El Trastorno del Espectro Autista (TEA) es una alteración del neurodesarollo que afecta las áreas... more El Trastorno del Espectro Autista (TEA) es una alteración del neurodesarollo que afecta las áreas de comunicación social y conducta, las cuales se manifiestan de manera heterogénea en cada niño y con una amplia gama de niveles de funcionalidad. En la última década se han hecho avances significativos en la detección temprana de señales de riesgo, favoreciendo la realización de diagnósticos precoz. Esto ha permitido el acceso a intervenciones que capitalizan la neuroplasticidad de esta etapa del desarrollo, planteando la posibilidad de mitigar la completa manifestación del trastorno. Los objetivos de esta actualización son revisar herramientas de diagnóstico precoz y modelos de intervención temprana, y analizar cómo implementar intervenciones basadas en la evidencia en un contexto sanitario de un país como Chile.
Purpose: To examine the association between age-related changes in the T-cell compartment and pre... more Purpose: To examine the association between age-related changes in the T-cell compartment and prevalence of age-related macular degeneration (AMD).
Age-related macular degeneration (AMD) is a multifactorial disease and a prevalent cause of visua... more Age-related macular degeneration (AMD) is a multifactorial disease and a prevalent cause of visual impairment in developed countries. Risk factors include environmental components and genetic determinants. The complement factor H (CFH) has been the first major susceptibility gene for AMD identified within 1q32. Here, we focused on a second region of interest in 10q26 where a recent meta-analysis revealed strongest evidence for linkage to AMD at a genome-wide significance level. Within an interval of 22 Mb, we have analyzed 93 single nucleotide polymorphisms for allelic association with AMD in two independent case-control cohorts of German origin (AMD combined n 5 1166; controls combined n 5 945). Significant association was found across a 60 kb region of high linkage disequilibrium harboring two genes PLEKHA1 and hypothetical LOC387715. The strongest association (P 5 10 234 ) centered over a frequent coding polymorphism, Ala69Ser, at LOC387715, strongly implicating this gene in the pathogenesis of AMD. Besides abundant expression in placenta, we demonstrate weak expression of LOC387715 in the human retina. At present, however, there is no functional information on this gene, which appears to have evolved recently within the primate lineage. The joint contribution of the common risk allele at LOC387715, Ala69Ser, and at CFH, Tyr402His, was assessed in our case-control population, which suggests an additive model indicating an independent contribution of the two gene loci to disease risk. Our data show a disease odds ratio of 57.6 (95% CI: 37.2, 89.0) conferred by homozygosity for risk alleles at both CFH and LOC387715 when compared with the baseline non-risk genotype.
Recently, the VMD2 gene has been identified as the causative gene in juvenile-onset vitelliform m... more Recently, the VMD2 gene has been identified as the causative gene in juvenile-onset vitelliform macular dystrophy (Best disease), a central retinopathy primarily characterised by an impaired function of the retinal pigment epithelium. In this study we have further characterised the spectrum of VMD2 mutations in a series of 41 unrelated Best disease patients. Furthermore we expanded our analysis to include 32 unrelated patients with adult vitelliform macular dystrophy (AVMD) and 200 patients with age-related macular degeneration (AMD). Both AVMD and AMD share some phenotypic features with Best disease such as abnormal subretinal accumulation of lipofuscin material, progressive geographic atrophy and choroidal neovascularisation, and may be the consequence of a common pathogenic mechanism. In total, we have identified 23 distinct disease-associated mutations in Best disease and four different mutations in AVMD. Two of the mutations found in the AVMD patients were also seen in Best disease suggesting a considerable overlap in the aetiology of these two disorders. There were no mutations found in the AMD group. In addition, four frequent intragenic polymorphisms did not reveal allelic association of the VMD2 locus with AMD. These data exclude a direct role of VMD2 in the predisposition to AMD.
