RESUMEN

Evaluation of expression profile in autism spectrum disorder (ASD) patients is an important approach to understand possible similar functional consequences that may underlie disease pathophysiology regardless of its genetic heterogeneity. Induced pluripotent stem cell (iPSC)-derived neuronal models have been useful to explore this question, but larger cohorts and different ASD endophenotypes still need to be investigated. Moreover, whether changes seen in this in vitro model reflect previous findings in ASD postmortem brains and how consistent they are across the studies remain underexplored questions. We examined the transcriptome of iPSC-derived neuronal cells from a normocephalic ASD cohort composed mostly of high-functioning individuals and from non-ASD individuals. ASD patients presented expression dysregulation of a module of co-expressed genes involved in protein synthesis in neuronal progenitor cells (NPC), and a module of genes related to synapse/neurotransmission and a module related to translation in neurons. Proteomic analysis in NPC revealed potential molecular links between the modules dysregulated in NPC and in neurons. Remarkably, the comparison of our results to a series of transcriptome studies revealed that the module related to synapse has been consistently found as upregulated in iPSC-derived neurons-which has an expression profile more closely related to fetal brain-while downregulated in postmortem brain tissue, indicating a reliable association of this network to the disease and suggesting that its dysregulation might occur in different directions across development in ASD individuals. Therefore, the expression pattern of this network might be used as biomarker for ASD and should be experimentally explored as a therapeutic target.

Asunto(s)

Trastorno del Espectro Autista , Células Madre Pluripotentes Inducidas , Trastorno del Espectro Autista/genética , Humanos , Neuronas , Proteómica , Transcriptoma/genética

RESUMEN

The capacity to fully replace teeth continuously makes zebrafish an attractive model to explore regeneration and tooth development. The requirement of attachment bone for the appearance of replacement teeth has been hypothesized but not yet investigated. The transcription factor sp7 (osterix) is known in mammals to play an important role during odontoblast differentiation and root formation. Here we study tooth replacement in the absence of attachment bone using sp7 zebrafish mutants. We analysed the pattern of tooth replacement at different stages of development and demonstrated that in zebrafish lacking sp7, attachment bone is never present, independent of the stage of tooth development or fish age, yet replacement is not interrupted. Without bone of attachment we observed abnormal orientation of teeth, and abnormal connection of pulp cavities of predecessor and replacement teeth. Mutants lacking sp7 show arrested dentinogenesis, with non-polarization of odontoblasts and only a thin layer of dentin deposited. Osteoclast activity was observed in sp7 mutants; due to the lack of bone of attachment, remodelling was diminished but nevertheless present along the pharyngeal bone. We conclude that tooth replacement is ongoing in the sp7 mutant despite poor differentiation and defective attachment. Without bone of attachment tooth orientation and pulp organization are compromised.

Asunto(s)

Dentinogénesis/genética , Odontogénesis/genética , Factor de Transcripción Sp7/fisiología , Anomalías Dentarias/genética , Proteínas de Pez Cebra/fisiología , Pez Cebra/genética , Proceso Alveolar/patología , Animales , Animales Modificados Genéticamente , Pulpa Dental/patología , Dentina/anomalías , Dentinogénesis/fisiología , Regulación del Desarrollo de la Expresión Génica , Genes Reporteros , Odontoblastos/patología , Odontogénesis/fisiología , Osteoclastos/metabolismo , Regeneración , Factor de Transcripción Sp7/deficiencia , Factor de Transcripción Sp7/genética , Raíz del Diente/patología , Proteínas de Pez Cebra/deficiencia , Proteínas de Pez Cebra/genética

RESUMEN

A valuable approach to understand how individual and population genetic differences can predispose to disease is to assess the impact of genetic variants on cellular functions (e.g., gene expression) of cell and tissue types related to pathological states. To understand the genetic basis of nonsyndromic cleft lip with or without cleft palate (NSCL/P) susceptibility, a complex and highly prevalent congenital malformation, we searched for genetic variants with a regulatory role in a disease-related tissue, the lip muscle (orbicularis oris muscle [OOM]), of affected individuals. From 46 OOM samples, which are frequently discarded during routine corrective surgeries on patients with orofacial clefts, we derived mesenchymal stem cells and correlated the individual genetic variants with gene expression from these cultured cells. Through this strategy, we detected significant cis-eQTLs (i.e., DNA variants affecting gene expression) and selected a few candidates to conduct an association study in a large Brazilian cohort (624 patients and 668 controls). This resulted in the discovery of a novel susceptibility locus for NSCL/P, rs1063588, the best eQTL for the MRPL53 gene, where evidence for association was mostly driven by the Native American ancestry component of our Brazilian sample. MRPL53 (2p13.1) encodes a 39S protein subunit of mitochondrial ribosomes and interacts with MYC, a transcription factor required for normal facial morphogenesis. Our study illustrates not only the importance of sampling admixed populations but also the relevance of measuring the functional effects of genetic variants over gene expression to dissect the complexity of disease phenotypes.

