16 research outputs found
Worldwide survey of the deltaF508 mutation-report from the Cystic Fibrosis Genetic Analysis Consortium
No full textGenetic Landscape of Slovenians: Past Admixture and Natural Selection Pattern
No full textThe Slovenian territory played a crucial role in the past serving as gateway for several human migrations. Previous studies used Slovenians as a source population to interpret different demographic events happened in Europe but not much is known about the genetic background and the demographic history of this population. Here, we analyzed genome-wide data from 96 individuals to shed light on the genetic role and history of the Slovenian population. Y chromosome diversity splits into two major haplogroups R1b and R1a with the latter suggesting a genetic contribution from the steppe. Slovenian individuals are more closely related to Northern and Eastern European populations than Southern European populations even though they are geographically closer. This pattern is confirmed by an admixture and clustering analysis. We also identified a single stream of admixture events between the Slovenians with Sardinians and Russians around ∼2630 BCE (2149-3112). Using ancient samples, we found a significant admixture in Slovenians using Yamnaya and the early Neolithic Hungarians as sources, dated around ∼1762 BCE (1099-2426) suggesting a strong contribution from the steppe to the foundation of the observed modern genetic diversity. Finally, we looked for signals of selection in candidate variants and we found significant hits in HERC2 and FADS responsible for blue eye color and synthesis of long-chain unsaturated fatty acids, respectively, when Slovenians were compared to Southern Europeans. While the comparison was done with Eastern Europeans, we identified significant signals in PKD2L1 and IL6R which are genes associated with taste and coronary artery disease, respectively
"Cystic Fibrosis gene mutations and linked RFLPs in the Slovenian population"
No full textThe authors used polymerase chain reaction to analyse 56 Slovenian cystic fibrosis (CF) chromosomes for the presence of delta F508 and eight other most frequent mutations located in exons 7,11 and 20 (R347P, R334W, G551D, R553X, S549RA, S549RT, S549I and S1255X) of the CF gene. We also determined the frequency of haplotypes associated with CF for six linked RFLP markers (MetD/TaqI, MetH/TaqI, XV-2c/TaqI, KM-19/PstI, MP6d9/MspI and J3.11/MspI) in 27 Slovenian CF families. delta F508 mutation was present in 55.4 percent of the CF chromosomes. No case of the other mutations were detected in the sample of tested CF chromosomes. A very high degree of association (0.88) has been found between DNA marker MetH and CF (as measured by the Yule's association coefficient) in our population. Using the RFLP markers XV-2c and KM-19, we found that 85% of delta F508 mutated chromosomes have a single 1 2 (B) haplotype, and that this haplotype is present on only 15.4 percent of CF chromosomes without this deletion
"Analysis of 14 cystic fibrosis mutations in five South European populations"
No full textWe have analysed five Southern European populations (Albanian, Greek, Italian, Spanish and Yugoslavian) for 14 cystic fibrosis (CF) mutations. The most frequent mutations, apart from delta F508, were G542X (6.04%), R1162X (3.61%) and N1303K (3.24%). Each of the other analysed mutations were present at a frequency of less than 1% (R347P, R334W, S549RA, S549I, G551D, R553X and W1282X), and four mutations (D110H, delta I507, S549RT, and S1255X) were not found in this sample. The data presented here allows the use of mutation analysis in 69.5% of Spanish, 58% of Greek, and 56.5% of Italian CF cases
Genotyping microarray (gene chip) for the ABCR (ABCA4) gene
No full textGenetic variation in the ABCR (ABCA4) gene has been associated with five distinct retinal phenotypes, including Stargardt disease/fundus flavimaculatus (STGD/FFM), cone-rod dystrophy (CRD), and age-related macular degeneration (AMD). Comparative genetic analyses of ABCR variation and diagnostics have been complicated by substantial allelic heterogeneity and by differences in screening methods. To overcome these limitations, we designed a genotyping microarray (gene chip) for ABCR that includes all ∼-400 disease-associated and other variants currently described, enabling simultaneous detection of all known ABCR variants. The ABCR genotyping microarray (the ABCR400 chip) was constructed by the arrayed primer extension (APEX) technology. Each sequence change in ABCR was included on the chip by synthesis and application of sequence-specific oligonucleotides. We validated the chip by screening 136 confirmed STGD patients and 96 healthy controls, each of whom we had analyzed previously by single strand conformation polymorphism (SSCP) technology and/or heteroduplex analysis. The microarray was >98% effective in determining the existing genetic variation and was comparable to direct sequencing in that it yielded many sequence changes undetected by SSCP. In STGD patient cohorts, the efficiency of the array to detect disease-associated alleles was between 54% and 78%, depending on the ethnic composition and degree of clinical and molecular characterization of a cohort. In addition, chip analysis suggested a high carrier frequency (up to 1:10) of ABCR variants in the general population. The ABCR genotyping microarray is a robust, cost-effective, and comprehensive screening tool for variation in one gene in which mutations are responsible for a substantial fraction of retinal disease. The ABCR chip is a prototype for the next generation of screening and diagnostic tools in ophthalmic genetics, bridging clinical and scientific research
Characterization of a novel 21-kb deletion, CFTRdele2,3 (21kb), in the CFTR gene: a cystic fibrosis mutation of a Slavic origin common in Central and East Europe.
