Cat Eye Syndrome Research Articles

Prenatal diagnosis of the isodicentric chromosome 22 associated with cat eye syndrome by multiplex ligation-dependent probe amplification

Prenatal diagnosis of the isodicentric chromosome 22 associated with cat eye syndrome by multiplex ligation-dependent probe amplification

GNE-886: A Potent and Selective Inhibitor of the Cat Eye Syndrome Chromosome Region Candidate 2 Bromodomain (CECR2).

The biological function of bromodomains, epigenetic readers of acetylated lysine residues, remains largely unknown. Herein we report our efforts to discover a potent and selective inhibitor of the bromodomain of cat eye syndrome chromosome region candidate 2 (CECR2). Screening of our internal medicinal chemistry collection led to the identification of a pyrrolopyridone chemical lead, and subsequent structure-based drug design led to a potent and selective CECR2 bromodomain inhibitor (GNE-886) suitable for use as an in vitro tool compound.

CECR1-mediated cross talk between macrophages and vascular mural cells promotes neovascularization in malignant glioma

Glioblastomas (glioblastoma multiforme, GBM) are most malignant brain tumors characterized by profound vascularization. The activation of macrophages strongly contributes to tumor angiogenesis during GBM development. Previously, we showed that extracellular adenosine deaminase protein Cat Eye Syndrome Critical Region Protein 1 (CECR1) is highly expressed by M2-like macrophages in GBM where it defines macrophage M2 polarization and contributes to tumor expansion. In this study, the effect of CECR1 in macrophages on tumor angiogenesis was investigated. Immunohistochemical evaluation of GBM tissue samples showed that the expression of CECR1 correlates with microvascular density in the tumors, confirming data from the TCGA set. In a three-dimensional co-culture system consisting of human pericytes, human umbilical vein endothelial cells and THP1-derived macrophages, CECR1 knockdown by siRNA and CECR1 stimulation of macrophages inhibited and promoted new vessel formation, respectively. Loss and gain of function studies demonstrated that PDGFB mRNA and protein levels in macrophages are modulated by CECR1. The proangiogenic properties of CECR1 in macrophages were partially mediated via paracrine activation of pericytes by PDGFB–PDGFRβ signaling. CECR1–PDGFB–PDGFRβ cross-activation between macrophages and pericytes promoted pericyte migration, shown by transwell migration assay, and enhanced expression and deposition of periostin, a matrix component with proangiogenic properties. CECR1 function in (M2-like) macrophages mediates cross talk between macrophages and pericytes in GBM via paracrine PDGFB–PDGFRβ signaling, promoting pericyte recruitment and migration, and tumor angiogenesis. Therefore, CECR1 offers a new portent target for anti-angiogenic therapy in GBM via immune modulation.

Activation of CECR1 in M2-like TAMs promotes paracrine stimulation-mediated glial tumor progression.

The majority of glioma-associated microglia/macrophages have been identified as M2-type macrophages with immune suppressive and tumor supportive action. Recently, the extracellular adenosine deaminase protein Cat Eye Syndrome Critical Region Protein 1 (CECR1) was shown to regulate macrophage maturation. In this study, we investigate the role of CECR1 in the regulation of the glioma-associated macrophage response. Expression of CECR1 was assessed in human glioma samples. CECR1-mediated macrophage response was studied in vitro, using donor derived CD14+ monocytes and the THP-1 monocytic cell line. The response of the human glioma cell line U87 to conditioned medium of macrophages preconditioned with recombinant human CECR1 or CECR1 silencing was also assessed. CECR1 was strongly expressed in high-grade gliomas (P < .001) and correlated positively with the M2 phenotype markers in tumor-associated microglia/macrophages (TAMs) (overall, P < .05). In vitro studies confirmed the presence of a significantly higher level of CECR1 expression in M2-like macrophages exposed to U87 conditioned medium (P < .001). CECR1 knockdown or stimulation of macrophages affected differentiation toward the M2-like phenotype. Stimulation of U87 cells with conditioned medium of CECR1 knockdown or stimulated macrophages affected tumor cell proliferation and migration, coinciding with altered intracellular signaling of mitogen-activated protein kinase (MAPK). In glioma tissue samples, CECR1 expression correlated with Ki67 and MAPK signaling protein. CECR1 is a potent regulator of TAM polarization and is consistently highly expressed by M2-type TAMs, particularly in high-grade glioma. Paracrine effects induced by CECR1 in M2-like TAMs activate MAPK signaling and stimulate the proliferation and migration of glioma cells.