Asunto(s)

Labio Leporino/genética , Fisura del Paladar/genética , Proteínas Ribosómicas/genética , Adolescente , Niño , Preescolar , Femenino , Genes/genética , Estudio de Asociación del Genoma Completo , Humanos , Lactante , Recién Nacido , Masculino , Ribosomas Mitocondriales/metabolismo , Análisis de Secuencia por Matrices de Oligonucleótidos , Polimorfismo de Nucleótido Simple/genética , Sitios de Carácter Cuantitativo/genética , Adulto Joven

RESUMEN

Richieri-Costa-Pereira syndrome is a rare autosomal recessive acrofacial dysostosis that has been mainly described in Brazilian individuals. The cardinal features include Robin sequence, cleft mandible, laryngeal anomalies and limb defects. A biallelic expansion of a complex repeated motif in the 5' untranslated region of EIF4A3 has been shown to cause this syndrome, commonly with 15 or 16 repeats. The only patient with mild clinical findings harbored a 14-repeat expansion in 1 allele and a point mutation in the other allele. This proband is described here in more details, as well as is his affected sister, and 5 new individuals with Richieri-Costa-Pereira syndrome, including a patient from England, of African ancestry. This study has expanded the phenotype in this syndrome by the observation of microcephaly, better characterization of skeletal abnormalities, less severe phenotype with only mild facial dysmorphisms and limb anomalies, as well as the absence of cleft mandible, which is a hallmark of the syndrome. Although the most frequent mutation in this study was the recurrent 16-repeat expansion in EIF4A3, there was an overrepresentation of the 14-repeat expansion, with mild phenotypic expression, thus suggesting that the number of these motifs could play a role in phenotypic delineation.

Asunto(s)

Pie Equinovaro/genética , ARN Helicasas DEAD-box/genética , Factor 4A Eucariótico de Iniciación/genética , Deformidades Congénitas de la Mano/genética , Laringe/fisiopatología , Deformidades Congénitas de las Extremidades/genética , Síndrome de Pierre Robin/genética , Adolescente , Adulto , Alelos , Brasil/epidemiología , Niño , Pie Equinovaro/epidemiología , Pie Equinovaro/fisiopatología , Expansión de las Repeticiones de ADN/genética , Inglaterra/epidemiología , Extremidades/fisiopatología , Femenino , Genotipo , Deformidades Congénitas de la Mano/epidemiología , Deformidades Congénitas de la Mano/fisiopatología , Humanos , Laringe/anomalías , Deformidades Congénitas de las Extremidades/fisiopatología , Masculino , Fenotipo , Síndrome de Pierre Robin/epidemiología , Síndrome de Pierre Robin/fisiopatología , Mutación Puntual/genética , Adulto Joven

RESUMEN

Non-syndromic cleft lip with or without cleft palate (NSCL/P) is a prevalent, complex congenital malformation. Genome-wide association studies (GWAS) on NSCL/P have consistently identified association for the 1p22 region, in which ARHGAP29 has emerged as the main candidate gene. ARHGAP29 re-sequencing studies in NSCL/P patients have identified rare variants; however, their clinical impact is still unclear. In this study we identified 10 rare variants in ARHGAP29, including five missense, one in-frame deletion, and four loss-of-function (LoF) variants, in a cohort of 188 familial NSCL/P cases. A significant mutational burden was found for LoF (Sequence Kernel Association Test, p = 0.0005) but not for missense variants in ARHGAP29, suggesting that only LoF variants contribute to the etiology of NSCL/P. Penetrance was estimated as 59%, indicating that heterozygous LoF variants in ARHGAP29 confer a moderate risk to NSCL/P. The GWAS hits in IRF6 (rs642961) and 1p22 (rs560426 and rs4147811) do not seem to contribute to the penetrance of the phenotype, based on co-segregation analysis. Our data show that rare variants leading to haploinsufficiency of ARHGAP29 represent an important etiological clefting mechanism, and genetic testing for this gene might be taken into consideration in genetic counseling of familial cases.

