Immune Deficiency in Jacobsen Syndrome: Molecular and Phenotypic Characterization.

Jacobsen syndrome or JBS (OMIM #147791) is a contiguous gene syndrome caused by a deletion affecting the terminal q region of chromosome 11. The phenotype of patients with JBS is a specific syndromic phenotype predominately associated with hematological alterations. Complete and partial JBS are differentiated depending on which functional and causal genes are haploinsufficient in the patient. We describe the case of a 6-year-old Bulgarian boy in which it was possible to identify all of the major signs and symptoms listed by the Online Mendelian Inheritance in Man (OMIM) catalog using the Human Phenotype Ontology (HPO). Extensive blood and marrow tests revealed the existence of thrombocytopenia and leucopenia, specifically due to low levels of T and B cells and low levels of IgM. Genetic analysis using whole-genome single nucleotide polymorphisms (SNPs)/copy number variations (CNVs) microarray hybridization confirmed that the patient had the deletion arr[hg19]11q24.3q25(128,137,532-134,938,470)x1 in heterozygosis. This alteration was considered causal of partial JBS because the essential BSX and NRGN genes were not included, though 30 of the 96 HPO identifiers associated with this OMIM were identified in the patient. The deletion of the FLI-1, ETS1, JAM3 and THYN1 genes was considered to be directly associated with the immunodeficiency exhibited by the patient. Although immunodeficiency is widely accepted as a major sign of JBS, only constipation, bone marrow hypocellularity and recurrent respiratory infections have been included in the HPO as terms used to refer to the immunological defects in JBS. Exhaustive functional analysis and individual monitoring are required and should be mandatory for these patients.

Egg white specific IgE levels in serum as clinical reactivity predictors in the course of egg allergy follow-up.

It is thought that the natural evolution of egg allergy has a good tolerance prognosis. However, there are few follow-up studies that determine the exact probability of tolerance. The aim of this study was to determine the likelihood that children younger than 2,5 years of age with allergy to egg would eventually have tolerance to it and to analyze if monitoring egg white-specific IgE level over time could be used as a predictor for determining when patients develop clinical tolerance. We performed a retrospective study of our last 42 patients diagnosed with egg allergy. Annual follow-up comprised prick testing, specific IgE (sIgE) and provocation testing with egg white (EW), allowing the prediction of tolerance at that timepoint with a probability of >or=95%. Median survival time was 48 months. The mean initial and final levels of EW sIgE were lower in the patients that reached tolerance (p<0.05). EW sIgE levels of 1.52, 1.35, and 2.59 KUA/l, respectively predicted clinical reactivity (PPV > 95%) at the different follow-up timepoints analyzed (25-36, 37-48 and 49-60 months. Quantification of egg white specific IgE levels is a useful test for diagnosing symptomatic allergy to egg white in the pediatric population and could eliminate the need to perform oral challenges tests in a significant number of children.