RESUMO
The Spontaneously Hypertensive Rat (SHR) has been proposed as a good model to study the pathways related to neurodegenerative diseases and glucose intolerance. Our research group developed the SLA16 (SHR.LEW-Anxrr16) congenic strain, which is genetically identical to the SHR strain, except for a locus on chromosome 4 (DGR). We applied in silico analysis on DGR to evaluate the association of their genes with neurobiological and metabolic pathways. After, we characterized cholesterol, triglycerides, metabolism of glucose and the behavioral performance of young (2 months old) and adult (8 months old) SHR and SLA16 rats in the open field, object location and water maze tasks. Finally, naïve young rats were repeatedly treated with metformin (200 mg/kg; v.o.) and evaluated in the same tests. Bioinformatics analysis showed that DGR presents genes related to glucose metabolism, oxidative damage and neurodegenerative diseases. Young SLA16 presented higher cholesterol, triglycerides, glucose and locomotion in the open field than SHR rats. In adulthood, SLA16 rats presented high triglycerides and locomotion in the open field and impairment on spatial learning and memory. Finally, the treatment with metformin decreased the glucose tolerance curve and also improved long-term memory in SLA16 rats. These results indicate that DGR presents genes associated with metabolic pathways and neurobiological processes that may produce alterations in glucose metabolism and spatial learning/memory. Therefore, we suggest that SHR and SLA16 strains could be important for the study of genes and subsequent mechanisms that produce metabolic glucose alterations and age-related cognitive deficits.
Assuntos
Ratos Endogâmicos SHR/genética , Memória Espacial/fisiologia , Animais , Comportamento Animal , Cromossomos Humanos Par 4/genética , Cromossomos de Mamíferos/genética , Transtornos Cognitivos/fisiopatologia , Modelos Animais de Doenças , Genoma/genética , Humanos , Hipertensão/genética , Hipertensão/fisiopatologia , Masculino , Doenças Metabólicas/genética , Ratos/genéticaRESUMO
BACKGROUND: Since 1969, 49 cases have been presented on ring chromosome 4. All of these cases have been characterized for the loss of genetic material. The genes located in these chromosomal regions are related to the phenotype. CASE PRESENTATION: A 10-year-old Ecuadorian Mestizo girl with ring chromosome 4 was clinically, cytogenetically and molecularly analysed. Clinical examination revealed congenital anomalies, including microcephaly, prominent nose, micrognathia, low set ears, bilateral clinodactyly of the fifth finger, small sacrococcygeal dimple, short stature and mental retardation. Cytogenetic studies showed a mosaic karyotype, mos 46,XX,r(4)(p16.3q35.2)/46,XX, with a ring chromosome 4 from 75 to 79% in three studies conducted over ten years. These results were confirmed by fluorescence in situ hybridization (FISH). Loss of 1.7 Mb and gain of 342 kb in 4p16.3 and loss of 3 Mb in 4q35.2 were identified by high-resolution mapping array. CONCLUSION: Most cases with ring chromosome 4 have deletion of genetic material in terminal regions; however, our case has inv dup del rearrangement in the ring chromosome formation. Heterogeneous clinical features in all cases reviewed are related to the amount of genetic material lost or gained. The application of several techniques can increase our knowledge of ring chromosome 4 and its deviations from typical "ring syndrome."
Assuntos
Transtornos Cromossômicos/genética , Transtornos Cromossômicos/patologia , Criança , Cromossomos Humanos Par 4/genética , Análise Citogenética , Feminino , Humanos , Hibridização in Situ Fluorescente , Cariotipagem , Cromossomos em AnelRESUMO
Deletions in the 4p16.3 region are associated with Wolf-Hirschhorn syndrome (WHS), a contiguous gene deletion syndrome involving variable size deletions. In this study, we perform a cytogenomic integrative analysis combining classical cytogenetic methods, fluorescence in situ hybridization (FISH), chromosomal microarray analysis (CMA), and systems biology strategies, to establish the cytogenomic profile involving the 4p16.3 critical region and suggest WHS-related intracellular cell signaling cascades. The cytogenetic and clinical patient profiles were evaluated. We characterized 12 terminal deletions, one interstitial deletion, two ring chromosomes, and one classical translocation 4;8. CMA allowed delineation of the deletions, which ranged from 3.7 to 25.6 Mb with breakpoints from 4p16.3 to 4p15.33. Furthermore, the smallest region of overlapping (SRO) encompassed seven genes in a terminal region of 330 kb in the 4p16.3 region, suggesting a region of susceptibility to convulsions and microcephaly. Therefore, molecular interaction networks and topological analysis were performed to understand these WHS-related symptoms. Our results suggest that specific cell signaling pathways including dopamine receptor, NAD+ nucleosidase activity, and fibroblast growth factor-activated receptor activity are associated with the diverse pathological WHS phenotypes and their symptoms. Additionally, we identified 29 hub-bottlenecks (H-B) nodes with a major role in WHS.