Asunto(s)

Labio Leporino/genética , Fisura del Paladar/genética , Proteínas Activadoras de GTPasa/genética , Mutación , Femenino , Proteínas Activadoras de GTPasa/metabolismo , Estudio de Asociación del Genoma Completo , Humanos , Masculino , Mutación Missense

RESUMEN

The spliceosome is a large ribonucleoprotein complex that removes introns from pre-mRNA transcripts. Mutations in EFTUD2, encoding a component of the major spliceosome, have recently been identified as the cause of mandibulofacial dysostosis, Guion-Almeida type (MFDGA), characterized by mandibulofacial dysostosis, microcephaly, external ear malformations and intellectual disability. Mutations in several other genes involved in spliceosomal function or linked aspects of mRNA processing have also recently been identified in human disorders with specific craniofacial malformations: SF3B4 in Nager syndrome, an acrofacial dysostosis (AFD); SNRPB in cerebrocostomandibular syndrome, characterized by Robin sequence and rib defects; EIF4A3 in the AFD Richieri-Costa-Pereira syndrome, characterized by Robin sequence, median mandibular cleft and limb defects; and TXNL4A in Burn-McKeown syndrome, involving specific craniofacial dysmorphisms. Here, we review phenotypic and molecular aspects of these syndromes. Given the apparent sensitivity of craniofacial development to defects in mRNA processing, it is possible that mutations in other proteins involved in spliceosomal function will emerge in the future as causative for related human disorders.

Asunto(s)

Atresia de las Coanas/metabolismo , Pie Equinovaro/metabolismo , Sordera/congénito , Deformidades Congénitas de la Mano/metabolismo , Cardiopatías Congénitas/metabolismo , Discapacidad Intelectual/metabolismo , Disostosis Mandibulofacial/metabolismo , Micrognatismo/metabolismo , Mutación , Síndrome de Pierre Robin/metabolismo , Costillas/anomalías , Empalmosomas/metabolismo , Atresia de las Coanas/genética , Pie Equinovaro/genética , ARN Helicasas DEAD-box/genética , Sordera/genética , Sordera/metabolismo , Factor 4A Eucariótico de Iniciación/genética , Facies , Femenino , Deformidades Congénitas de la Mano/genética , Cardiopatías Congénitas/genética , Humanos , Discapacidad Intelectual/genética , Masculino , Disostosis Mandibulofacial/genética , Micrognatismo/genética , Factores de Elongación de Péptidos/genética , Síndrome de Pierre Robin/genética , Factores de Empalme de ARN , Proteínas de Unión al ARN/genética , Ribonucleoproteína Nuclear Pequeña U5/genética , Costillas/metabolismo , Empalmosomas/genética

Asunto(s)

Trastorno del Espectro Autista/patología , Regulación de la Expresión Génica/fisiología , Células Madre Multipotentes/metabolismo , Complejos Multiproteicos/metabolismo , Transducción de Señal/fisiología , Serina-Treonina Quinasas TOR/metabolismo , Androstadienos/farmacología , Estudios de Casos y Controles , Diferenciación Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Células Cultivadas , Niño , Medio de Cultivo Libre de Suero/farmacología , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , Inmunosupresores/farmacología , Masculino , Diana Mecanicista del Complejo 1 de la Rapamicina , Células Madre Multipotentes/efectos de los fármacos , Fosforilación/efectos de los fármacos , Suero/metabolismo , Transducción de Señal/efectos de los fármacos , Sirolimus/farmacología , Factores de Tiempo , Wortmanina

RESUMEN

An increasing number of genetic variants have been implicated in autism spectrum disorders (ASDs), and the functional study of such variants will be critical for the elucidation of autism pathophysiology. Here, we report a de novo balanced translocation disruption of TRPC6, a cation channel, in a non-syndromic autistic individual. Using multiple models, such as dental pulp cells, induced pluripotent stem cell (iPSC)-derived neuronal cells and mouse models, we demonstrate that TRPC6 reduction or haploinsufficiency leads to altered neuronal development, morphology and function. The observed neuronal phenotypes could then be rescued by TRPC6 complementation and by treatment with insulin-like growth factor-1 or hyperforin, a TRPC6-specific agonist, suggesting that ASD individuals with alterations in this pathway may benefit from these drugs. We also demonstrate that methyl CpG binding protein-2 (MeCP2) levels affect TRPC6 expression. Mutations in MeCP2 cause Rett syndrome, revealing common pathways among ASDs. Genetic sequencing of TRPC6 in 1041 ASD individuals and 2872 controls revealed significantly more nonsynonymous mutations in the ASD population, and identified loss-of-function mutations with incomplete penetrance in two patients. Taken together, these findings suggest that TRPC6 is a novel predisposing gene for ASD that may act in a multiple-hit model. This is the first study to use iPSC-derived human neurons to model non-syndromic ASD and illustrate the potential of modeling genetically complex sporadic diseases using such cells.

