Exome sequencing revealed C1Q homozygous mutation in Pediatric Systemic Lupus Erythematosus

INTRODUCTION AND OBJECTIVES: Pediatric Systemic Lupus Erythematosus (pSLE) is an autoimmune disorder of children. Early disease onset raises the probability of genetic etiology and it is more severe than adult SLE. PATIENTS AND METHODS: Herein an eight-year-old girl with pSLE from consanguineous parents is reported. RESULTS: Although she was diagnosed as pSLE since the age of two years, Whole Exome Sequencing (WES) revealed a rare stop-gained C>T mutation in C1QA gene. The variant was validated and segregated in patient and the family. Furthermore, serum levels of the C1q protein were measured and found to be much lower than normal ranges. CONCLUSIONS: This study indicated that C1Q deficiency should be considered as a differential diagnosis of pSLE. Therefore, measurement of C1q should be recommended in all cases with pSLE

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MHC class II deficiency: Report of a novel mutation and special review

The MHC II deficiency is a rare autosomal recessive primary immunodeficiency syndrome with increased susceptibility to respiratory and gastrointestinal infections, failure to thrive and early mortality. This syndrome is caused by mutations in transcription regulators of the MHC II gene and results in development of blind lymphocytes due to the lack of indicatory MHC II molecules. Despite homogeneity of clinical manifestations of patients with MHC II deficiency, the genetic defects underlying this disease are heterogeneous. Herein, we report an Iranian patient with MHC II deficiency harbouring a novel mutation in RFXANK and novel misleading clinical features. He had ataxic gait and dysarthria from 30 months of age. Epidemiology, clinical and immunological features, therapeutic options and prognosis of patients with MHC II are reviewed in this paper

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Exome sequencing revealed C1Q homozygous mutation in Pediatric Systemic Lupus Erythematosus.

INTRODUCTION AND OBJECTIVES: Pediatric Systemic Lupus Erythematosus (pSLE) is an autoimmune disorder of children. Early disease onset raises the probability of genetic etiology and it is more severe than adult SLE. PATIENTS AND METHODS: Herein an eight-year-old girl with pSLE from consanguineous parents is reported. RESULTS: Although she was diagnosed as pSLE since the age of two years, Whole Exome Sequencing (WES) revealed a rare stop-gained C>T mutation in C1QA gene. The variant was validated and segregated in patient and the family. Furthermore, serum levels of the C1q protein were measured and found to be much lower than normal ranges. CONCLUSIONS: This study indicated that C1Q deficiency should be considered as a differential diagnosis of pSLE. Therefore, measurement of C1q should be recommended in all cases with pSLE.

MHC class II deficiency: Report of a novel mutation and special review.

The MHC II deficiency is a rare autosomal recessive primary immunodeficiency syndrome with increased susceptibility to respiratory and gastrointestinal infections, failure to thrive and early mortality. This syndrome is caused by mutations in transcription regulators of the MHC II gene and results in development of blind lymphocytes due to the lack of indicatory MHC II molecules. Despite homogeneity of clinical manifestations of patients with MHC II deficiency, the genetic defects underlying this disease are heterogeneous. Herein, we report an Iranian patient with MHC II deficiency harbouring a novel mutation in RFXANK and novel misleading clinical features. He had ataxic gait and dysarthria from 30 months of age. Epidemiology, clinical and immunological features, therapeutic options and prognosis of patients with MHC II are reviewed in this paper.

Novel AICDA mutation in a case of autosomal recessive hyper-IgM syndrome, growth hormone deficiency and autoimmunity

BACKGROUND: The Hyper-immunoglobulin M syndromes (HIGM) are a heterogeneous group of genetic disorders, which have been rarely reported to be associated with growth hormone deficiency (GHD). METHODS AND RESULTS: A nine-year-old girl with recurrent urinary tract infections, diarrhoea, sinopulmonary infections, and failure to thrive since the age of six months had normal CD3+, CD4+, CD8 + T lymphocytes, and CD19 + B lymphocytes and natural killer (NK) cells, but extremely elevated IgM and significantly decreased IgG and IgA. In view of the patient's short stature, growth hormone evaluation was carried out and growth hormone deficiency established. The patient underwent Ig replacement therapy and received growth hormone therapy in addition to antibiotics and responded well. Furthermore, the patient developed benign cervical lymphadenopathy, as well as elevated erythrocyte sedimentation rate, positive autoantibodies to SSA-Ro, and severely dry eyes, which partially responded to both the punctate occlusion and systemic corticosteroids, at the age of seven years. Sequencing analysis of the exons from activation-induced cytidine deaminase (AICDA) gene revealed that the patient was homozygous for a single T to C transversion at position 455 in exon 4, which replaces a Valine with an Alanine. CONCLUSIONS: To our knowledge, this is a new AICDA mutation, which has not been reported previously in HIGM. The mutation analysis could improve diagnosis of HIGM patients and also elaborating on the spectrum of AICDA mutations

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Investigation of Genetic Defects in Severe Combined Immunodeficiency Patients from Turkey by Targeted Sequencing.