Drug resistant epilepsy in a young male with Cat Eye Syndrome: a case study

Drug resistant epilepsy in a young male with Cat Eye Syndrome: a case study

Mycobacterium tuberculosis ESAT6 and CPF10 Induce Adenosine Deaminase 2 mRNA Expression in Monocyte-Derived Macrophages.

BackgroundDelayed hypersensitivity plays a large role in the pathogenesis of tuberculous pleural effusion (TPE). Macrophages infected with live Mycobacterium tuberculosis (MTB) increase the levels of adenosine deaminase2 (ADA2) in the pleural fluid of TPE patients. However, it is as yet unclear whether ADA2 can be produced by macrophages when challenged with MTB antigens alone. This study therefore evaluated the levels of ADA2 mRNA expression, using monocyte-derived macrophages (MDMs) stimulated with MTB antigens.MethodsPurified monocytes from the peripheral blood mononuclear cells of healthy volunteers were differentiated into macrophages using granulocyte-macrophage colony-stimulating factor (GM-CSF) or macrophage colony-stimulating factor (M-CSF). The MDMs were stimulated with early secretory antigenic target protein 6 (ESAT6) and culture filtrate protein 10 (CFP10). The mRNA expression levels for the cat eye syndrome chromosome region, candidate 1 (CECR1) gene encoding ADA2 were then measured.ResultsCECR1 mRNA expression levels were significantly higher in MDMs stimulated with ESAT6 and CFP10, than in the unstimulated MDMs. When stimulated with ESAT6, M-CSF-treated MDMs showed more pronounced CECR1 mRNA expression than GM-CSF-treated MDMs. Interferon-γ decreased the ESAT6- and CFP10-induced CECR1 mRNA expression in MDMs. CECR1 mRNA expression levels were positively correlated with mRNA expression of tumor necrosis factor α and interleukin 10, respectively.ConclusionADA2 mRNA expression increased when MDMs were stimulated with MTB antigens alone. This partly indicates that pleural fluid ADA levels could increase in patients with culture-negative TPE. Our results may be helpful in improving the understanding of TPE pathogenesis.

Monogenic polyarteritis: the lesson of ADA2 deficiency

The deficiency of Adenosine Deaminase 2 (DADA2) is a new autoinflammatory disease characterised by an early onset vasculopathy with livedoid skin rash associated with systemic manifestations, CNS involvement and mild immunodeficiency.This condition is secondary to autosomal recessive mutations of CECR1 (Cat Eye Syndrome Chromosome Region 1) gene, mapped to chromosome 22q11.1, that encodes for the enzymatic protein adenosine deaminase 2 (ADA2). By now 19 different mutations in CECR1 gene have been detected.The pathogenetic mechanism of DADA2 is still unclear. ADA2 in a secreted protein mainly expressed by cells of the myeloid lineage; its enzymatic activity is higher in conditions of hypoxia, inflammation and oncogenesis. Moreover ADA2 is able to induce macrophages proliferation and differentiation; it’s deficiency is in fact associated with a reduction of anti-inflammatory macrophages (M2). The deficiency of ADA2 is also associated with an up-regulation of neutrophils-expressed genes and an increased secretion of pro-inflammatory cytokines. The mild immunodeficiency detected in many DADA2 patients suggests a role of this protein in the adaptive immune response; an increased mortality of B cells and a reduction in the number of memory B cells, terminally differentiated B cells and plasmacells has been described in many patients. The lack of the protein is associated with endothelium damage; however the function of this protein in the endothelial homeostasis is still unknown.From the clinical point of view, this disease is characterized by a wide spectrum of severity. Chronic or recurrent systemic inflammation with fever, elevation of acute phase reactants and skin manifestations (mainly represented by livedo reticularis) is the typical clinical picture. While in some patients the disease is mild and skin-limited, others present a severe, even lethal, disease with multi-organ involvement; the CNS involvement is rather common with ischemic or hemorrhagic strokes. In many patients not only the clinical picture but also the histopathologic features are undistinguishable from those of systemic polyarteritis nodosa (PAN). Of note, patients with an unusual phenotype, mainly dominated by clinical manifestations suggestive for an immune-disrective condition, have been described.Due to its rarity, the response to treatment of DADA2 is still anecdotal. While steroids can control the disease’s manifestations at high dosage, none of the common immunosuppressive drugs turned out to be effective. Biologic drugs have been used only in few patients, without a clear effectiveness; anti-TNF drugs are those associated to a better clinical response. Hematopoietic stem cells transplantation was effective in patients with a severe phenotype.

