Transcriptional profiling in alopecia areata defines immune and cell cycle control related genes within disease-specific signatures
GENOMICS
Authors: Subramanya, Raghunandan Dudda; Coda, Alvin B.; Sinha, Animesh A.
Abstract
Alopecia areata (AA) is a non-scarring inflammatory hair loss disease with a complex autoimmune etiopathogenesis that is poorly understood. In order to investigate the pathogenesis of AA at the molecular level, we examined the gene expression profiles in skin samples from lesional (n = 10) and non-lesional sites (n = 10) of AA patients using Affymetrix Hu95A-v2 arrays. 363 genes were found to be differentially expressed in AA skin compared to non-lesional skin; 97 were up-regulated and 266 were down-regulated. Functional classification of the differentially expressed genes (DEGs) provides evidence for T-cell mediated immune response (CCL5, CXCL10, CD27, ICAM2, ICAM3, IL7R, and CX3CL1), and a possible humoral mechanism (IGHG3, IGHM, and CXCR5) in AA. We also find modulation in gene expression favoring cellular proliferation arrest at various levels (FGF5, FGF18, EREG, and FOXC2) with apoptotic dysregulation (LCK, TNF, TRAF2, and SFN) and decreased expression of hair follicle structural proteins. Further analysis of patients with AAT (<1 year duration, n = 4) and MP (>1 year duration, n = 6) of disease revealed 262 DEGs distinctly separating the 2 groups, indicating the existence of gene profiles unique to the initial and later stages of disease. (C) 2010 Elsevier Inc. All rights reserved.
Genetic Approaches for Definitive Diagnosis of Agammaglobulinemia in Consanguineous Families
JOURNAL OF CLINICAL IMMUNOLOGY
Authors: Ben-Ali, Meriem; Kechout, Nadia; Mekki, Najla; Yang, Jing; Chan, Koon Wing; Barakat, Abdelhamid; Aadam, Zahra; Gamara, Jouda; Gargouri, Lamia; Largueche, Beya; BelHadj-Hmida, Nabil; Nedri, Amel; Ben Ameur, Houcine; Mellouli, Fethi; Boukari, Rachida; Bejaoui, Mohamed; Bousfiha, Aziz; Ben-Mustapha, Imen; Lau, Yu-Lung; Barbouche, Mohamed-Ridha
Abstract
Autosomal recessive agammaglobulinemia (ARA) is a primary immunodeficiency characterized by absent peripheral B cells, severe hypogammaglobulinemia, and absent BTK gene mutations. In ARA, mutations occur in genes encoding the pre-B cell receptor (pre-BCR) or downstream signaling proteins. In this work, we used candidate gene and whole-exome sequencing to investigate the molecular basis of ARA in 6 patients from 4 consanguineous North-African families. Sanger sequencing of candidate genes encoding the pre-BCR components (Iota G Eta Mu, CD79A, CD79B, IGLL1, and VPREB1) was initially performed and determined the genetic defect in five patients. Two novel mutations in IGHM (p.Val378Alafs*1 and p.Ile184Serfs*21) were identified in three patients from two unrelated kindred and a novel nonsense mutation was identified in CD79A (p.Trp66*) in two siblings from a third kindred. Whole-exome sequencing (WES) was performed on the sixth patient who harbored a homozygous stop mutation at position 407 in the RAG2 gene (p.Glu407*). We concluded that conventional gene sequencing, especially when multiple genes are involved in the defect as is the case in ARA, is costly and time-consuming, resulting in delayed diagnosis that contributes to increased morbidity and mortality. In addition, it fails to identify the involvement of novel and unsuspected gene defects when the phenotype of the patients is atypical. WES has the potential to provide a rapid and more accurate genetic diagnosis in ARA, which is crucial for the treatment of the patients.