Vitelliform macular dystrophy (Best's disease) is an autosomal dominant, early-onset form of macu... more Vitelliform macular dystrophy (Best's disease) is an autosomal dominant, early-onset form of macular degeneration in which the primary defect is thought to occur at the level of the retinal pigment epithelium. Genetic linkage has mapped the disease locus to chromosome 11q12-q13.1 within a 980 kb interval flanked by markers at loci D11S4076 and uteroglobin. To identify the disease gene, we systematically characterized genes from within the critical region and analysed the coding regions for mutations in 12 patients from large multigeneration Best's disease families. Following this approach, we identified a novel gene of unknown function carrying heterozygous mutations in all 12 probands. Of these, 10 result in distinct missense mutations of amino acids that are highly conserved throughout evolution, spanning a phylogenetic distance from Caenorhabditis elegans to human, and include V9M, A10T, W24C, R25Q, R218Q, Y227N, Y227C, V235M, P297A and F305S. One deletion mutation, ∆I295, was found in two families and segregates with the disease in both cases. Northern blot analysis reveals tissue-specific expression for this gene, exclusively in the retinal pigment epithelium. In conclusion, our data provide strong evidence that mutations in the gene that we have identified cause Best's disease.
Best's vitelliform macular dystrophy (Best's dise... more Best's vitelliform macular dystrophy (Best's disease) is an autosomal dominant disorder of unknown causes and is typically characterised by an accumulation of lipofuscin-like material in the subretinal space of the macula. The disease gene has been localised to chromosome 11q12-13.1 within a 1.4 Mbp interval flanked by markers at D11S1765 and uteroglobin (UGB). Here we report the refined mapping of the gene encoding the p127 kDa subunit (DDB1) of a UV damage-specific DNA binding protein within the D11S1765-UGB region. Northern blot analysis demonstrates an abundant expression of the DDB1 transcript in the retina suggesting a functional role for DDB1 in this tissue. These considerations together with the chromosomal localisation have led us to evaluate the possible involvement of DDB1 in the pathogenesis of Best's disease.
Stargardt disease (STGD) is a common autosomal recessive maculopathy of early and young-adult ons... more Stargardt disease (STGD) is a common autosomal recessive maculopathy of early and young-adult onset and is caused by alterations in the gene encoding the photoreceptor-specific ATP-binding cassette (ABC) transporter (ABCA4). We have studied 144 patients with STGD and 220 unaffected individuals ascertained from the German population, to complete a comprehensive, population-specific survey of the sequence variation in the ABCA4 gene. In addition, we have assessed the proposed role for ABCA4 in age-related macular degeneration (AMD), a common cause of late-onset blindness, by studying 200 affected individuals with late-stage disease. Using a screening strategy based primarily on denaturing gradient gel electrophoresis, we have identified in the three study groups a total of 127 unique alterations, of which 90 have not been previously reported, and have classified 72 as probable pathogenic mutations. Of the 288 STGD chromosomes studied, mutations were identified in 166, resulting in a detection rate of ∼58%. Eight different alleles account for 61% of the identified disease alleles, and at least one of these, the L541P-A1038V complex allele, appears to be a founder mutation in the German population. When the group with AMD and the control group were analyzed with the same methodology, 18 patients with AMD and 12 controls were found to harbor possible disease-associated alterations. This represents no significant difference between the two groups; however, for detection of modest effects of rare alleles in complex diseases, the analysis of larger cohorts of patients may be required.
Demonstrating the types of ABCA4 mutations in the STGD1 gene in a family manifesting both Stargar... more Demonstrating the types of ABCA4 mutations in the STGD1 gene in a family manifesting both Stargardt's disease and retinitis pigmentosa (RP19). Clinical ophthalmological examination included funduscopy, ERG, Arden Colour contrast test, fluorescein angiography in one patient, perimetry and SLO perimetry. The 50 exons of the ABCA4 gene were screened using a combination of denaturating gradient gel electrophoresis (DGGE), high performance electrophoresis (dHPLC) and SSCP analysis. Patient I/1 showed typical signs of Stargardt's disease, while her son, II-1 demonstrated functional signs and morphological features of retinitis pigmentosa. Mutational analysis of the ABCA4 gene revealed a missense mutation in exon 42 (G5882G > A) and a frameshift mutation in exon 43 (5917delG) of patient I-1. Patient II/1 demonstrated a homozygous 5917delG mutation in exon 43, resulting in a functional null-mutation. The combination of ABCA4 alleles with various functional consequences to protein activity can lead to different clinical phenotypes in one and the same family, resulting either in typical Stargardt's disease or in autosomal recessive retinitis pigmentosa (RP19).