Adenosine Deaminase 2 Deficiency As a Cause of Pure Red Cell Aplasia Mimicking Diamond Blackfan Anemia

Diamond Blackfan anemia (DBA) is an inherited pure red cell aplasia. Most cases present in the first year of life with elevation in erythrocyte adenosine deaminase (eADA) and frequently with increased mean corpuscular volume (MCV) and hemoglobin F (hgb F). Approximately 70 percent of cases are due to a mutation in one of several ribosomal protein (RP) genes or in GATA1, whereas the remaining cases are genetically uncharacterized. Here we report a child born with severe anemia and diagnosed with DBA at 2 months of age. His bone marrow was normocellular with a paucity of erythroid progenitors and scattered lymphocytes. An eADA level was not obtained prior to the first red cell transfusion. He was red cell transfusion dependent and his anemia did not respond to a steroid trial. His 4 year old sister, who had normal hemoglobin, MCV, hgb F, and eADA measurements, served as his HLA identical donor for hematopoietic stem cell transplantation (HSCT). HSCT resulted in 100% donor chimerism, but red cell engraftment was not achieved. He subsequently underwent a mismatched unrelated HSCT with trilineage engraftment.Ten years later, at the age of 14 years, the sister presented with profound hypoproductive normocytic anemia. The bone marrow showed absence of erythroid precursors and presence of lymphoid aggregates. Findings of immunodeficiency included numerous cutaneous warts, recurrent aphthous ulcers, Epstein Barr virus (EBV) reactivation, low IgM, and low numbers and percentages of CD19+ and CD3-56+16+ lymphocytes. The anemia and reticulocytopenia persisted despite resolution of EBV reactivation. Upon her presentation, levels of iron, ferritin, transferrin saturation, and liver transaminases were elevated. A liver biopsy obtained after transfusion of a total of 60 ml/kg packed red blood cells demonstrated 4.8 mg Fe/g dry liver weight with stage 2 portal fibrosis.Targeted DNA sequencing studies performed on the affected sister were negative for single nucleotide variants in any of 12 RP genes previously implicated in DBA and a genome wide chromosome microarray was normal. Whole exome analysis of her and her parents demonstrated that she carried compound heterozygous variants in CECR1 (cat eye syndrome chromosome region, candidate 1). The variant p.R169Q had been previously reported as pathogenic, while the p.G358R variant was of uncertain significance. These variants are present at frequencies of 4.9X10-4 and 2.6X10-5 in the Exome Aggregation Consortium database, respectively. Analysis of buccal swab DNA of the proband showed the same biallelic variants. An unaffected 16-year-old sibling had a normal genotype. CECR1 encodes adenosine deaminase 2 (ADA2) and ADA2 levels in the plasma of the affected sister were markedly low, consistent with a deficiency state.CECR1 is highly expressed in cells of myeloid origin and ADA2 is a secreted protein implicated in macrophage differentiation and proliferation. Deficiency of ADA2 (DADA2) results in aberrant monocyte differentiation favoring M1 over M2 macrophages, thereby resulting in a proinflammatory state. Recent descriptions of patients with DADA2 due to CECR1 mutations reported a spectrum of phenotypes including intermittent fevers, lacunar stroke in childhood, livedoid rash, polyarteritis nodosa, and immunodeficiency with B lymphopenia and low IgM levels. Our cases are similar to the report of one of two brothers, homozygous for CECR1 p.R169Q, described by van Montfrans, et al,. (NEJM, 2014). The eldest was given a diagnosis of atypical DBA (refractory pure red cell aplasia) in infancy and underwent a HSCT from his asymptomatic, HLA identical brother. This HSCT resulted in non-engraftment, necessitating a subsequent unrelated donor HSCT. The younger sibling donor later developed hepatosplenomegaly, profound lymphopenia, and evidence of an inflammatory state.Together, these three cases support pure red cell aplasia as a presentation of DADA2 and that this may be confused with DBA, particularly when manifest in infancy. We propose DADA2 should be considered in patients with genetically uncharacterized DBA. Differentiating features to suggest DADA2 may include normal eADA, MCV, and hgb F levels and findings of associated immunodeficiency. Additionally, the macrophage activation due to DADA2 may have played a role in the iron overload observed in our second patient prior to any red cell transfusion. DisclosuresNo relevant conflicts of interest to declare.

