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Cytokinetic membrane abscission is a spatially and temporally regulated process that requires ESCRT (endosomal sorting complexes required for transport)dependent control of membrane remodeling at the midbody, a subcellular organelle that defines the cleavage site. Alteration of ESCRT function can lead to cataract, but the underlying mechanism and its relation to cytokinesis are unclear. We found a lens-specific cytokinetic process that required PI3K-C2α (phosphatidylinositol-4-phosphate 3-kinase catalytic subunit type 2α), its lipid product PI(3,4)P2 (phosphatidylinositol 3,4-bisphosphate), and the PI(3,4)P2binding ESCRT-II subunit VPS36 (vacuolar protein-sorting-associated protein 36). Loss of each of these components led to impaired cytokinesis, triggering premature senescence in the lens of fish, mice, and humans. Thus, an evolutionarily conserved pathway underlies the cell typespecific control of cytokinesis that helps to prevent early onset cataract by protecting from senescence.
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Catarata/patología , Senescencia Celular , Citocinesis , Complejos de Clasificación Endosomal Requeridos para el Transporte/metabolismo , Cristalino/citología , Fosfatidilinositol 3-Quinasas/metabolismo , Fosfatidilinositoles/metabolismo , Envejecimiento Prematuro , Animales , Evolución Biológica , Proteínas de Unión al Calcio/metabolismo , Catarata/metabolismo , Proteínas de Ciclo Celular/metabolismo , Línea Celular , Humanos , Cristalino/crecimiento & desarrollo , Cristalino/metabolismo , Ratones , Mutación , Fosfatidilinositol 3-Quinasas/genética , Fosfatidilinositol 4,5-Difosfato/metabolismo , Tubulina (Proteína)/metabolismo , Pez Cebra , Proteínas de Pez Cebra/genética , Proteínas de Pez Cebra/metabolismoRESUMEN
PURPOSE: Constitutional mismatch repair deficiency syndrome (CMMRD) is a lethal cancer predisposition syndrome characterized by early-onset synchronous and metachronous multiorgan tumors. We designed a surveillance protocol for early tumor detection in these individuals. PATIENTS AND METHODS: Data were collected from patients with confirmed CMMRD who were registered in the International Replication Repair Deficiency Consortium. Tumor spectrum, efficacy of the surveillance protocol, and malignant transformation of low-grade lesions were examined for the entire cohort. Survival outcomes were analyzed for patients followed prospectively from the time of surveillance implementation. RESULTS: A total of 193 malignant tumors in 110 patients were identified. Median age of first cancer diagnosis was 9.2 years (range: 1.7-39.5 years). For patients undergoing surveillance, all GI and other solid tumors, and 75% of brain cancers were detected asymptomatically. By contrast, only 16% of hematologic malignancies were detected asymptomatically (P < .001). Eighty-nine patients were followed prospectively and used for survival analysis. Five-year overall survival (OS) was 90% (95% CI, 78.6 to 100) and 50% (95% CI, 39.2 to 63.7) when cancer was detected asymptomatically and symptomatically, respectively (P = .001). Patient outcome measured by adherence to the surveillance protocol revealed 4-year OS of 79% (95% CI, 54.8 to 90.9) for patients undergoing full surveillance, 55% (95% CI, 28.5 to 74.5) for partial surveillance, and 15% (95% CI, 5.2 to 28.8) for those not under surveillance (P < .0001). Of the 64 low-grade tumors detected, the cumulative likelihood of transformation from low-to high-grade was 81% for GI cancers within 8 years and 100% for gliomas in 6 years. CONCLUSION: Surveillance and early cancer detection are associated with improved OS for individuals with CMMRD.