El Trastorno del Espectro Autista (TEA) es una alteración del neurodesarollo que afecta las áreas... more El Trastorno del Espectro Autista (TEA) es una alteración del neurodesarollo que afecta las áreas de comunicación social y conducta, las cuales se manifiestan de manera heterogénea en cada niño y con una amplia gama de niveles de funcionalidad. En la última década se han hecho avances significativos en la detección temprana de señales de riesgo, favoreciendo la realización de diagnósticos precoz. Esto ha permitido el acceso a intervenciones que capitalizan la neuroplasticidad de esta etapa del desarrollo, planteando la posibilidad de mitigar la completa manifestación del trastorno. Los objetivos de esta actualización son revisar herramientas de diagnóstico precoz y modelos de intervención temprana, y analizar cómo implementar intervenciones basadas en la evidencia en un contexto sanitario de un país como Chile.
Purpose: To examine the association between age-related changes in the T-cell compartment and pre... more Purpose: To examine the association between age-related changes in the T-cell compartment and prevalence of age-related macular degeneration (AMD).
Age-related macular degeneration (AMD) is a multifactorial disease and a prevalent cause of visua... more Age-related macular degeneration (AMD) is a multifactorial disease and a prevalent cause of visual impairment in developed countries. Risk factors include environmental components and genetic determinants. The complement factor H (CFH) has been the first major susceptibility gene for AMD identified within 1q32. Here, we focused on a second region of interest in 10q26 where a recent meta-analysis revealed strongest evidence for linkage to AMD at a genome-wide significance level. Within an interval of 22 Mb, we have analyzed 93 single nucleotide polymorphisms for allelic association with AMD in two independent case-control cohorts of German origin (AMD combined n 5 1166; controls combined n 5 945). Significant association was found across a 60 kb region of high linkage disequilibrium harboring two genes PLEKHA1 and hypothetical LOC387715. The strongest association (P 5 10 234 ) centered over a frequent coding polymorphism, Ala69Ser, at LOC387715, strongly implicating this gene in the pathogenesis of AMD. Besides abundant expression in placenta, we demonstrate weak expression of LOC387715 in the human retina. At present, however, there is no functional information on this gene, which appears to have evolved recently within the primate lineage. The joint contribution of the common risk allele at LOC387715, Ala69Ser, and at CFH, Tyr402His, was assessed in our case-control population, which suggests an additive model indicating an independent contribution of the two gene loci to disease risk. Our data show a disease odds ratio of 57.6 (95% CI: 37.2, 89.0) conferred by homozygosity for risk alleles at both CFH and LOC387715 when compared with the baseline non-risk genotype.
Recently, the VMD2 gene has been identified as the causative gene in juvenile-onset vitelliform m... more Recently, the VMD2 gene has been identified as the causative gene in juvenile-onset vitelliform macular dystrophy (Best disease), a central retinopathy primarily characterised by an impaired function of the retinal pigment epithelium. In this study we have further characterised the spectrum of VMD2 mutations in a series of 41 unrelated Best disease patients. Furthermore we expanded our analysis to include 32 unrelated patients with adult vitelliform macular dystrophy (AVMD) and 200 patients with age-related macular degeneration (AMD). Both AVMD and AMD share some phenotypic features with Best disease such as abnormal subretinal accumulation of lipofuscin material, progressive geographic atrophy and choroidal neovascularisation, and may be the consequence of a common pathogenic mechanism. In total, we have identified 23 distinct disease-associated mutations in Best disease and four different mutations in AVMD. Two of the mutations found in the AVMD patients were also seen in Best disease suggesting a considerable overlap in the aetiology of these two disorders. There were no mutations found in the AMD group. In addition, four frequent intragenic polymorphisms did not reveal allelic association of the VMD2 locus with AMD. These data exclude a direct role of VMD2 in the predisposition to AMD.