Analysis of chromosome 22q11 copy number variations by multiplex ligation-dependent probe amplification for prenatal diagnosis of congenital heart defect.

BackgroundCongenital heart defects (CHD) represent one of the most common birth defects. This study aimed to evaluate the value of multiplex ligation-dependent probe amplification (MLPA) as a tool to detect the copy number variations (CNVs) of 22q11 in fetuses with CHD.ResultsA large cohort of 225 fetuses with CHD was screened by fetal echocardiography. Once common chromosome abnormalities in 30 fetuses were screened out by conventional G-banding analysis, the CNVs of chromosome 22q11 in the remaining 195 fetuses were determined by MLPA for prenatal genetic counseling. In 195 CHD fetuses with normal karyotype, 11 cases had pathological CNVs, including 22q11.2 deletion (seven cases), the deletion of 22q11 cat eye syndrome (CES) region (one case), 22q11.2 duplication (one case), 22q13.3 deletion (one case) and 17p13.3 deletion (one case). In total, our findings from MLPA screening represented 4.9 % in our cohort. Among these, three cases were inherited CNVs, and eight cases were de novo. These CNVs were further verified by single nucleotide polymorphism (SNP)-array analysis, and their chromosomal location was refined.ConclusionThis study indicated that MLPA could serve as an effective test for routine prenatal diagnosis of 22q11 in fetuses with CHD.

Growth hormone deficiency and pituitary malformation in a recurrent Cat-Eye syndrome: A family report

Growth hormone deficiency affects roughly between one in 3000 and one in 4000 children with most instances of growth hormone deficiency being idiopathic. Growth hormone deficiency can also be associated with genetic diseases or chromosome abnormalities. Association of growth hormone deficiency together with hypothalamic–pituitary axis malformation and Cat-Eye syndrome is a very rare condition. We report a family with two brothers presenting with growth delay due to a growth hormone deficiency associated with a polymalformation syndrome. They both displayed pre-auricular pits and tags, imperforate anus and Duane retraction syndrome. Both parents and a third unaffected son displayed normal growth pattern. Cerebral MRI showed a hypothalamic–pituitary axis malformation in the two affected brothers. Cytogenetic studies revealed a type I small supernumerary marker chromosome derived from chromosome 22 resulting in a tetrasomy 22pter-22q11.21 characteristic of the Cat-Eye syndrome. The small supernumerary marker chromosome was present in the two affected sons and the mother in a mosaic state. Patients with short stature due to growth hormone deficiency should be evaluated for chromosomal abnormality. Family study should not be underestimated.

Monogenic polyarteritis nodosa caused by ADA2 Deficiency: the GOSH experience

Recessive mutations in Cat Eye syndrome Critical Region 1 (CECR1), the gene encoding adenosine deaminase 2 (ADA2) have been recently reported to cause polyarteritis nodosa (PAN) with highly varied clinical expression.

AB024. Chromosome microarray analysis (CMA) for the diagnosis of children with developmental delay and multiple congenital anomalies in Singapore.