Asunto(s)

Trastorno Autístico/patología , Neuronas/patología , Canales Catiónicos TRPC/metabolismo , Animales , Protocolos de Quimioterapia Combinada Antineoplásica/metabolismo , Trastorno Autístico/genética , Trastorno Autístico/fisiopatología , Carboplatino/metabolismo , Diferenciación Celular/genética , Línea Celular , Proliferación Celular/genética , Células Cultivadas , Niño , Modelos Animales de Enfermedad , Embrión de Mamíferos , Etopósido/metabolismo , Regulación de la Expresión Génica/genética , Humanos , Técnicas In Vitro , Células Madre Pluripotentes Inducidas/fisiología , Potenciales Postsinápticos Inhibidores/genética , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Mitoxantrona/metabolismo , Mutación/genética , Neuronas/metabolismo , Prednisolona/metabolismo , Transducción de Señal/genética , Canales Catiónicos TRPC/genética , Canal Catiónico TRPC6

RESUMEN

Inclusion body myopathy associated with Paget disease and frontotemporal dementia (IBMPFD) is a progressive and usually misdiagnosed autosomal dominant disorder. It is clinically characterized by a triad of features: proximal and distal myopathy, early onset Paget disease of bone (PDB), and frontotemporal dementia (FTD). It is caused by missense mutations in the valosin-containing protein (VCP) gene. We describe here the clinical and molecular findings of the first Brazilian family identified with IBMPFD. Progressive myopathy affecting the limb girdles was detected by clinical examination followed by muscle biopsy and creatine kinase measurement. PDB was suggested after anatomopathological bone examination and FTD was diagnosed by clinical, neuropsychological and language evaluations. Brain magnetic resonance revealed severe atrophy of the anterior temporal lobes, including the hippocampi. A R93C mutation in VCP was detected by direct sequencing screening in subject W (age 62) and in his mother. Four more individuals diagnosed with "dementia" were reported in this family. We also present a comprehensive genotype-phenotype correlation analysis of mutations in VCP in 182 patients from 29 families described in the literature and show that while IBM is a conspicuously penetrant symptom, PDB has a lower penetrance when associated with mutations in the AAAD1 domain and FTD has a lower penetrance when associated with mutations in the Junction (L1-D1) domain. Furthermore, the R93C mutation is likely to be associated with the penetrance of all the clinical symptoms of the triad.

Asunto(s)

Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adenosina Trifosfatasas/genética , Proteínas de Ciclo Celular/genética , Demencia Frontotemporal/genética , Estudios de Asociación Genética , Mutación/genética , Miositis por Cuerpos de Inclusión/genética , Osteítis Deformante/genética , Demencia Frontotemporal/complicaciones , Imagen por Resonancia Magnética , Miositis por Cuerpos de Inclusión/complicaciones , Osteítis Deformante/complicaciones , Linaje

RESUMEN

Inclusion body myopathy associated with Paget disease and frontotemporal dementia (IBMPFD) is a progressive and usually misdiagnosed autosomal dominant disorder. It is clinically characterized by a triad of features: proximal and distal myopathy, early onset Paget disease of bone (PDB), and frontotemporal dementia (FTD). It is caused by missense mutations in the valosin-containing protein (VCP) gene. We describe here the clinical and molecular findings of the first Brazilian family identified with IBMPFD. Progressive myopathy affecting the limb girdles was detected by clinical examination followed by muscle biopsy and creatine kinase measurement. PDB was suggested after anatomopathological bone examination and FTD was diagnosed by clinical, neuropsychological and language evaluations. Brain magnetic resonance revealed severe atrophy of the anterior temporal lobes, including the hippocampi. A R93C mutation in VCP was detected by direct sequencing screening in subject W (age 62) and in his mother. Four more individuals diagnosed with "dementia" were reported in this family. We also present a comprehensive genotype-phenotype correlation analysis of mutations in VCP in 182 patients from 29 families described in the literature and show that while IBM is a conspicuously penetrant symptom, PDB has a lower penetrance when associated with mutations in the AAAD1 domain and FTD has a lower penetrance when associated with mutations in the Junction (L1-D1) domain. Furthermore, the R93C mutation is likely to be associated with the penetrance of all the clinical symptoms of the triad.