Primary immunodeficiencies (PIDs) represent a large group of disorders with an increased susceptibility to infections. Severe combined immunodeficiency (SCID) is the most severe form of primary immunodeficiencies (PIDs) with marked T-cell lymphopenia. Investigation of the genetic aetiology using classical Sanger sequencing is associated with considerable diagnostic delay. We here established a custom-designed, next-generation sequencing (NGS)-based panel to efficiently identify disease-causing genetic defects in PID patients and applied this method in SCID patients of Turkish origin with previously undefined genetic aetiology. We used HaloPlex enrichment technology, a targeted, NGS-based method which was designed to diagnose patients with SCID and other PIDs. Our HaloPlex panel included a total of 356 PID-related genes, and we searched disease-causing mutations in 19 Turkish SCID patients without a genetic diagnosis. The coverage of targeted regions ranged from 97.47% to 99.62% with an average of 98.31% for all patients. All known SCID genes were covered with a percentage of at least 97.3%. We made a genetic diagnosis in six of 19 (33%) patients, including four novel disease-causing mutations identified in RAG1, JAK3 and IL2RG, respectively. We showed that this NGS-based method can provide rapid genetic diagnosis for patients suffering from SCID, potentially facilitating clinical treatment decisions.

Novel AICDA mutation in a case of autosomal recessive hyper-IgM syndrome, growth hormone deficiency and autoimmunity.

BACKGROUND: The Hyper-immunoglobulin M syndromes (HIGM) are a heterogeneous group of genetic disorders, which have been rarely reported to be associated with growth hormone deficiency (GHD). METHODS AND RESULTS: A nine-year-old girl with recurrent urinary tract infections, diarrhoea, sinopulmonary infections, and failure to thrive since the age of six months had normal CD3+, CD4+, CD8+T lymphocytes, and CD19+B lymphocytes and natural killer (NK) cells, but extremely elevated IgM and significantly decreased IgG and IgA. In view of the patient's short stature, growth hormone evaluation was carried out and growth hormone deficiency established. The patient underwent Ig replacement therapy and received growth hormone therapy in addition to antibiotics and responded well. Furthermore, the patient developed benign cervical lymphadenopathy, as well as elevated erythrocyte sedimentation rate, positive autoantibodies to SSA-Ro, and severely dry eyes, which partially responded to both the punctate occlusion and systemic corticosteroids, at the age of seven years. Sequencing analysis of the exons from activation-induced cytidine deaminase (AICDA) gene revealed that the patient was homozygous for a single T to C transversion at position 455 in exon 4, which replaces a Valine with an Alanine. CONCLUSIONS: To our knowledge, this is a new AICDA mutation, which has not been reported previously in HIGM. The mutation analysis could improve diagnosis of HIGM patients and also elaborating on the spectrum of AICDA mutations.

INFLAMMATORY BOWEL DISEASE-LIKE PHENOTYPE IN A YOUNG GIRL WITH PROLIDASE DEFICIENCY: A NEW SPECTRUM OF CLINICAL MANIFESTATION.

Prolidase deficiency (PD) is an inherited disorder associated with cutaneous ulcers, intellectual disability, unusual facial appearance, skeletal deformities, hematological anomalies, splenomegaly, and chronic infections. We report a girl with PD who presented with early inflammatory bowel disease (IBD). A 2-month-old girl with a dysmorphic face presented with recurrent respiratory tract infections, vomiting, diarrhea and hepatosplenomegaly. She had steatorrhea, abnormal liver enzymes, hypergammaglobulinemia, autoantibody positivity and steatohepatitis in liver biopsy. On follow-up, skin lesions, pruritus and developmental delay were added. At the age of 21 months, IBD was diagnosed with persistent diarrhea, fever, hypoalbuminemia, elevated inflammatory markers, fecal leukocytes and aphthous ulcers in colon. Remission was achieved with prednisone and continued with mesalasine. Thrombocytopenia developed after 3 years. Her findings prompted us to further investigations. PD as the underlying molecular cause of the disease was detected by exome sequencing. In conclusion, PD should be considered in the differential diagnosis of some IBD patients.