Chromosome microarray analysis (CMA) is a sensitive method to identify submicroscopic changes too small to be detected by conventional karyotyping. Due to its high-sensitivity in identifying regions with structural variation and hence the genes involved, it is recommended to be the first-tier genetic test for children with intellectual disabilities, development delay or multiple congenital anomalies, and is routinely available in USA and many countries in Europe. Our lab has started offering this as a clinical test based on the research experience on screening >400 children with developmental delay and multiple congenital anomalies since February 2014. To date, 271 patients have been screened using the Agilent 4×180K CGH + SNP array. Copy number variants (CNVs) ranging in size from 10 kb to 154 Mb were found in 109 patients (40%). Pathogenic and likely pathogenic CNVs were found in 55 (20%). These included 45 with deletions, 8 with duplications and 2 patients with both deletion and duplication. Recurrent microdeletion and microduplication syndromes including the Angelman/Prader-Willi syndrome [5], 1p36 microdeletion [3], Williams syndrome [2], 22q11.2 distal deletion syndrome [2], 16p13.3 microdeletion syndrome [2], Cat Eye syndrome, Cri du Chat syndrome, Miller Decker syndrome, 3q29 microdeletion, 15q24 microdeletion, and 1q43q44 syndrome were among the variants detected in our patients. CNVs of uncertain clinical significance were detected in 54 (20%) individuals: 32 were duplications, 18 were deletions and one with both deletion and duplication. However, due to the high cost of the test, parental testing was not performed and hence, significance of these variants could not be established conclusively. In conclusion, CMA is a powerful tool in identifying pathogenic chromosomal copy number alternations. However, due to the high cost of the test, parental testing for the cases where variants of uncertain significant are found is often not possible. CMA is useful in identifying pathogenic structural rearrangement. More data are necessary to be collected to enhance interpretation of the results.

Cat eye syndrome

Cat eye syndrome

Type B Interrupted Aortic Arch and Hydrocephalus Associated with Mosaicism of a 1.37 Mb Amplified Cat Eye Syndrome Critical Region

Type B Interrupted Aortic Arch and Hydrocephalus Associated with Mosaicism of a 1.37 Mb Amplified Cat Eye Syndrome Critical Region

Severe psychomotor delay in a severe presentation of cat-eye syndrome.

Cat-eye syndrome is a rare genetic syndrome of chromosomal origin. Individuals with cat-eye syndrome are characterized by the presence of preauricular pits and/or tags, anal atresia, and iris coloboma. Many reported cases also presented with variable congenital anomalies and intellectual disability. Most patients diagnosed with CES carry a small supernumerary bisatellited marker chromosome, resulting in partial tetrasomy of 22p-22q11.21. There are two types of small supernumerary marker chromosome, depending on the breakpoint site. In a very small proportion of cases, other cytogenetic anomalies are reportedly associated with the cat-eye syndrome phenotype. Here, we report a patient with cat-eye syndrome caused by a type 1 small supernumerary marker chromosome. The phenotype was atypical and included a severe developmental delay. The use of array comparative genomic hybridization ruled out the involvement of another chromosomal imbalance in the neurological phenotype. In the literature, only a few patients with cat-eye syndrome present with a severe developmental delay, and all of the latter carried an atypical partial trisomy 22 or an uncharacterized small supernumerary marker chromosome. Hence, this is the first report of a severe neurological phenotype in cat-eye syndrome with a typical type 1 small supernumerary marker chromosome. Our observation clearly complicates prognostic assessment, particularly when cat-eye syndrome is diagnosed prenatally.

Small supernumerary marker chromosomes and their correlation with specific syndromes.

A small supernumerary marker chromosome (sSMC) is a structurally abnormal chromosome. It is an additional chromosome smaller than one chromosome most often lacking a distinct banding pattern and is rarely identifiable by conventional banding cytogenetic analysis. The origin and composition of an sSMC is recognizable by molecular cytogenetic analysis. These sSMCs are seen in different shapes, including the ring, centric minute, and inverted duplication shapes. The effects of sSMCs on the phenotype depend on factors such as size, genetic content, and the level of the mosaicism. The presence of an sSMC causes partial tris- or tetrasomy, and 70% of the sSMC carriers are clinically normal, while 30% are abnormal in some way. In 70% of the cases the sSMC is de novo, in 20% it is inherited from the mother, and in 10% it is inherited from the father. An sSMC can be causative for specific syndromes such as Emanuel, Pallister-Killian, or cat eye syndromes. There may be more specific sSMC-related syndromes, which may be identified by further investigation. These 10 syndromes can be useful for genetic counseling after further study.

When less is more: primary immunodeficiency with an autoinflammatory kick.