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Neoplasias Encefálicas/mortalidad , Neoplasias Colorrectales/mortalidad , Reparación de la Incompatibilidad de ADN , Enzimas Reparadoras del ADN/deficiencia , Detección Precoz del Cáncer/métodos , Síndromes Neoplásicos Hereditarios/mortalidad , Adolescente , Adulto , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/epidemiología , Neoplasias Encefálicas/metabolismo , Niño , Preescolar , Neoplasias Colorrectales/diagnóstico , Neoplasias Colorrectales/epidemiología , Neoplasias Colorrectales/metabolismo , Femenino , Estudios de Seguimiento , Humanos , Masculino , Síndromes Neoplásicos Hereditarios/diagnóstico , Síndromes Neoplásicos Hereditarios/epidemiología , Síndromes Neoplásicos Hereditarios/metabolismo , Vigilancia de la Población , Pronóstico , Estudios Prospectivos , Tasa de Supervivencia , Estados Unidos/epidemiología , Adulto JovenRESUMEN
Majewski Osteodysplastic Primordial Dwarfism type II (MOPDII) is a form of dwarfism associated with severe microcephaly, characteristic skeletal findings, distinct dysmorphic features and increased risk for cerebral infarctions. The condition is caused by bi-allelic loss-of-function variants in the gene PCNT. Here we describe the identification of a novel founder pathogenic variant c.3465-1Gâ¯>â¯A observed in carriers from multiple Druze villages in Northern Israel. RNA studies show that the variant results in activation of a cryptic splice site causing a coding frameshift. The study was triggered by the diagnosis of a single child with MOPDII and emphasizes the advantages of applying next generation sequencing technologies in community genetics and the importance of establishing population-specific sequencing databases.
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Antígenos/genética , Efecto Fundador , Estudios de Asociación Genética , Predisposición Genética a la Enfermedad , Mutación , Adolescente , Alelos , Línea Celular Tumoral , Análisis Mutacional de ADN , Enanismo/diagnóstico , Enanismo/genética , Facies , Femenino , Retardo del Crecimiento Fetal/diagnóstico , Retardo del Crecimiento Fetal/genética , Estudios de Asociación Genética/métodos , Pruebas Genéticas , Humanos , Israel , Masculino , Microcefalia/diagnóstico , Microcefalia/genética , Osteocondrodisplasias/diagnóstico , Osteocondrodisplasias/genética , Linaje , Fenotipo , Secuenciación del ExomaRESUMEN
PIK3C2A is a class II member of the phosphoinositide 3-kinase (PI3K) family that catalyzes the phosphorylation of phosphatidylinositol (PI) into PI(3)P and the phosphorylation of PI(4)P into PI(3,4)P2. At the cellular level, PIK3C2A is critical for the formation of cilia and for receptor mediated endocytosis, among other biological functions. We identified homozygous loss-of-function mutations in PIK3C2A in children from three independent consanguineous families with short stature, coarse facial features, cataracts with secondary glaucoma, multiple skeletal abnormalities, neurological manifestations, among other findings. Cellular studies of patient-derived fibroblasts found that they lacked PIK3C2A protein, had impaired cilia formation and function, and demonstrated reduced proliferative capacity. Collectively, the genetic and molecular data implicate mutations in PIK3C2A in a new Mendelian disorder of PI metabolism, thereby shedding light on the critical role of a class II PI3K in growth, vision, skeletal formation and neurological development. In particular, the considerable phenotypic overlap, yet distinct features, between this syndrome and Lowe's syndrome, which is caused by mutations in the PI-5-phosphatase OCRL, highlight the key role of PI metabolizing enzymes in specific developmental processes and demonstrate the unique non-redundant functions of each enzyme. This discovery expands what is known about disorders of PI metabolism and helps unravel the role of PIK3C2A and class II PI3Ks in health and disease.