Asunto(s)

Adenosina Trifosfatasas/genética , Proteínas de Ciclo Celular/genética , Demencia Frontotemporal/genética , Estudios de Asociación Genética , Mutación/genética , Miositis por Cuerpos de Inclusión/genética , Osteítis Deformante/genética , Anciano , Anciano de 80 o más Años , Femenino , Demencia Frontotemporal/complicaciones , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Miositis por Cuerpos de Inclusión/complicaciones , Osteítis Deformante/complicaciones , Linaje , Proteína que Contiene Valosina

RESUMEN

Autism spectrum disorders (ASD) is a group of behaviorally defined neurodevelopmental disabilities characterized by multiple genetic etiologies and a complex presentation. Several studies suggest the involvement of the serotonin system in the development of ASD, but only few have investigated serotonin receptors. We have performed a case-control and a family-based study with 9 polymorphisms mapped to two serotonin receptor genes (HTR1B and HTR2C) in 252 Brazilian male ASD patients of European ancestry. These analyses showed evidence of undertransmission of the HTR1B haplotypes containing alleles -161G and -261A at HTR1B gene to ASD (P=0.003), but no involvement of HTR2C to the predisposition to this disease. Considering the relatively low level of statistical significance and the power of our sample, further studies are required to confirm the association of these serotonin-related genes and ASD.

Asunto(s)

Trastorno Autístico/genética , Predisposición Genética a la Enfermedad , Polimorfismo de Nucleótido Simple , Receptor de Serotonina 5-HT1B/genética , Receptor de Serotonina 5-HT2C/genética , Alelos , Brasil , Estudios de Casos y Controles , Familia , Genotipo , Haplotipos , Humanos , Masculino , Análisis de Secuencia de ADN

RESUMEN

Association studies between ADIPOR1 genetic variants and predisposition to type 2 diabetes (DM2) have provided contradictory results. We determined if two single nucleotide polymorphisms (SNP c.-8503G>A and SNP c.10225C>G) in regulatory regions of ADIPOR1 in 567 Brazilian individuals of European (EA; N = 443) or African (AfA; N = 124) ancestry from rural (quilombo remnants; N = 439) and urban (N = 567) areas. We detected a significant effect of ethnicity on the distribution of the allelic frequencies of both SNPs in these populations (EA: -8503A = 0.27; AfA: -8503A = 0.16; P = 0.001 and EA: 10225G = 0.35; AfA: 10225G = 0.51; P < 0.001). Neither of the polymorphisms were associated with DM2 in the case-control study in EA (SNP c.-8503G>A: DM2 group -8503A = 0.26; control group -8503A = 0.30; P = 0.14/SNP 10225C>G: DM2 group 10225G = 0.37; control group 10225G = 0.32; P = 0.40) and AfA populations (SNP c.-8503G>A: DM2 group -8503A = 0.16; control group -8503A = 0.15; P = 0.34/SNP 10225C>G: DM2 group 10225G = 0.51; control group 10225G = 0.52; P = 0.50). Similarly, none of the polymorphisms were associated with metabolic/anthropometric risk factors for DM2 in any of the three populations, except for HDL cholesterol, which was significantly higher in AfA heterozygotes (GC = 53.75 +/- 17.26 mg/dL) than in homozygotes. We conclude that ADIPOR1 polymorphisms are unlikely to be major risk factors for DM2 or for metabolic/anthropometric measurements that represent risk factors for DM2 in populations of European and African ancestries.

Asunto(s)

Índice de Masa Corporal , Diabetes Mellitus Tipo 2/genética , Polimorfismo de Nucleótido Simple/genética , Receptores de Adiponectina/genética , Población Negra/genética , Brasil , Estudios de Casos y Controles , Femenino , Frecuencia de los Genes , Predisposición Genética a la Enfermedad/genética , Genotipo , Humanos , Masculino , Persona de Mediana Edad , Factores de Riesgo , Población Blanca/genética

RESUMEN

We report the identification of a novel mutation at a highly conserved residue within the N-terminal region of spermine synthase (SMS) in a second family with Snyder-Robinson X-linked mental retardation syndrome (OMIM 309583). This missense mutation, p.G56S, greatly reduces SMS activity and leads to severe epilepsy and cognitive impairment. Our findings contribute to a better delineation and expansion of the clinical spectrum of Snyder-Robinson syndrome, support the important role of the N-terminus in the function of the SMS protein, and provide further evidence for the importance of SMS activity in the development of intellectual processing and other aspects of human development.