Assuntos
Deleção Cromossômica , Coloração Cromossômica , Cromossomos Humanos Par 4/genética , Redes Reguladoras de Genes , Síndrome de Wolf-Hirschhorn/genética , Feminino , Humanos , Masculino , Estudos RetrospectivosRESUMO
It has been proposed that copy number variations (CNVs) are associated with increased risk of autism spectrum disorder (ASD) and, in conjunction with other genetic changes, contribute to the heterogeneity of ASD phenotypes. Array comparative genomic hybridization (aCGH) and exome sequencing, together with systems genetics and network analyses, are being used as tools for the study of complex disorders of unknown etiology, especially those characterized by significant genetic and phenotypic heterogeneity. Therefore, to characterize the complex genotype-phenotype relationship, we performed aCGH and sequenced the exomes of two affected siblings with ASD symptoms, dysmorphic features, and intellectual disability, searching for de novo CNVs, as well as for de novo and rare inherited point variations-single nucleotide variants (SNVs) or small insertions and deletions (indels)-with probable functional impacts. With aCGH, we identified, in both siblings, a duplication in the 4p16.3 region and a deletion at 8p23.3, inherited by a paternal balanced translocation, t(4, 8) (p16; p23). Exome variant analysis found a total of 316 variants, of which 102 were shared by both siblings, 128 were in the male sibling exome data, and 86 were in the female exome data. Our integrative network analysis showed that the siblings' shared translocation could explain their similar syndromic phenotype, including overgrowth, macrocephaly, and intellectual disability. However, exome data aggregate genes to those already connected from their translocation, which are important to the robustness of the network and contribute to the understanding of the broader spectrum of psychiatric symptoms. This study shows the importance of using an integrative approach to explore genotype-phenotype variability.
Assuntos
Transtorno do Espectro Autista/genética , Cromossomos Humanos Par 4/genética , Cromossomos Humanos Par 8/genética , Hibridização Genômica Comparativa , Variações do Número de Cópias de DNA , Exoma/genética , Estudos de Associação Genética , Translocação Genética , Criança , Cromossomos Humanos Par 4/ultraestrutura , Cromossomos Humanos Par 8/ultraestrutura , Feminino , Duplicação Gênica , Redes Reguladoras de Genes , Humanos , Hibridização in Situ Fluorescente , Deficiência Intelectual/genética , Deficiências da Aprendizagem/genética , Masculino , Megalencefalia/genética , Proteínas do Tecido Nervoso/genética , Técnicas de Amplificação de Ácido Nucleico , Deleção de Sequência , Irmãos , SíndromeRESUMO
Cytogenetic analysis remains a powerful and cost-effective technology, and has wide applicability in genetic counseling for infertile males. Chromosomal rearrangements are thought to be one of the major genetic factors that influence male infertility. Some carriers with balanced reciprocal translocation have been identified as having oligozoospermia or azoospermia, and there is an association between balanced translocation and recurrent abortion. Researchers have reported the involvement of chromosome 4 translocations in male factor infertility and recurrent miscarriages. A translocation breakpoint might interrupt the structure of an important gene, and it is associated with reproductive failure. However, the clinical characteristics of the breakpoints in chromosome 4 translocations have not been studied. Here, we report the breakpoints in chromosome 4 translocation and the clinical features presented in carriers to enable informed genetic counseling of these patients. Of 82 patients with balanced reciprocal translocations, 14 were carriers of the chromosome 4 translocation: four presented with pregestational infertility (clinical manifestations: oligozoospermia, severe oligozoospermia, or azoospermia), whereas 10 presented with gestational infertility (able to conceive but with a tendency to miscarry). The breakpoint at 4q12 was associated with pregestational infertility, whereas the breakpoints at 4q13, 4q21, 4q25, and 4q32 were associated with gestational infertility. However, the breakpoint at 4q35 was associated with both pregestational and gestational infertility. Chromosome 4 translocation carriers with pregestational or gestational infertility should be counseled on chromosomal breakpoints and the different technologies available to assist reproduction.