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Enfermedades del Desarrollo Óseo/genética , Catarata/genética , Trastornos de la Motilidad Ciliar/genética , Enanismo/genética , Mutación , Fosfatidilinositol 3-Quinasas/genética , Adolescente , Adulto , Niño , Consanguinidad , Femenino , Fibroblastos/metabolismo , Humanos , Masculino , Linaje , Fenotipo , Adulto JovenAsunto(s)
Inhibidores Enzimáticos/uso terapéutico , Enfermedad de Gaucher/tratamiento farmacológico , Pirrolidinas/uso terapéutico , Inhibidores Enzimáticos/administración & dosificación , Inhibidores Enzimáticos/efectos adversos , Enfermedad de Gaucher/diagnóstico , Humanos , Pirrolidinas/administración & dosificación , Pirrolidinas/efectos adversos , Resultado del TratamientoRESUMEN
Mitochondrial protein synthesis requires charging mt-tRNAs with their cognate amino acids by mitochondrial aminoacyl-tRNA synthetases, with the exception of glutaminyl mt-tRNA (mt-tRNAGln). mt-tRNAGln is indirectly charged by a transamidation reaction involving the GatCAB aminoacyl-tRNA amidotransferase complex. Defects involving the mitochondrial protein synthesis machinery cause a broad spectrum of disorders, with often fatal outcome. Here, we describe nine patients from five families with genetic defects in a GatCAB complex subunit, including QRSL1, GATB, and GATC, each showing a lethal metabolic cardiomyopathy syndrome. Functional studies reveal combined respiratory chain enzyme deficiencies and mitochondrial dysfunction. Aminoacylation of mt-tRNAGln and mitochondrial protein translation are deficient in patients' fibroblasts cultured in the absence of glutamine but restore in high glutamine. Lentiviral rescue experiments and modeling in S. cerevisiae homologs confirm pathogenicity. Our study completes a decade of investigations on mitochondrial aminoacylation disorders, starting with DARS2 and ending with the GatCAB complex.
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Cardiomiopatías/enzimología , Cardiomiopatías/genética , Enfermedades Mitocondriales/enzimología , Enfermedades Mitocondriales/genética , Mutación/genética , Transferasas de Grupos Nitrogenados/genética , Subunidades de Proteína/genética , Secuencia de Aminoácidos , Femenino , Fibroblastos/metabolismo , Fibroblastos/patología , Humanos , Lactante , Recién Nacido , Lentivirus/metabolismo , Masculino , Modelos Moleculares , Miocardio/patología , Miocardio/ultraestructura , Transferasas de Grupos Nitrogenados/química , Transferasas de Grupos Nitrogenados/metabolismo , Fosforilación Oxidativa , Linaje , Biosíntesis de Proteínas , Subunidades de Proteína/química , Subunidades de Proteína/metabolismo , ARN de Transferencia/metabolismo , Saccharomyces cerevisiae/metabolismoRESUMEN
OBJECTIVE: The growing availability of next-generation sequencing technologies has revolutionized medical genetics, facilitating discovery of causative genes in numerous Mendelian disorders. Nevertheless, there are still many undiagnosed cases. We report the experience of the Genetics Institute at Rambam Health Care Campus in rare disease diagnostics using whole-exome sequencing (WES). METHODS: Phenotypic characterization of patients was done in close collaboration with referring physicians. We utilized WES analysis for diagnosing families suspected for rare genetic disorders. Bioinformatic analysis was performed in-house using the Genoox analysis platform. RESULTS: Between the years 2014 and 2017, we studied 34 families. Neurological manifestations were the most common reason for referral (38%), and 55% of families were consanguineous. A definite diagnosis was reached in 21 cases (62%). Four cases (19%) were diagnosed with variants in novel genes. In addition, six families (18%) had strong candidate novel gene discoveries still under investigation. Therefore, the true diagnosis rate is probably even higher. Some of the diagnoses had a significant impact such as alerting the patient management and providing a tailored treatment. CONCLUSIONS: An accurate molecular diagnosis can set the stage for improved patient care and provides an opportunity to study disease mechanisms, which may lead to development of tailored treatments. Data from our genetic research program demonstrate high diagnostic and novel disease-associated or causative gene discovery rates. This is likely related to the unique genetic architecture of the population in Northern Israel as well as to our strategy for case selection and the close collaboration between analysts, geneticists, and clinicians, all working in the same hospital.