Purpose of reviewNext-generation sequencing is revolutionizing the molecular taxonomy of human disease. Recent studies of patients with unexplained autoinflammatory disorders reveal germline genetic mutations that target important regulators of innate immunity.Recent findingsWhole-exome analyses of previously undiagnosed patients have catalyzed the recognition of two new disease genes. First, a phenotypic spectrum, including livedo racemosa, fever with early-onset stroke, polyarteritis nodosa, and Sneddon syndrome, is caused by loss-of-function mutations in cat eye syndrome chromosome region, candidate 1 (CECR1), encoding adenosine deaminase 2. Adenosine deaminase 2 is a secreted protein expressed primarily in myeloid cells, and a regulator of macrophage differentiation and endothelial development. Disease-associated mutations impair anti-inflammatory M2 macrophage differentiation. Second, patients presenting with cold-induced urticaria, granulomatous rash, autoantibodies, and common variable immunodeficiency, or with blistering skin lesions, bronchiolitis, enterocolitis, ocular inflammation, and mild immunodeficiency harbor distinct mutations in phospholipase Cγ2, encoding a signaling molecule expressed in natural killer cells, mast cells, and B lymphocytes. These mutations inhibit the function of a phospholipase Cγ2 autoinhibitory domain, causing increased or constitutive signaling.SummaryThese findings underscore the power of next-generation sequencing, demonstrating how the primary deficiency of key molecular regulators or even regulatory motifs may lead to autoinflammation, and suggesting a possible role for cat eye syndrome chromosome region, candidate 1 and phospholipase Cγ2 in common diseases.

Early-Onset Stroke and Vasculopathy Associated with Mutations in ADA2

BackgroundWe observed a syndrome of intermittent fevers, early-onset lacunar strokes and other neurovascular manifestations, livedoid rash, hepatosplenomegaly, and systemic vasculopathy in three unrelated patients. We suspected a genetic cause because the disorder presented in early childhood.MethodsWe performed whole-exome sequencing in the initial three patients and their unaffected parents and candidate-gene sequencing in three patients with a similar phenotype, as well as two young siblings with polyarteritis nodosa and one patient with small-vessel vasculitis. Enzyme assays, immunoblotting, immunohistochemical testing, flow cytometry, and cytokine profiling were performed on samples from the patients. To study protein function, we used morpholino-mediated knockdowns in zebrafish and short hairpin RNA knockdowns in U937 cells cultured with human dermal endothelial cells.ResultsAll nine patients carried recessively inherited mutations in CECR1 (cat eye syndrome chromosome region, candidate 1), encoding adenosine deaminase 2 (ADA2), that were predicted to be deleterious; these mutations were rare or absent in healthy controls. Six patients were compound heterozygous for eight CECR1 mutations, whereas the three patients with polyarteritis nodosa or small-vessel vasculitis were homozygous for the p.Gly47Arg mutation. Patients had a marked reduction in the levels of ADA2 and ADA2-specific enzyme activity in the blood. Skin, liver, and brain biopsies revealed vasculopathic changes characterized by compromised endothelial integrity, endothelial cellular activation, and inflammation. Knockdown of a zebrafish ADA2 homologue caused intracranial hemorrhages and neutropenia — phenotypes that were prevented by coinjection with nonmutated (but not with mutated) human CECR1. Monocytes from patients induced damage in cocultured endothelial-cell layers.ConclusionsLoss-of-function mutations in CECR1 were associated with a spectrum of vascular and inflammatory phenotypes, ranging from early-onset recurrent stroke to systemic vasculopathy or vasculitis. (Funded by the National Institutes of Health Intramural Research Programs and others.)

Cat eye syndrome, anorectal malformation, and Hirschsprung's disease.

Cat eye syndrome, anorectal malformation, and Hirschsprung's disease.

A severe prenatal presentation of Cat Eye Syndrome

Institut deGe´ne´tique Me´dicale, Hoˆpital Jeanne de Flandre, CHRU de Lille, Lille, FranceCorrespondence to Guillaume Jedraszak, MD, Laboratoire de Ge´ne´tiqueMole´culaire Me´dicale, CHU d’Amiens, Avenue R. Laennec, 80054 AmiensCedex 1, FranceTel: +33 3 22 08 71 10; fax: +33 3 22 08 71 09;e-mail: guillaumejedraszak@yahoo.frReceived 2 May 2013 Accepted 8 August 2013