the ∼1.51 Mb in 16p13.3 are involved in the alpha-thalassemic phenotype. However, the critical region for ATR-16 cannot be narrowed down. The deletion affecting 6p21.1 removes the first 2 exons and part of intron 2 of the RUNX2 gene. Although heterozygous loss of function mutations affecting this gene have been associated with cleidocranial dysplasia, the patient does not exhibit pathognomonic signs of this syndrome, possibly due to the fact that the isoform d of the transcription factor remains unaffected. This work highlights the importance of searching for cryptic deletions in patients with ID and reiterates the need of the molecular analysis when it is associated to microcytic hypochromic anemia with normal iron status.

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The cover image, by Karen G. Scheps et al., is based on the Research Article Multiple copy number variants in a pediatric patient with Hb H disease and intellectual disability, DOI: .

RESUMENLa probabilidad de padecer trombosis es mucho mayor en el período neonatal que en cualquier otra etapa pediátrica. La labilidad del particular sistema hemostático del neonato, sumada a los múltiples factores de riesgo a que está expuesto y la presencia casi constante de catéteres, son responsables de este hecho. Las trombosis venosas son más frecuentes que las arteriales y ocurren principalmente en los miembros, la aurícula derecha y las venas renales. El accidente cerebrovascular puede ser causado por la oclusión del flujo arterial que llega al cerebro o del sistema de drenaje venoso de este. La púrpura fulminans es una patología de altísima gravedad, que debe ser considerada una emergencia médica y se debe a la deficiencia grave de proteína C o, menos frecuentemente, de proteína S o antitrombina. La mayoría de los episodios trombóticos tienen indicación de tratamiento anticoagulante, que se puede realizar con heparina no fraccionada y/o con heparina de bajo peso molecular. La púrpura fulminans requiere terapia de sustitución con proteína C y/o plasma fresco. El tratamiento trombolítico se realiza con activador tisular del plasminógeno y debe quedar reservado solo para aquellas trombosis cuya localización implique compromiso de vida o pérdida de un órgano o de un miembro. veces superior a cualquier otra edad pediátrica, en especial en aquellos niños críticamente enfermos o que precisan catéter central. Este último es, sin duda, el factor de riesgo más importante para el desarrollo de tromboembolismo, tanto arterial como venoso. Aproximadamente, el 90% de los eventos tromboembólicos están asociados a algún tipo de catéter.1,2 Este favorece la ocurrencia de trombosis a través de distintos m e c a n i s m o s , y a s e a a c t u a n d o aisladamente o en forma combinada entre ellos: provoca daño mecánico de la pared vascular y enlentecimiento o interrupción del flujo sanguíneo; está fabricado con material que es potencialmente trombogénico; y es utilizado para infundir sustancias que dañan la pared vascular.3 Los otros factores predisponentes son asfixia perinatal, prematuridad, trastornos cardíacos, sepsis, hipoxia y diabetes materna. Los estados protrombóticos hereditarios juegan un rol poco importante en este período. 4 La incidencia global de tromboembolismo en recién nacidos hospitalizados es de aproximadamente 2,4 por 1000 admisiones.2,5 Se ha comunicado que el 1% de los neonatos con catéte-res presentan síntomas sugestivos de trombosis, 6 y se estima que la incidencia de trombosis asintomática asociada a catéteres está en el orden del 20% al 30%. [7][8][9][10][11] Su manejo adecuado se complica debido a que, generalmente, se extrapolan conductas de tratamiento del adulto. Sin embargo, en los últimos años, se han evidenciado importantes diferencias relacionadas con la edad en esta patología (epidemiología, pruebas diagnósticas, farmacocinética de los antitrombóticos), lo que está permitiendo comenzar a utilizar procedimientos diagnósticos y terapéuticos acordes a este período de la vida. CARACTERÍSTIC...