Assuntos
Aborto Espontâneo/genética , Azoospermia/genética , Pontos de Quebra do Cromossomo , Cromossomos Humanos Par 4/genética , Oligospermia/genética , Feminino , Aconselhamento Genético , Heterozigoto , Humanos , Masculino , Gravidez , Translocação GenéticaRESUMO
Wolf-Hirschhorn syndrome (WHS) is a contiguous gene and multiple malformation syndrome that results from a deletion in the 4p16.3 region. We describe here a 6-month-old girl that presented with WHS features but also displayed unusual findings, such as epibulbar dermoid in the left eye, ear tags, and left microtia. Although on G-banding her karyotype appeared to be normal, chromosomal microarray analysis revealed an â¼13-Mb 4p16.3p15.33 deletion and an â¼9-Mb Xp22.33p22.31 duplication, resulting from a balanced maternal t(X;4)(p22.31;p15.33) translocation. The patient presented with functional Xp disomy due to an unbalanced X-autosome translocation, a rare cytogenetic finding in females with unbalanced rearrangements. Sequencing of both chromosome breakpoints detected no gene disruption. To the best of our knowledge, this is the first patient described in the literature with WHS and epibulbar dermoid, a typical characteristic of the oculoauriculovertebral spectrum (OAVS). Our data suggest that possible candidate genes for OAVS may have been deleted along with the WHS critical region.
Assuntos
Deleção Cromossômica , Duplicação Cromossômica/genética , Cromossomos Humanos Par 4/genética , Cromossomos Humanos X/genética , Cisto Dermoide/genética , Translocação Genética/genética , Síndrome de Wolf-Hirschhorn/genética , Adulto , Criança , Bandeamento Cromossômico , Pontos de Quebra do Cromossomo , Feminino , Humanos , Lactente , Idade MaternaRESUMO
The most prevalent structural variations in the human genome are copy number variations (CNVs), which appear predominantly in the subtelomeric regions. Variable sizes of 4p/4q CNVs have been associated with several different psychiatric findings and developmental disability (DD). We analyzed 105 patients with congenital anomalies (CA) and developmental and/or intellectual disabilities (DD/ID) using MLPA subtelomeric specific kits (P036 /P070) and 4 of them using microarrays. We found abnormal subtelomeric CNVs in 15 patients (14.3%), including 8 patients with subtelomeric deletions at 4p/4q (53.3%). Additional genomic changes were observed at 1p36, 2q37.3, 5p15.3, 5q35.3, 8p23.3, 13q11, 14q32.3, 15q11.2, and Xq28/Yq12. This indicates the prevalence of independent deletions at 4p/4q, involving PIGG, TRIML2, and FRG1. Furthermore, we identified 15 genes with changes in copy number that contribute to neurological development and/or function, among them CRMP1, SORCS2, SLC25A4, and HELT. Our results highlight the association of genes with changes in copy number at 4p and 4q subtelomeric regions and the DD phenotype. Cytogenomic characterization of additional cases with distal deletions should help clarifying the role of subtelomeric CNVs in neurological diseases.
Assuntos
Transtornos Cromossômicos/genética , Variações do Número de Cópias de DNA/genética , Deficiências do Desenvolvimento/genética , Deleção Cromossômica , Cromossomos Humanos Par 4/genética , Feminino , Deleção de Genes , Humanos , Masculino , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Telômero/genéticaRESUMO
BACKGROUND: Facioscapulohumeral muscular dystrophy is the third most common muscular dystrophy with an estimated prevalence of 1 per 20.000 and a normal life expectancy in the majority of patients. However, approximately 15% of patients become wheelchair bound in the course of their life. It is a hereditary autosomal dominant disease with high (95%) penetrance by the age of 20, but with variable degree of phenotypic expression even in the same family group. Symptoms frequently start in the second decade of life, with facial and scapular weakness. AIM: To report the clinical features of seven patients with the disease, seen at a public hospital. MATERIAL AND METHODS: Analysis of seven patients with genetic study seen in a public Hospital in Santiago. RESULTS: The age of patients fluctuated from 18 to 61 years and four were females. The mean age at onset of symptoms was 29 years and four had a family history of the disease. The usual presenting complaint was arm or shoulder asymmetric weakness. Four patients had bone pain. Facial involvement was present in four. A genetic study was done in five patients, the other two patients were relatives, confirming the contraction or lower number of repetitions in D4Z4 region. After 12 years of follow up only 2 patients older than 60 years cannot work and one female patients is in a semi dependent state at the age of 30. CONCLUSIONS: The clinical workup in the diagnosis and the timely indication of genetic studies are highlighted, to avoid unnecessary and invasive procedures. The variability in the phenotypic expression in a similar genetic defect is discussed and the genetic or epigenetic mechanisms of this muscular dystrophy are described.
