BACKGROUND: The genetic etiologies of the hyper-IgE syndromes are diverse. Approximately 60% to 70% of patients with hyper-IgE syndrome have dominant mutations in STAT3, and a single patient was reported to have a homozygous TYK2 mutation. In the remaining patients with hyper-IgE syndrome, the genetic etiology has not yet been identified. OBJECTIVES: We aimed to identify a gene that is mutated or deleted in autosomal recessive hyper-IgE syndrome. METHODS: We performed genome-wide single nucleotide polymorphism analysis for 9 patients with autosomal-recessive hyper-IgE syndrome to locate copy number variations and homozygous haplotypes. Homozygosity mapping was performed with 12 patients from 7 additional families. The candidate gene was analyzed by genomic and cDNA sequencing to identify causative alleles in a total of 27 patients with autosomal-recessive hyper-IgE syndrome. RESULTS: Subtelomeric biallelic microdeletions were identified in 5 patients at the terminus of chromosome 9p. In all 5 patients, the deleted interval involved dedicator of cytokinesis 8 (DOCK8), encoding a protein implicated in the regulation of the actin cytoskeleton. Sequencing of patients without large deletions revealed 16 patients from 9 unrelated families with distinct homozygous mutations in DOCK8 causing premature termination, frameshift, splice site disruption, and single exon deletions and microdeletions. DOCK8 deficiency was associated with impaired activation of CD4+ and CD8+T cells. CONCLUSION: Autosomal-recessive mutations in DOCK8 are responsible for many, although not all, cases of autosomal-recessive hyper-IgE syndrome. DOCK8 disruption is associated with a phenotype of severe cellular immunodeficiency characterized by susceptibility to viral infections, atopic eczema, defective T-cell activation and T(h)17 cell differentiation, and impaired eosinophil homeostasis and dysregulation of IgE.
Large deletions and point mutations involving the dedicator of cytokinesis 8 (DOCK8) in the autosomal-recessive form of hyper-IgE syndrome / K.R. Engelhardt, S. McGhee, S. Winkler, A. Sassi, C. Woellner, G. Lopez-Herrera, A. Chen, H.S. Kim, M.G. Lloret, I. Schulze, S. Ehl, J. Thiel, D. Pfeifer, H. Veelken, T. Niehues, K. Siepermann, S. Weinspach, I. Reisli, S. Keles, F. Genel, N. Kutukculer, Y. Camcioğlu, A. Somer, E. Karakoc-Aydiner, I. Barlan, A. Gennery, A. Metin, A. Degerliyurt, M.C. Pietrogrande, N. Yeganeh, Z. Baz, S. Al-Tamemi, C. Klein, J.M. Puck, S.M. Holland, E.R. McCabe, S. Grimbacher, T.A. Chatila. - In: JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY. - ISSN 0091-6749. - 124:6(2009 Dec), pp. 1289-1302.
Large deletions and point mutations involving the dedicator of cytokinesis 8 (DOCK8) in the autosomal-recessive form of hyper-IgE syndrome
M.C. Pietrogrande;
2009
Abstract
BACKGROUND: The genetic etiologies of the hyper-IgE syndromes are diverse. Approximately 60% to 70% of patients with hyper-IgE syndrome have dominant mutations in STAT3, and a single patient was reported to have a homozygous TYK2 mutation. In the remaining patients with hyper-IgE syndrome, the genetic etiology has not yet been identified. OBJECTIVES: We aimed to identify a gene that is mutated or deleted in autosomal recessive hyper-IgE syndrome. METHODS: We performed genome-wide single nucleotide polymorphism analysis for 9 patients with autosomal-recessive hyper-IgE syndrome to locate copy number variations and homozygous haplotypes. Homozygosity mapping was performed with 12 patients from 7 additional families. The candidate gene was analyzed by genomic and cDNA sequencing to identify causative alleles in a total of 27 patients with autosomal-recessive hyper-IgE syndrome. RESULTS: Subtelomeric biallelic microdeletions were identified in 5 patients at the terminus of chromosome 9p. In all 5 patients, the deleted interval involved dedicator of cytokinesis 8 (DOCK8), encoding a protein implicated in the regulation of the actin cytoskeleton. Sequencing of patients without large deletions revealed 16 patients from 9 unrelated families with distinct homozygous mutations in DOCK8 causing premature termination, frameshift, splice site disruption, and single exon deletions and microdeletions. DOCK8 deficiency was associated with impaired activation of CD4+ and CD8+T cells. CONCLUSION: Autosomal-recessive mutations in DOCK8 are responsible for many, although not all, cases of autosomal-recessive hyper-IgE syndrome. DOCK8 disruption is associated with a phenotype of severe cellular immunodeficiency characterized by susceptibility to viral infections, atopic eczema, defective T-cell activation and T(h)17 cell differentiation, and impaired eosinophil homeostasis and dysregulation of IgE.
Pubblicazioni consigliate
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