Vitelliform macular dystrophy (Best's disease) is an autosomal dominant, early-onset form of macu... more Vitelliform macular dystrophy (Best's disease) is an autosomal dominant, early-onset form of macular degeneration in which the primary defect is thought to occur at the level of the retinal pigment epithelium. Genetic linkage has mapped the disease locus to chromosome 11q12-q13.1 within a 980 kb interval flanked by markers at loci D11S4076 and uteroglobin. To identify the disease gene, we systematically characterized genes from within the critical region and analysed the coding regions for mutations in 12 patients from large multigeneration Best's disease families. Following this approach, we identified a novel gene of unknown function carrying heterozygous mutations in all 12 probands. Of these, 10 result in distinct missense mutations of amino acids that are highly conserved throughout evolution, spanning a phylogenetic distance from Caenorhabditis elegans to human, and include V9M, A10T, W24C, R25Q, R218Q, Y227N, Y227C, V235M, P297A and F305S. One deletion mutation, ∆I295, was found in two families and segregates with the disease in both cases. Northern blot analysis reveals tissue-specific expression for this gene, exclusively in the retinal pigment epithelium. In conclusion, our data provide strong evidence that mutations in the gene that we have identified cause Best's disease.
Best's vitelliform macular dystrophy (Best's dise... more Best's vitelliform macular dystrophy (Best's disease) is an autosomal dominant disorder of unknown causes and is typically characterised by an accumulation of lipofuscin-like material in the subretinal space of the macula. The disease gene has been localised to chromosome 11q12-13.1 within a 1.4 Mbp interval flanked by markers at D11S1765 and uteroglobin (UGB). Here we report the refined mapping of the gene encoding the p127 kDa subunit (DDB1) of a UV damage-specific DNA binding protein within the D11S1765-UGB region. Northern blot analysis demonstrates an abundant expression of the DDB1 transcript in the retina suggesting a functional role for DDB1 in this tissue. These considerations together with the chromosomal localisation have led us to evaluate the possible involvement of DDB1 in the pathogenesis of Best's disease.
Stargardt disease (STGD) is a common autosomal recessive maculopathy of early and young-adult ons... more Stargardt disease (STGD) is a common autosomal recessive maculopathy of early and young-adult onset and is caused by alterations in the gene encoding the photoreceptor-specific ATP-binding cassette (ABC) transporter (ABCA4). We have studied 144 patients with STGD and 220 unaffected individuals ascertained from the German population, to complete a comprehensive, population-specific survey of the sequence variation in the ABCA4 gene. In addition, we have assessed the proposed role for ABCA4 in age-related macular degeneration (AMD), a common cause of late-onset blindness, by studying 200 affected individuals with late-stage disease. Using a screening strategy based primarily on denaturing gradient gel electrophoresis, we have identified in the three study groups a total of 127 unique alterations, of which 90 have not been previously reported, and have classified 72 as probable pathogenic mutations. Of the 288 STGD chromosomes studied, mutations were identified in 166, resulting in a detection rate of ∼58%. Eight different alleles account for 61% of the identified disease alleles, and at least one of these, the L541P-A1038V complex allele, appears to be a founder mutation in the German population. When the group with AMD and the control group were analyzed with the same methodology, 18 patients with AMD and 12 controls were found to harbor possible disease-associated alterations. This represents no significant difference between the two groups; however, for detection of modest effects of rare alleles in complex diseases, the analysis of larger cohorts of patients may be required.
Demonstrating the types of ABCA4 mutations in the STGD1 gene in a family manifesting both Stargar... more Demonstrating the types of ABCA4 mutations in the STGD1 gene in a family manifesting both Stargardt's disease and retinitis pigmentosa (RP19). Clinical ophthalmological examination included funduscopy, ERG, Arden Colour contrast test, fluorescein angiography in one patient, perimetry and SLO perimetry. The 50 exons of the ABCA4 gene were screened using a combination of denaturating gradient gel electrophoresis (DGGE), high performance electrophoresis (dHPLC) and SSCP analysis. Patient I/1 showed typical signs of Stargardt's disease, while her son, II-1 demonstrated functional signs and morphological features of retinitis pigmentosa. Mutational analysis of the ABCA4 gene revealed a missense mutation in exon 42 (G5882G > A) and a frameshift mutation in exon 43 (5917delG) of patient I-1. Patient II/1 demonstrated a homozygous 5917delG mutation in exon 43, resulting in a functional null-mutation. The combination of ABCA4 alleles with various functional consequences to protein activity can lead to different clinical phenotypes in one and the same family, resulting either in typical Stargardt's disease or in autosomal recessive retinitis pigmentosa (RP19).
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