RESUMEN
Immunoglobulin class-switch recombination (CSR) and somatic hypermutations (SHMs) are prerequisites for antibody and immunoglobulin receptor maturation and adaptive immune diversity. The mismatch repair (MMR) machinery, consisting of homologs of MutSα, MutLα, and MutSß (MSH2/MSH6, MLH1/PMS2, and MSH2/MSH3, respectively) and other proteins, is involved in CSR, primarily acting as a backup for nonhomologous end-joining repair of activation-induced cytidine deaminase-induced DNA mismatches and, furthermore, in addition to error-prone polymerases, in the repair of SHM-induced DNA breaks. A varying degree of antibody formation defect, from IgA or selective IgG subclass deficiency to common variable immunodeficiency and hyper-IgM syndrome, has been detected in a small number of patients with constitutional mismatch repair deficiency (CMMRD) due to biallelic loss-of-function mutations in one of the MMR genes (PMS2, MSH6, MLH1, or MSH2). To elucidate the clinical relevance of a presumed primary immunodeficiency (PID) in CMMRD, we systematically collected clinical history and laboratory data of a cohort of 15 consecutive, unrelated patients (10 not previously reported) with homozygous/compound heterozygous mutations in PMS2 (n = 8), MSH6 (n = 5), and MLH1 (n = 2), most of whom manifested with typical malignancies during childhood. Detailed descriptions of their genotypes, phenotypes, and family histories are provided. Importantly, none of the patients showed any clinical warning signs of PID (infections, immune dysregulation, inflammation, failure to thrive, etc.). Furthermore, we could not detect uniform or specific patterns of laboratory abnormalities. The concentration of IgM was increased in 3 out of 12, reduced in 3 out of 12, and normal in 6 out of 12 patients, while concentrations of IgG and IgG subclasses, except IgG4, and of IgA, and specific antibody formation were normal in most. Class-switched B memory cells were reduced in 5 out of 12 patients, and in 9 out of 12 also the CD38hiIgM- plasmablasts were reduced. Furthermore, results of next generation sequencing-based analyses of antigen-selected B-cell receptor rearrangements showed a significantly reduced frequency of SHM and an increased number of rearranged immunoglobulin heavy chain (IGH) transcripts that use IGHG3, IGHG1, and IGHA1 subclasses. T cell subsets and receptor repertoires were unaffected. Together, neither clinical nor routine immunological laboratory parameters were consistently suggestive of PID in these CMMRD patients, but previously shown abnormalities in SHM and rearranged heavy chain transcripts were confirmed.
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BACKGROUND: Intestinal integrity is essential for proper nutrient absorption and tissue homeostasis, with damage leading to enteric protein loss, that is, protein-losing enteropathy (PLE). Recently, homozygous nonsense variants in the plasmalemma vesicle-associated protein gene (PLVAP) were reported in two patients with severe congenital PLE. PLVAP is the building block of endothelial cell (EC) fenestral diaphragms; its importance in barrier function is supported by mouse models of Plvap deficiency. OBJECTIVE: To genetically diagnose two first-degree cousins once removed, who presented with PLE at ages 22 and 2.5 years. METHODS: Family-based whole exome sequencing was performed based on an autosomal recessive inheritance model. In silico analyses were used to predict variant impact on protein structure and function. RESULTS: We identified a rare homozygous variant (NM_031310.2:c.101T>C;p.Leu34Pro) in PLVAP, which co-segregated with the disease. Leu34 is predicted to be located in a highly conserved, hydrophobic, α-helical region within the protein's transmembrane domain, suggesting Leu34Pro is likely to disrupt protein function and/or structure. Electron microscopy and PLVAP immunohistochemistry demonstrated apparently normal diaphragm morphology, predicted to be functionally affected. CONCLUSIONS: Biallelic missense variants in PLVAP can cause an attenuated form of the PLE and hypertriglyceridaemia syndrome. Our findings support the role of PLVAP in the pathophysiology of PLE, expand the phenotypic and mutation spectrums and underscore PLVAP's importance in EC barrier function in the gut.