Asunto(s)

Discapacidad Intelectual Ligada al Cromosoma X/genética , Mutación Missense , Espermina Sintasa/genética , Adulto , Niño , Análisis Mutacional de ADN , Femenino , Genes Recesivos , Humanos , Masculino , Linaje , Síndrome

RESUMEN

Association studies between ADIPOR1 genetic variants and predisposition to type 2 diabetes (DM2) have provided contradictory results. We determined if two single nucleotide polymorphisms (SNP c.-8503G>A and SNP c.10225C>G) in regulatory regions of ADIPOR1 in 567 Brazilian individuals of European (EA; N = 443) or African (AfA; N = 124) ancestry from rural (quilombo remnants; N = 439) and urban (N = 567) areas. We detected a significant effect of ethnicity on the distribution of the allelic frequencies of both SNPs in these populations (EA: -8503A = 0.27; AfA: -8503A = 0.16; P = 0.001 and EA: 10225G = 0.35; AfA: 10225G = 0.51; P < 0.001). Neither of the polymorphisms were associated with DM2 in the case-control study in EA (SNP c.-8503G>A: DM2 group -8503A = 0.26; control group -8503A = 0.30; P = 0.14/SNP 10225C>G: DM2 group 10225G = 0.37; control group 10225G = 0.32; P = 0.40) and AfA populations (SNP c.-8503G>A: DM2 group -8503A = 0.16; control group -8503A = 0.15; P = 0.34/SNP 10225C>G: DM2 group 10225G = 0.51; control group 10225G = 0.52; P = 0.50). Similarly, none of the polymorphisms were associated with metabolic/anthropometric risk factors for DM2 in any of the three populations, except for HDL cholesterol, which was significantly higher in AfA heterozygotes (GC = 53.75 ± 17.26 mg/dL) than in homozygotes. We conclude that ADIPOR1 polymorphisms are unlikely to be major risk factors for DM2 or for metabolic/anthropometric measurements that represent risk factors for DM2 in populations of European and African ancestries.

Asunto(s)

Femenino , Humanos , Masculino , Persona de Mediana Edad , Índice de Masa Corporal , /genética , Polimorfismo de Nucleótido Simple/genética , Receptores de Adiponectina/genética , Población Negra/genética , Brasil , Estudios de Casos y Controles , Población Blanca/genética , Frecuencia de los Genes , Genotipo , Predisposición Genética a la Enfermedad/genética , Factores de Riesgo

RESUMEN

We present the first comprehensive study, to our knowledge, on genomic chromosomal analysis in syndromic craniosynostosis. In total, 45 patients with craniosynostotic disorders were screened with a variety of methods including conventional karyotype, microsatellite segregation analysis, subtelomeric multiplex ligation-dependent probe amplification) and whole-genome array-based comparative genome hybridisation. Causative abnormalities were present in 42.2% (19/45) of the samples, and 27.8% (10/36) of the patients with normal conventional karyotype carried submicroscopic imbalances. Our results include a wide variety of imbalances and point to novel chromosomal regions associated with craniosynostosis. The high incidence of pure duplications or trisomies suggests that these are important mechanisms in craniosynostosis, particularly in cases involving the metopic suture.

Asunto(s)

Aberraciones Cromosómicas , Segregación Cromosómica , Craneosinostosis/genética , Repeticiones de Microsatélite , Humanos , Cariotipificación , Hibridación de Ácido Nucleico/métodos , Polimorfismo Genético