Expression levels of FAS are regulated through an evolutionary conserved element in intron 2, which modulates cystic fibrosis disease severity.

We have analyzed frequent naturally occurring variants in the autogene FAS in two independent cystic fibrosis (CF) patient populations. Analysis of FAS expression levels from intestinal epithelial biopsies from 16 unrelated F508del-CFTR homozygotes showed a correlation between FAS intron 2 SNP rs7901656 and signals for Affymetrix GeneChip U133 Plus 2.0 probeset 204781_s_at consistent with a dominant model (P=0.0009). Genotype and haplotype analysis at six informative SNPs spanning the FAS gene locus was carried out on 37 nuclear families representing extreme clinical phenotypes that were selected from the European CF Twin and Sibling Study population of more than 300 affected sibling pairs. Case-control comparison of the haplotype composed of rs2296603-rs7901656-rs1571019 encompassing intron 2 of FAS reached significance (P=0.0246). Comparative phylogenetic analysis and functional annotation of the FAS intron 2 sequence revealed a conserved non-coding sequence surrounding rs7901656 and predicted binding sites for four transcription factors whereby the binding site of c-Rel is altered by rs7901656. Taken together, these findings from two independent CF patient cohorts indicate that allelic variants within FAS intron 2 alter FAS gene expression and that these functional variants modulate the manifestation of CF disease.

Multiple independent second-site mutations in two siblings with somatic mosaicism for Wiskott-Aldrich syndrome.

Wiskott-Aldrich syndrome (WAS) is an X-linked primary immunodeficiency disorder associated with microthrombocytopenia, eczema, autoimmunity and predisposition to malignant lymphoma. Although rare, few cases of somatic mosaicism have been published in WAS patients to date. We here report on two Ukrainian siblings who were referred to us at the age of 3 and 4 years, respectively. Both patients suffered from severe WAS caused by a nonsense mutation in exon 1 of the WAS gene. In both siblings, flow cytometric analysis revealed the presence of Wiskott-Aldrich syndrome protein (WASp)-positive and WASp-negative cell populations among T and B lymphocytes as well as natural killer (NK) cells. In contrast to previously described cases of revertant mosaicism in WAS, molecular analyses in both children showed that the WASp-positive T cells, B cells, and NK cells carried multiple different second-site mutations, resulting in different missense mutations. To our knowledge, this is the first report describing somatic mosaicism in WAS patients caused by several independent second-site mutations in the WAS gene.

Interferon-independent, human immunodeficiency virus type 1 gp120-mediated induction of CXCL10/IP-10 gene expression by astrocytes in vivo and in vitro.

The CXC chemokine gamma interferon (IFN-gamma)-inducible protein CXCL10/IP-10 is markedly elevated in cerebrospinal fluid and brain of individuals infected with human immunodeficiency virus type 1 (HIV-1) and is implicated in the pathogenesis of HIV-associated dementia (HAD). To explore the possible role of CXCL10/IP-10 in HAD, we examined the expression of this and other chemokines in the central nervous system (CNS) of transgenic mice with astrocyte-targeted expression of HIV gp120 under the control of the glial fibrillary acidic protein (GFAP) promoter, a murine model for HIV-1 encephalopathy. Compared with wild-type controls, CNS expression of the CC chemokine gene CCL2/MCP-1 and the CXC chemokine genes CXCL10/IP-10 and CXCL9/Mig was induced in the GFAP-HIV gp120 mice. CXCL10/IP-10 RNA expression was increased most and overlapped the expression of the transgene-encoded HIV gp120 gene. Astrocytes and to a lesser extent microglia were identified as the major cellular sites for CXCL10/IP-10 gene expression. There was no detectable expression of any class of IFN or their responsive genes. In astrocyte cultures, soluble recombinant HIV gp120 protein was capable of directly inducing CXCL10/IP-10 gene expression a process that was independent of STAT1. These findings highlight a novel IFN- and STAT1-independent mechanism for the regulation of CXCL10/IP-10 expression and directly link expression of HIV gp120 to the induction of CXCL10/IP-10 that is found in HIV infection of the CNS. Finally, one function of IP-10 expression may be the recruitment of leukocytes to the CNS, since the brain of GFAP-HIV gp120 mice had increased numbers of CD3(+) T cells that were found in close proximity to sites of CXCL10/IP-10 RNA expression.