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Proteínas Portadoras/genética , Estudios de Asociación Genética , Homocigoto , Proteínas de la Membrana/genética , Mutación Missense , Fenotipo , Enteropatías Perdedoras de Proteínas/diagnóstico , Enteropatías Perdedoras de Proteínas/genética , Adulto , Sustitución de Aminoácidos , Biomarcadores , Biopsia , Proteínas Portadoras/química , Biología Computacional/métodos , Consanguinidad , Femenino , Humanos , Recién Nacido , Masculino , Proteínas de la Membrana/química , Modelos Moleculares , Linaje , Conformación Proteica , Enteropatías Perdedoras de Proteínas/metabolismo , Relación Estructura-Actividad , Adulto JovenRESUMEN
INTRODUCTION: Fetal echogenic bowel is a frequent sonographic finding, demonstrated in about 1% of pregnancies. The advised evaluation of fetal echogenic bowel includes maternal serology, genetic testing for cystic fibrosis, detailed sonographic anatomic survey, and invasive prenatal testing for fetal chromosomal aberrations. The objective of our study was to evaluate the risk for clinically significant chromosomal microarray analysis (CMA) findings in pregnancies with isolated echogenic bowel. METHODS: Data from all CMA analyses performed due to isolated echogenic bowel reported to the Israeli Ministry of Health between January 2013 and September 2016 were retrospectively obtained. Risk estimation was performed comparing the rate of abnormal microarray findings to the control population, based on a systematic review of 9272 pregnancies and a large local cohort of 5541 fetuses with normal ultrasound, undergoing CMA testing due to maternal request. RESULTS: Of 103 CMA analyses performed due to isolated echogenic bowel, two (1.94%) pathogenic findings were detected (47,XYY and 16p11.2 duplication). This risk was not significantly elevated compared to the control groups. In addition, three variants of unknown significance were demonstrated. CONCLUSIONS: To our best knowledge, our study is the first report describing the rate of clinically significant copy number variants in pregnancies with isolated echogenic bowel. According to our results, it seems that pregnancies with isolated echogenic bowel do not have an increased risk for abnormal CMA compared to fetuses with no evidence of sonographic anomalies. Our findings suggest that the consideration to perform CMA analysis in such pregnancies should not differ from any pregnancy with normal ultrasound.
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Aberraciones Cromosómicas , Intestino Ecogénico/diagnóstico por imagen , Enfermedades Fetales/genética , Diagnóstico Prenatal/métodos , Femenino , Enfermedades Fetales/diagnóstico por imagen , Humanos , Análisis por Micromatrices , Embarazo , Estudios Retrospectivos , Ultrasonografía PrenatalRESUMEN
Primary ovarian insufficiency (POI) is characterized by amenorrhea and loss or dysfunction of ovarian follicles prior to the age of 40. POI has been associated with autosomal recessive mutations in genes involving hormonal signaling and folliculogenesis, however, the genetic etiology of POI most often remains unknown. Here we report MRPS22 homozygous missense variants c.404G>A (p.R135Q) and c.605G>A (p.R202H) identified in four females from two independent consanguineous families as a novel genetic cause of POI in adolescents. Both missense mutations identified in MRPS22 are rare, occurred in highly evolutionarily conserved residues, and are predicted to be deleterious to protein function. In contrast to prior reports of mutations in MRPS22 associated with severe mitochondrial disease, the POI phenotype is far less severe. Consistent with this genotype-phenotype correlation, mitochondrial defects in oxidative phosphorylation or rRNA levels were not detected in fibroblasts derived from the POI patients, suggesting a non-bioenergetic or tissue-specific mitochondrial defect. Furthermore, we demonstrate in a Drosophila model that mRpS22 deficiency specifically in somatic cells of the ovary had no effect on fertility, whereas flies with mRpS22 deficiency specifically in germ cells were infertile and agametic, demonstrating a cell autonomous requirement for mRpS22 in germ cell development. These findings collectively identify that MRPS22, a component of the small mitochondrial ribosome subunit, is critical for ovarian development and may therefore provide insight into the pathophysiology and treatment of ovarian dysfunction.
