IntroductionCongenital Erythrocytosis can be classified as primary, when the defect is intrinsic to the RBC progenitors and independent of the serum erythropoietin (Epo) concentration, or secondary, when the erythrocytosis is the result of an up-regulation of Epo production. Primary erythrocytosis is associated with mutations in the EPOR gene, secondary congenital erythrocytosis can de due to mutations that stabilize the hemoglobin in the oxygenated form or to mutations in the genes that control the transcriptional activation of the EPO gene -VHL, EGLN1, EPAS1. Material and MethodsWith the main objective of describing the etiology and molecular basis of congenital erythrocytosis we have studied 70 consecutive unrelated patients presenting with idiopathic erythrocytosis from our hematology clinic or referred from other centers. According to a study algorithm we have sequenced all the genes described as associated with congenital erythrocytosis. Results and DiscussionErythrocytosis molecular etiology was identify in 25 (36%) of the 70 subjects. High-affinity Hb variants were the most common cause, present in 20% of the cases. New mutations were identified in the JAK2, EPOR, VHL and EGLN1 genes. Conclusions High affinity hemoglobin variants are a very rare cause of secondary congenital erythrocytosis, but it seems likely that their incidence may be underestimated. Our experience shows that in erythrocytosis with a dominant inheritance and normal or inappropriate high Epo levels, the HBB and HBA genes should be the first to be studied. In spite of the seven genes known to be involved in congenital erythrocytosis, the majority of the cases have unknown etiology.

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AAG must be recognized as a pathology affecting pediatric patients. Gastric autoimmune lesion is a chronic process with potential evolution to malignancy. Management guidelines in childhood are not available. Their elaboration is important considering an important risk factor in these age group: a long life expectancy.

Helicobacter pylori infects more than % of the world population and is acquired in infancy. Higher prevalence is found in developing countries, and within geographic areas the predominance correlates inversely with socioeconomic status, especially with living conditions during childhood. Initially, in adults, H. pylori was only associated with gastric diseases, such as peptic ulcer, gastritis, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue M"LT lymphoma, and in childhood, with chronic gastritis and duodenal ulcers in children. Recently, H. pylori has been related to non-gastric diseases, including hematological disorders such as iron deficiency anemia ID" , chronic idiopathic thrombocytopenia cITP , and vitamin " deficiency. H. pylori can trigger autoimmune atrophic gastritis and be responsible initially for an oral iron refractory anemia. Other hematological associations have been made, such as an increased risk of childhood leukemia in children of H. pylori-infected mothers and gastric bleeding in children with coagulation pathologies. H. pylori infection is important in the immune pathogenesis of chronic gastric inflammation and hematological diseases. The diagnostic methodology is based on non-invasive serology, C-urea breath test, stool HP antigen and invasive tests. The scientific community discussed and incorporated in international consensus for the investigation and management of these hematological extragastric pathologies ID", cITP, vitamin " deficiency, and M"LT lymphoma . In children, a similar attitude was obtained in all of these pathologies except for cITP, in which the investigation for H. pylori is not indicated.