RESUMEN

We report array-CGH screening of 95 syndromic patients with normal G-banded karyotypes and at least one of the following features: mental retardation, heart defects, deafness, obesity, craniofacial dysmorphisms or urogenital tract malformations. Chromosome imbalances not previously detected in normal controls were found in 30 patients (31%) and at least 16 of them (17%) seem to be causally related to the abnormal phenotypes. Eight of the causative imbalances had not been described previously and pointed to new chromosome regions and candidate genes for specific phenotypes, including a connective tissue disease locus on 2p16.3, another for obesity on 7q22.1-->q22.3, and a candidate gene for the 3q29 deletion syndrome manifestations. The other causative alterations had already been associated with well-defined phenotypes including Sotos syndrome, and the 1p36 and 22q11.21 microdeletion syndromes. However, the clinical features of these latter patients were either not typical or specific enough to allow diagnosis before detection of chromosome imbalances. For instance, three patients with overlapping deletions in 22q11.21 were ascertained through entirely different clinical features, i.e., heart defect, utero-vaginal aplasia, and mental retardation associated with psychotic disease. Our results demonstrate that ascertainment through whole-genome screening of syndromic patients by array-CGH leads not only to the description of new syndromes, but also to the recognition of a broader spectrum of features for already described syndromes. Furthermore, on the technical side, we have significantly reduced the amount of reagents used and costs involved in the array-CGH protocol, without evident reduction in efficiency, bringing the method more within reach of centers with limited budgets.

Asunto(s)

Enfermedades Genéticas Congénitas , Genoma Humano , Hibridación de Ácido Nucleico , Adolescente , Niño , Preescolar , Bandeo Cromosómico , Femenino , Eliminación de Gen , Humanos , Lactante , Masculino , Mutación , Polimorfismo Genético , Síndrome

RESUMEN

Diabetes mellitus (DM) is a highly prevalent complex genetic disorder. There has been a worldwide effort in the identification of susceptibility genes for DM and its complications, and the 5-10-methylenetetrahydrofolate reductase (MTHFR) and apolipoprotein-E (APOE) genes have been considered good candidate susceptibility genes to this condition. The objectives of the present study were to determine if the 677T MTHFR and epsilon2/epsilon3/epsilon4 APOE alleles are risk factors for DM and for severity of diabetic retinopathy (DR). A total of 248 individuals were studied: 107 healthy individuals and 141 diabetic patients (46 with type 1 diabetes and 95 with type 2 diabetes), who also had DR (81 with non-proliferative DR and 60 with proliferative DR). The polymorphisms were analyzed by PCR followed by digestion with restriction enzyme or the single-nucleotide primer extension method. No evidence of association between the 677TT genotype of MTHFR gene and DM [cases: TT = 10/95 (10.6%); controls: TT = 14/107 (13%)] or with severity of DR was observed [cases: TT = 5/60 (8.5%); controls: TT = 9/81 (11.1%); P > 0.05]. We also did not find evidence of an association between APOE alleles and proliferative DR (epsilon2, epsilon3 and epsilon4 in cases: 9, 76, and 15%, and in controls: 5, 88, and 12%, respectively) but the carriers of epsilon2 allele were more frequent among patients with type 2 DM and DR than in controls [cases: 15/95 (15.8%); controls: 7/107 (6.5%); P < 0.05]. Therefore, our results suggest that the epsilon2 allele/APOE might be a risk factor for diabetes in the Brazilian population.

Asunto(s)

Apolipoproteínas E/genética , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 2/genética , Retinopatía Diabética/genética , Metilenotetrahidrofolato Reductasa (NADPH2)/genética , Anciano , Alelos , Estudios de Casos y Controles , Femenino , Frecuencia de los Genes , Predisposición Genética a la Enfermedad , Genotipo , Humanos , Masculino , Persona de Mediana Edad , Reacción en Cadena de la Polimerasa , Polimorfismo Genético , Factores de Riesgo , Índice de Severidad de la Enfermedad

RESUMEN

Diabetes mellitus (DM) is a highly prevalent complex genetic disorder. There has been a worldwide effort in the identification of susceptibility genes for DM and its complications, and the 5-10-methylenetetrahydrofolate reductase (MTHFR) and apolipoprotein-E (APOE) genes have been considered good candidate susceptibility genes to this condition. The objectives of the present study were to determine if the 677T MTHFR and epsilon2/epsilon3/epsilon4 APOE alleles are risk factors for DM and for severity of diabetic retinopathy (DR). A total of 248 individuals were studied: 107 healthy individuals and 141 diabetic patients (46 with type 1 diabetes and 95 with type 2 diabetes), who also had DR (81 with non-proliferative DR and 60 with proliferative DR). The polymorphisms were analyzed by PCR followed by digestion with restriction enzyme or the single-nucleotide primer extension method. No evidence of association between the 677TT genotype of MTHFR gene and DM [cases: TT = 10/95 (10.6 percent); controls: TT = 14/107 (13 percent)] or with severity of DR was observed [cases: TT = 5/60 (8.5 percent); controls: TT = 9/81 (11.1 percent); P > 0.05]. We also did not find evidence of an association between APOE alleles and proliferative DR (epsilon2, epsilon3 and epsilon4 in cases: 9, 76, and 15 percent, and in controls: 5, 88, and 12 percent, respectively) but the carriers of epsilon2 allele were more frequent among patients with type 2 DM and DR than in controls [cases: 15/95 (15.8 percent); controls: 7/107 (6.5 percent); P < 0.05]. Therefore, our results suggest that the epsilon2 allele/APOE might be a risk factor for diabetes in the Brazilian population.