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Proteínas de Drosophila/genética , Fertilidad/genética , Proteínas Mitocondriales/genética , Insuficiencia Ovárica Primaria/genética , Proteínas Ribosómicas/genética , Adolescente , Adulto , Amenorrea/genética , Amenorrea/patología , Animales , Modelos Animales de Enfermedad , Drosophila/genética , Femenino , Fertilidad/fisiología , Homocigoto , Humanos , Menopausia Prematura/genética , Mutación Missense/genética , Folículo Ovárico/patología , Insuficiencia Ovárica Primaria/patología , Adulto JovenRESUMEN
OBJECTIVE: To examine the risk for clinically significant chromosomal microarray analysis (CMA) findings in fetal right aortic arch (RAA). METHODS: Data from all CMA analyses performed owing to isolated RAA reported to the Israeli Ministry of Health between January 2013 and September 2016 were evaluated retrospectively. Risk for abnormal CMA findings was compared with two control populations, based on both previously described 9272 pregnancies with normal ultrasound, and on a local cohort of 5541 pregnancies undergoing CMA testing owing to maternal request. In addition, Pubmed database search was conducted for original researches examining this issue. RESULTS: Of 94 CMA analyses performed owing to isolated RAA, six (6.4%) pathogenic findings were detected (47,XX + 21; 45,X; two 22q11.2 microdeletions; 10p15.3 microdeletion and 16p11.2 duplication). Compared with control groups, an isolated RAA yielded a significantly increased relative risk for abnormal CMA results. Literature search yielded two additional retrospective studies describing microarray testing in RAA and encompassing 57 cases. The overall risk for clinically significant CMA findings was 6.62% (10/151). CONCLUSIONS: CMA testing is indicated in cases of prenatal isolated RAA, even in the era of advanced sonographic equipment, routine biochemical screening for Down syndrome and available non-invasive prenatal testing.
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Aorta Torácica/diagnóstico por imagen , Aberraciones Cromosómicas , Enfermedades Fetales/genética , Análisis por Micromatrices , Diagnóstico Prenatal/métodos , Adulto , Síndrome de Down/diagnóstico , Síndrome de Down/genética , Femenino , Enfermedades Fetales/diagnóstico , Humanos , Embarazo , Estudios Retrospectivos , Ultrasonografía PrenatalRESUMEN
BackgroundThe objective of our study was to examine the risk for submicroscopic chromosomal aberrations among fetuses with apparently isolated solitary kidney.MethodsData acquisition was performed retrospectively by searching Israeli Ministry of Health-computerized database. All cases having chromosomal microarray analysis (CMA), referred because of an indication of isolated unilateral kidney agenesis between January 2013 and September 2016, were included. Rate of clinically significant CMA findings in these pregnancies was compared to pregnancies with normal ultrasound, based on a systematic review encompassing 9,792 cases and local data of 5,541 pregnancies undergoing CMA because of maternal request.ResultsOf the 81 pregnancies with isolated solitary kidney, 2 (2.47%) loss-of-copy number variants compatible with well-described deletion syndromes were reported (16p11.2-16p12.2 and 22q11.21 microdeletion syndromes). In addition, one variant of unknown significance was demonstrated. The relative risk for pathogenic CMA findings among pregnancies with isolated unilateral renal agenesis was not significantly different compared with the control population.ConclusionCMA analysis in pregnancies with unilateral renal agenesis might still be useful, to the same degree as it can be in the general population.