Assuntos
Cromossomos Humanos Par 4/genética , Distrofia Muscular Facioescapuloumeral/genética , Fenótipo , Adolescente , Adulto , Biópsia , Creatina Quinase/sangue , Diagnóstico Diferencial , Eletromiografia , Assimetria Facial/etiologia , Feminino , Seguimentos , Predisposição Genética para Doença , Humanos , Masculino , Pessoa de Meia-Idade , Debilidade Muscular/etiologia , Distrofia Muscular Facioescapuloumeral/complicações , Distrofia Muscular Facioescapuloumeral/diagnóstico , Distrofia Muscular Facioescapuloumeral/patologia , Mutação/genética , Dor de Ombro/etiologia , Centros de Atenção Terciária , Adulto JovemRESUMO
PURPOSE: To present the results of the clinical and molecular analyses of a familial case of Wolfram Syndrome (WFS) associated with a novel ocular anomaly. METHODS: Full ophthalmologic examination was performed in two WFS siblings. Visante OCT imaging was used for assessing anterior segment anomalies. Genetic analysis included PCR amplification and exon-by-exon nucleotide sequencing of the WFS1 gene. RESULTS: Ocular anomalies in both affected siblings included congenital cataract, glaucoma, and optic atrophy. Interestingly, microspherophakia, a feature that has not been previously associated with WFS, was observed in both siblings. Genetic analysis disclosed a novel c.1525_1539 homozygous deletion in exon 8 of WFS1 in DNA from both affected patients. CONCLUSIONS: The recognition of microspherophakia in two siblings carrying a novel WFS1 mutation expands the clinical and molecular spectrum of Wolfram syndrome.
Assuntos
Cromossomos Humanos Par 4/genética , Anormalidades do Olho/genética , Cristalino/anormalidades , Proteínas de Membrana/genética , Deleção de Sequência , Síndrome de Wolfram/genética , Adolescente , Sequência de Bases , Éxons/genética , Anormalidades do Olho/diagnóstico , Feminino , Humanos , Dados de Sequência Molecular , Linhagem , Reação em Cadeia da Polimerase , Irmãos , Tomografia de Coerência Óptica , Síndrome de Wolfram/diagnóstico , Adulto JovemRESUMO
We report a patient with a maternally inherited unbalanced complex chromosomal rearrangement (CCR) involving chromosomes 4, 9, and 11 detected by microarray comparative genomic hybridization (aCGH) and fluorescence in situ hybridization (FISH). This patient presents with clinical features of 9p deletion syndrome and Silver-Russell syndrome (SRS). Chromosome analysis performed in 2000 showed what appeared to be a simple terminal deletion of chromosome 9p22.1. aCGH performed in 2010 revealed a 1.63 Mb duplication at 4q28.3, a 15.48 Mb deletion at 9p24.3p22.3, and a 1.95 Mb duplication at 11p15.5. FISH analysis revealed a derivative chromosome 9 resulting from an unbalanced translocation between chromosomes 9 and 11, a chromosome 4 fragment inserted near the breakpoint of the translocation. The 4q28.3 duplication does not contain any currently known genes. The 9p24.3p22.3 deletion region contains 36 OMIM genes including a 3.5 Mb critical region for the 9p-phenotype. The 11p15.5 duplication contains 49 OMIM genes including H19 and IGF2. Maternal aCGH was normal. However, maternal chromosomal and FISH analyses revealed an apparently balanced CCR involving chromosomes 4, 9, and 11. To the best of our knowledge, this is the first report of a patient with maternally inherited trans-duplication of the entire imprinting control region 1 (ICR1) among the 11p15.5 duplications reported in SRS patients. This report supports the hypothesis that the trans-duplication of the maternal copy of ICR1 alone is sufficient for the clinical manifestation of SRS and demonstrates the usefulness of combining aCGH with karyotyping and FISH for detecting cryptic genomic imbalances.