Asunto(s)

Humanos , Persona de Mediana Edad , Apolipoproteínas E/genética , Diabetes Mellitus Tipo 1/genética , /genética , Retinopatía Diabética/genética , /genética , Alelos , Estudios de Casos y Controles , Frecuencia de los Genes , Predisposición Genética a la Enfermedad , Genotipo , Reacción en Cadena de la Polimerasa , Polimorfismo Genético , Factores de Riesgo , Índice de Severidad de la Enfermedad

RESUMEN

We report a novel 1 bp deletion (c.1834delC) in the MCT8 gene in a large Brazilian family with Allan-Herndon-Dudley syndrome (AHDS), an X linked condition characterised by severe mental retardation and neurological dysfunction. The c.1834delC segregates with the disease in this family and it was not present in 100 control chromosomes, further confirming its pathogenicity. This mutation causes a frameshift and the inclusion of 64 additional amino acids in the C-terminal region of the protein. Pathogenic mutations in the MCT8 gene, which encodes a thyroid hormone transporter, results in elevated serum triiodothyronine (T3) levels, which were confirmed in four affected males of this family, while normal levels were found among obligate carriers. Through in vitro functional assays, we showed that this mutation decreases cellular T3 uptake and intracellular T3 metabolism. Therefore, the severe neurological defects present in the patients are due not only to deficiency of intracellular T3, but also to altered metabolism of T3 in central neurones. In addition, the severe muscle hypoplasia observed in most AHDS patients may be a consequence of high serum T3 levels.

Asunto(s)

Mutación del Sistema de Lectura , Enfermedades Genéticas Ligadas al Cromosoma X/genética , Discapacidad Intelectual/genética , Transportadores de Ácidos Monocarboxílicos/genética , Enfermedades del Sistema Nervioso/genética , Triyodotironina/metabolismo , Adulto , Anciano , Transporte Biológico , Análisis Mutacional de ADN , Femenino , Enfermedades Genéticas Ligadas al Cromosoma X/diagnóstico , Pruebas Genéticas , Humanos , Discapacidad Intelectual/diagnóstico , Masculino , Persona de Mediana Edad , Enfermedades del Sistema Nervioso/diagnóstico , Linaje , Eliminación de Secuencia , Simportadores , Síndrome , Hormonas Tiroideas/sangre , Triyodotironina/sangre

RESUMEN

Trigonocephaly is a rare form of craniosynostosis characterized by the premature closure of the metopic suture. To contribute to a better understanding of the genetic basis of metopic synostosis and in an attempt to restrict the candidate regions related to metopic suture fusion, we studied 76 unrelated patients with syndromic and non-syndromic trigonocephaly. We found a larger proportion of syndromic cases in our population and the ratio of affected male to female was 1.8 : 1 and 5 : 1 in the non-syndromic and syndromic groups, respectively. A microdeletion screening at 9p22-p24 and 11q23-q24 was carried out for all patients and deletions in seven of them were detected, corresponding to 19.4% of all syndromic cases. Deletions were not found in non-syndromic patients. We suggest that a molecular screening for microdeletions at 9p22-p24 and 11q23-q24 should be offered to all syndromic cases with an apparently normal karyotype because it can potentially elucidate the cause of trigonocephaly in this subset of patients. We also suggest that genes on the X-chromosome play a major role in syndromic trigonocephaly.

Asunto(s)

Deleción Cromosómica , Cromosomas Humanos Par 11 , Cromosomas Humanos Par 9 , Craneosinostosis/genética , Pruebas Genéticas/métodos , Niño , Preescolar , Estudios de Cohortes , Craneosinostosis/diagnóstico , Femenino , Humanos , Lactante , Cariotipificación , Masculino , Linaje , Fenotipo