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Aberraciones Cromosómicas/embriología , Riñón/anomalías , Riñón/embriología , Análisis de Secuencia por Matrices de Oligonucleótidos , Riñón Único/diagnóstico por imagen , Riñón Único/embriología , Adulto , Deleción Cromosómica , Cromosomas Humanos Par 16 , Cromosomas Humanos Par 22/genética , Femenino , Estudios de Asociación Genética , Humanos , Masculino , Edad Materna , Embarazo , Estudios Retrospectivos , Riesgo , Riñón Único/genética , Ultrasonografía PrenatalRESUMEN
Heterozygote GBA (glucosylceramidase beta) mutations increase the risk of Parkinson's disease (PD). Data based on the measured frequencies of GBA mutated alleles in the healthy population suggest that severe GBA mutations are associated with even higher risk for PD. These data, however, are prone to methodological biases resulting from the rarity of severe mutations and from ethnic-dependent differences in allele frequencies. To overcome these biases, we traced 13 Gaucher disease (GD) patients who were compound heterozygotes for one mild (N370S) and one severe GBA mutation and who reported a parent with PD. We determined the GBA mutation status of all parents and examined them whenever possible. While 50% of the parents carried a mild GBA mutation, we hypothesized that PD cases would be more likely to carry a severe mutation. We found that 10/13 PD parents had a severe mutation and only 3/10 carried a mild mutation (binomial test P<0.05). Using an unbiased methodology, we show that carriers of severe GBA mutations are at higher risk for PD relative to carriers of the mild mutations.
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Glucosilceramidasa/genética , Mutación , Enfermedad de Parkinson/genética , Anciano , Alelos , Femenino , Frecuencia de los Genes , Predisposición Genética a la Enfermedad , Genotipo , Heterocigoto , Humanos , Masculino , Persona de Mediana Edad , Linaje , Mutación PuntualRESUMEN
We assessed the molecular characteristics and the frequency of mutations in mismatch-repair genes among Bedouin patients with colorectal cancer (CRC) in Israel. Bedouin patients with a diagnosis of CRC at a major hospital in the southern part of Israel were deemed eligible for this study. The primary screening method was immunohistochemical staining for mismatch-repair proteins (MLH1, MSH2, MSH6, and PMS2). For subjects with abnormal immunohistochemical staining, we performed microsatellite instability (MSI) analyses, and for tumors with a loss of MLH1 expression we also performed BRAF testing. In MSI high cases we searched further for germline mutations. Of the 24 patients enrolled, four subjects (16.7%) had MSI high tumors: one subject was found to harbor a biallelic PMS2 mutation, one subject had Lynch syndrome (LS) with MSH6 mutation and two subjects had a loss of MLH1/PMS2 proteins/BRAF wild type/normal MLH1 sequence. Ten patients (41.7%) were younger than 50 at the time of diagnosis and none had first degree relatives with CRC. In conclusion, in this cohort of 24 consecutive Arab Bedouins with CRC, one patient was found to harbor a constitutional mismatch repair deficiency, one patient had LS with MSH6 mutation, and two patients had unresolved loss of MLH1/PMS2 proteins/BRAF wild type phenotype.
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Árabes/genética , Biomarcadores de Tumor/genética , Neoplasias Encefálicas/epidemiología , Neoplasias Colorrectales Hereditarias sin Poliposis/epidemiología , Neoplasias Colorrectales Hereditarias sin Poliposis/genética , Neoplasias Colorrectales/epidemiología , Síndromes Neoplásicos Hereditarios/epidemiología , Adulto , Neoplasias Encefálicas/genética , Neoplasias Colorrectales/genética , Femenino , Estudios de Seguimiento , Pruebas Genéticas/métodos , Mutación de Línea Germinal , Humanos , Israel/epidemiología , Masculino , Persona de Mediana Edad , Síndromes Neoplásicos Hereditarios/genética , PrevalenciaAsunto(s)
Anticuerpos Monoclonales Humanizados/uso terapéutico , Antígenos CD55/genética , Mutación del Sistema de Lectura , Enteropatías Perdedoras de Proteínas/tratamiento farmacológico , Enteropatías Perdedoras de Proteínas/genética , Niño , Preescolar , Ensayos de Uso Compasivo , Activación de Complemento , Complejo de Ataque a Membrana del Sistema Complemento/metabolismo , Diarrea/etiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Linaje , Análisis de Secuencia de ADN , Albúmina Sérica/metabolismo , Adulto JovenRESUMEN
