Genome-wide gene expression profiling of human narcolepsy

Study objectives: The objectives of this study was perform the global gene expression profiling aimed at identifying differentially expressed genes in the circulating lympho-monocytes of NRLCP patients affected by Narcolepsy with Cataplexy (NRLCP). Based on the tight association to the HLA-DQB1*0602 haplotype in caucasians, it could be hypotesized an immunological dysregulation underlying the pathogenesis of the disease. Design: 10 NRLCP patients with 10 healthy controls were compared. Total RNA isolated from blood specimens was analyzed using microarray technology followed by statistical data analysis to detect genome-wide differential gene expression between patients and controls. Functional analysis of the genelist was performed in order to interpret the biological significance of the data. Results: 173 genes showed significant (p<0.01) differential expression between the two tested conditions. The biological interpretation allowed to categorize differentially expressed genes into main functional groups including includes genes involved in brain development, which could be possibly regarded as peripheral markers of the disease, along with molecular markers of the NRLCP-related dysmetabolic syndrome and immuregulatory molecules. Moreover a striking correlation within selected HLA haplotypes and HLA gene expression was detected, indicating an allele-specific trend of gene expression for the DQB1, DQA1 and DRB4 genes across all the tested subject, regardless of the disease status. Conclusions: the molecular profile associated to NRLCP suggested that molecular markers of neural, metabolic and immunological dysregulation can be detected in blood of NRLCP patients. Moreover, the allele-specific HLA gene expression could suggest a possible direct role of MHCII as a co-factor in the disease etio-pathogenesis

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