No full textWe report a large genomic deletion of the cystic fibrosis transmembrane conductance regulator (CFTR) gene, viz., a deletion that is frequently observed in Central and Eastern Europe. The mutation, termed CFTRdele2,3(21 kb), deletes 21,080 bp spanning introns 1-3 of the CFTR gene. Transcript analyses have revealed that this deletion results in the loss of exons 2 and 3 in epithelial CFTR mRNA, thereby producing a premature termination signal within exon 4. In order to develop a simple polymerase chain reaction assay for this allele, we defined the end-points of the deletion at the DNA sequence level. We next screened for this mutation in a representative set of European and European-derived populations. Some 197 CF patients, including seven homozygotes, bearing this mutation have been identified during the course of our study. Clinical evaluation of CFTRdele2,3(21 kb) homozygotes and a comparison of compound heterozygotes for ΔF508/CFTRdele2,3(21 kb) with pairwise-matched ΔF508 homozygotes indicate that this deletion represents a severe mutation associated with pancreatic insufficiency and early age at diagnosis. Current data show that the mutation is particularly common in Czech (6.4% of all CF chromosomes), Russian (5.2%), Belorussian (3.3%), Austrian (2.6%), German (1.5%), Polish (1.5%), Slovenian (1.5%), Ukrainian (1.2%), and Slovak patients (1.1%). It has also been found in Lithuania, Latvia, Macedonia and Greece and has sporadically been observed in Canada, USA, France, Spain, Turkey, and UK, but not in CF patients from Bulgaria, Croatia, Romania or Serbia. Haplotype analysis has identified the same extragenic CF-haplotype XV-2c/KM. 19 'A' and the same infrequent intragenic microsatellite haplotype 16-33-13 (IVS8CA-IVS17bTA-IVS17bCA) in all examined CFTRdele2,3(21 kb) chromosomes, suggesting a common origin for this deletion. We conclude that the 21-kb deletion is a frequent and severe CF mutation in populations of Eastern- and Western-Slavic descent
Characterization of a novel 21-kb deletion, CFTRdele2,3(21 kb), in the CFTR gene: A cystic fibrosis mutation of Slavic origin common in Central and East Europe
No full textWe report a large genomic deletion of the cystic fibrosis transmembrane conductance regulator (CFTR) gene, viz., a deletion that is frequently observed in Central and Eastern Europe. The mutation, termed CFTRdele2,3(21 kb), deletes 21,080 bp spanning introns 1-3 of the CFTR gene. Transcript analyses have revealed that this deletion results in the loss of exons 2 and 3 in epithelial CFTR mRNA, thereby producing a premature termination signal within exon 4. In order to develop a simple polymerase chain reaction assay for this allele, we defined the end-points of the deletion at the DNA sequence level. We next screened for this mutation in a representative set of European and European-derived populations. Some 197 CF patients, including seven homozygotes, bearing this mutation have been identified during the course of our study. Clinical evaluation of CFTRdele2,3(21 kb) homozygotes and a comparison of compound heterozygotes for ΔF508/CFTRdele2,3(21 kb) with pairwise-matched ΔF508 homozygotes indicate that this deletion represents a severe mutation associated with pancreatic insufficiency and early age at diagnosis. Current data show that the mutation is particularly common in Czech (6.4% of all CF chromosomes), Russian (5.2%), Belorussian (3.3%), Austrian (2.6%), German (1.5%), Polish (1.5%), Slovenian (1.5%), Ukrainian (1.2%), and Slovak patients (1.1%). It has also been found in Lithuania, Latvia, Macedonia and Greece and has sporadically been observed in Canada, USA, France, Spain, Turkey, and UK, but not in CF patients from Bulgaria, Croatia, Romania or Serbia. Haplotype analysis has identified the same extragenic CF-haplotype XV-2c/KM. 19 'A' and the same infrequent intragenic microsatellite haplotype 16-33-13 (IVS8CA-IVS17bTA-IVS17bCA) in all examined CFTRdele2,3(21 kb) chromosomes, suggesting a common origin for this deletion. We conclude that the 21-kb deletion is a frequent and severe CF mutation in populations of Eastern- and Western-Slavic descent.link_to_subscribed_fulltex
Genotyping microarray (gene chip) for the ABCR (ABCA4) gene.