Glycine is a major neurotransmitter that activates inhibitory glycine receptors and is a co-agonist for excitatory glutamatergic N-methyl-D-aspartate (NMDA) receptors. Two transporters, GLYT1 and GLYT2, regulate extracellular glycine concentrations within the CNS. Dysregulation of the extracellular glycine has been associated with hyperekplexia and nonketotic hyperglycinemia. Here, we report four individuals from two families who presented at birth with facial dysmorphism, encephalopathy, arthrogryposis, hypotonia progressing to hypertonicity with startle-like clonus, and respiratory failure. Only one individual survived the respiratory failure and was weaned off ventilation but has significant global developmental delay. Mildly elevated cerebrospinal fluid (CSF) glycine and normal serum glycine were observed in two individuals. In both families, we identified truncating mutations in SLC6A9, encoding GLYT1. We demonstrate that pharmacologic or genetic abolishment of GlyT1 activity in mice leads to mildly elevated glycine in the CSF but not in blood. Additionally, previously reported slc6a9-null mice and zebrafish mutants also display phenotypes consistent with the affected individuals we examined. Our data suggest that truncating SLC6A9 mutations lead to a distinct human neurological syndrome hallmarked by mildly elevated CSF glycine and normal serum glycine.
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Artrogriposis/genética , Proteínas de Transporte de Glicina en la Membrana Plasmática/genética , Glicina/líquido cefalorraquídeo , Hiperglicinemia no Cetósica/genética , Animales , Artrogriposis/diagnóstico , Preescolar , Femenino , Eliminación de Gen , Regulación de la Expresión Génica , Glicina/sangre , Proteínas de Transporte de Glicina en la Membrana Plasmática/metabolismo , Humanos , Hiperglicinemia no Cetósica/diagnóstico , Lactante , Recién Nacido , Masculino , Ratones , Ratones Noqueados , LinajeRESUMEN
BACKGROUND: Next generation sequencing (NGS) provides a key technology for deciphering the genetic underpinnings of human diseases. Typical NGS analyses of a patient depict tens of thousands non-reference coding variants, but only one or very few are expected to be significant for the relevant disorder. In a filtering stage, one employs family segregation, rarity in the population, predicted protein impact and evolutionary conservation as a means for shortening the variation list. However, narrowing down further towards culprit disease genes usually entails laborious seeking of gene-phenotype relationships, consulting numerous separate databases. Thus, a major challenge is to transition from the few hundred shortlisted genes to the most viable disease-causing candidates. RESULTS: We describe a novel tool, VarElect ( http://ve.genecards.org ), a comprehensive phenotype-dependent variant/gene prioritizer, based on the widely-used GeneCards, which helps rapidly identify causal mutations with extensive evidence. The GeneCards suite offers an effective and speedy alternative, whereby >120 gene-centric automatically-mined data sources are jointly available for the task. VarElect cashes on this wealth of information, as well as on GeneCards' powerful free-text Boolean search and scoring capabilities, proficiently matching variant-containing genes to submitted disease/symptom keywords. The tool also leverages the rich disease and pathway information of MalaCards, the human disease database, and PathCards, the unified pathway (SuperPaths) database, both within the GeneCards Suite. The VarElect algorithm infers direct as well as indirect links between genes and phenotypes, the latter benefitting from GeneCards' diverse gene-to-gene data links in GenesLikeMe. Finally, our tool offers an extensive gene-phenotype evidence portrayal ("MiniCards") and hyperlinks to the parent databases. CONCLUSIONS: We demonstrate that VarElect compares favorably with several often-used NGS phenotyping tools, thus providing a robust facility for ranking genes, pointing out their likelihood to be related to a patient's disease. VarElect's capacity to automatically process numerous NGS cases, either in stand-alone format or in VCF-analyzer mode (TGex and VarAnnot), is indispensable for emerging clinical projects that involve thousands of whole exome/genome NGS analyses.