XXXX Deficiency May Present Clinically as Selective IgA Deficiency.

@entity1 @entity71616 @entity37671 @entity1910 @entity738 @entity71617 @entity828 @entity281 @entity466 @entity792 @entity12656 @entity74 @entity1292 @entity52780 @entity2015
BACKGROUND: @entity52780 deficiency is seen in @entity1 with @entity466 ( @entity466 ) and @entity466 . However, the spectrum of the disease has recently expanded to include a milder phenotype. OBJECTIVE: We analyzed a 4-year-old @entity1 who was initially given the diagnosis of selective @entity2015 (SIgAD) based on immunoglobulin serum levels without any @entity1292 , @entity1910 , @entity828 , @entity792 or @entity738 . The @entity1 was found to be @entity281 ; however, the clinical course was not serious. He produced antiviral antibodies. METHODS: We performed lymphocyte phenotyping, quantification of T cell receptor excision circles (TRECs) and kappa deleting recombination excision circles (KRECs), an analysis of target sequences of @entity52780 , a whole-genome SNP array, an in vitro V(D)J recombination assay, a spectratype analysis of the CDR3 region and a flow cytometric analysis of the bone marrow. RESULTS: Lymphocyte phenotyping demonstrated that the ratio of CD4+ to CD8+ T cells was inverted and the majority of CD4+T cells expressed CD45RO antigens in addition to the almost complete lack of B cells. Furthermore, both TRECs and KRECs were absent. Targeted DNA sequencing and SNP array revealed that the @entity1 carried a deletion of @entity12656 and @entity37671 genes on the paternally-derived chromosome 11, and two maternally-derived novel @entity12656 missense mutations ( @entity71616 , @entity71617 ). In vitro analysis of recombination activity showed that both @entity12656 mutant proteins had low, but residual function. CONCLUSIONS: The current case further expands the phenotypic spectrum of mild presentations of @entity74 , and suggests that TRECs and KRECs are useful markers for detecting hidden severe, as well as mild, cases.