No full textItem does not contain fulltextGenetic variation in the ABCR (ABCA4) gene has been associated with five distinct retinal phenotypes, including Stargardt disease/fundus flavimaculatus (STGD/FFM), cone-rod dystrophy (CRD), and age-related macular degeneration (AMD). Comparative genetic analyses of ABCR variation and diagnostics have been complicated by substantial allelic heterogeneity and by differences in screening methods. To overcome these limitations, we designed a genotyping microarray (gene chip) for ABCR that includes all approximately 400 disease-associated and other variants currently described, enabling simultaneous detection of all known ABCR variants. The ABCR genotyping microarray (the ABCR400 chip) was constructed by the arrayed primer extension (APEX) technology. Each sequence change in ABCR was included on the chip by synthesis and application of sequence-specific oligonucleotides. We validated the chip by screening 136 confirmed STGD patients and 96 healthy controls, each of whom we had analyzed previously by single strand conformation polymorphism (SSCP) technology and/or heteroduplex analysis. The microarray was >98% effective in determining the existing genetic variation and was comparable to direct sequencing in that it yielded many sequence changes undetected by SSCP. In STGD patient cohorts, the efficiency of the array to detect disease-associated alleles was between 54% and 78%, depending on the ethnic composition and degree of clinical and molecular characterization of a cohort. In addition, chip analysis suggested a high carrier frequency (up to 1:10) of ABCR variants in the general population. The ABCR genotyping microarray is a robust, cost-effective, and comprehensive screening tool for variation in one gene in which mutations are responsible for a substantial fraction of retinal disease. The ABCR chip is a prototype for the next generation of screening and diagnostic tools in ophthalmic genetics, bridging clinical and scientific research
Geographic distribution and regional origin of 272 Cystic Fibrosis mutations in European populations.
No full textThe geographic distribution of 272 cystic fibrosis (CF) mutations has been studied by assessing the origin of 27,177 CF chromosomes from 29 European countries and three countries from the North of Africa. The 5 most common mutations are ΔF308 (66.8%), G542X (2.6%), N1303K (1.6%), G551D (1.5%) and W1282X (1.0%). The ΔF508 mutation has the highest relative frequency in Denmark (87.2%) and the lowest in Algeria (26.3%). Mutation G542X is common in the Mediterranean countries, with a mean frequency of 6.1%. N1303K is found in most of the western and Mediterranean countries and has the highest frequency in Tunisia (17.2%). The wide distribution of these mutations suggests an ancient origin. G551D is common in north-west and central Europe, but is uncommon in other parts of Europe. W1282X has the highest frequency in Israel (36.2%), being also common in most Mediterranean countries and north Africa. Seventeen mutations have frequencies between 0.1 and 0.9%, 1717-lG→A (0.83%), R553X (0.75%), ..
Common ABCA4 mutations in South Africans: frequencies, pathogenicity and genotype-phenotype correlations
No full textStargardt disease (STGD), a juvenile-onset form of macular dystrophy resulting in a severe reduction of central vision, may be inherited in either an autosomal recessive or autosomal dominant manner. To date the only gene found to be involved with the autosomal recessive form is ABCA4. Mutations in this gene are associated not only with STGD, but with other autosomal recessive retinal diseases. Due to the numerous mutations detected in ABCA4 and their associated phenotypic heterogeneity, a genotype-phenotype model has been proposed based on the amount of ABCA4 protein activity. Research in the Division of Human Genetics at the University of Cape Town (UCT) has suggested possible ABCA4 founder mutations underlying STGD in the South African Caucasian Afrikaner population and has identified seven (C1490Y, R602W, IVS38-10T>C, L2027F, V256V, G863A, and R152X) common mutations. In a cohort of patients affected with an ABCA4-associated retinopathy (AAR) a total of 36% were identified as having various bi-allelic combinations of the seven mutations.In the current study, SNaPshot PCR, allele-specific PCR (AS-PCR) and denaturing high performance liquid chromatography (dHPLC) analysis were used to screen for the seven mutations in a patient cohort and a control cohort. A high detection rate of bi-allelic disease-causing mutations in total of 28/72 patients (i.e. 38.89% were fully characterised) confirmed the designed assay to be a viable screening tool, which could be employed in a diagnostic setting. The detection of 12 heterozygotes in the Caucasian control samples (n = 269; 169 of which were specifically Afrikaner) resulted in an estimated background frequency of 4.46 per 100 individuals. This could be used by counsellors to discuss carrier risks with patients and their family members. Bioinformatic tools (PolyPhen, SIFT, PMUT, PANTHER PSEC, ESEfinder, and the BDGP Splice Site Prediction programme) revealed the predicted pathogenicity of the seven mutations to be as follows (in order of decreasing pathogenicity): C1490Y, R602W, V256V, R152X, G863A, L2027F, and IVS38-10T>C. Statistical analysis (using the Kruskal-Wallis test and the Wilcoxon Rank Sum test) showed no significant12effect of mutation combination on phenotype (i.e. AOO/severity as a measure of clinical outcome).To improve the understanding of the genotype-phenotype correlation a larger cohort of South African STGD patients with the same common mutations in various combinations and the availability of sufficient clinical data, is required. Further investigations into the genotype-phenotype correlation, combined with the information on the pathogenicity of the mutations, could result in increased understanding regarding the impact of each mutation, thus enhancing the clinical utility of identifying ABCA4 mutations
