Samples from the Greek island of Crete, MANOLIS cohort
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ABSTRACT:
PROVIDER: EGAS00001000067 | EGA |
REPOSITORIES: EGA
Similar Datasets
Project description:Whole-genome sequencing at 1x of samples from the Cretan Greek isolate collection HELIC-MANOLIS. Genome-wide association studies of complex traits have been successful in identifying common variant associations, but a substantial heritability gap remains. The field of complex trait genetics is shifting towards the study of low frequency and rare variants, which are hypothesised to have larger effects. The study of these variants can be empowered by focusing on isolated populations, in which rare variants may have increased in frequency and linkage disequilibrium tends to be extended. This work focuses on an isolated population from Crete, Greece. Sequencing is very efficient in isolated populations, because variants found in a few samples will be shared by others in extended haplotype contexts, supporting accurate imputation.
| EGAS00001000392 | EGA
Project description:Whole-genome sequencing at 1x of samples from the Cretan Greek isolate collection HELIC-MANOLIS. Genome-wide association studies of complex traits have been successful in identifying common variant associations, but a substantial heritability gap remains. The field of complex trait genetics is shifting towards the study of low frequency and rare variants, which are hypothesised to have larger effects. The study of these variants can be empowered by focusing on isolated populations, in which rare variants may have increased in frequency and linkage disequilibrium tends to be extended. This work focuses on an isolated population from Crete, Greece. Sequencing is very efficient in isolated populations, because variants found in a few samples will be shared by others in extended haplotype contexts, supporting accurate imputation.
| EGAD00001001637 | EGA
Project description:Isolated populations can empower the identification of rare variation associated with complex traits through next generation association studies. Here we have genotyped individuals from a Greek population isolate on the Illumina HumanExome Beadchip. The HELIC (Hellenic Isolated Cohorts) MANOLIS (Minoan Isolates) collection focuses on Anogia and surrounding Mylopotamos villages. Recruitment of this population-based sample was primarily carried out at the village medical centres. All individuals were older than 17 years and had to have at least one parent from the Mylopotamos area. www.helic.org **The data may not be used for population genetics analyses.**
| EGAS00001000630 | EGA
Project description:Isolated populations can empower the identification of rare variation associated with complex traits through next generation association studies. Here we have genotyped individuals from a Greek population isolate on the Illumina Human OmniExpress BeadChip array. The HELIC (Hellenic Isolated Cohorts) MANOLIS (Minoan Isolates) collection focuses on Anogia and surrounding Mylopotamos villages. Recruitment of this population-based sample was primarily carried out at the village medical centres. All individuals were older than 17 years and had to have at least one parent from the Mylopotamos area. www.helic.org **The data may not be used for population genetics analyses**
| EGAS00001000687 | EGA
Project description:If copy number variants (CNVs) are predominantly deleterious, we would expect them to be more efficiently purged from populations with a large effective population size (Ne) than from populations with a small Ne. Malaria parasites (Plasmodium falciparum) provide an excellent organism to examine this prediction, because this protozoan shows a broad spectrum of population structures within a single species, with large, stable, outbred populations in Africa, small unstable inbred populations in South America and with intermediate population characteristics in South East Asia. We characterized 122 single-clone parasites, without prior laboratory culture, from malaria-infected patients in 7 countries in Africa, SE Asia and S. America using a high density SNP/CNV microarray. We scored 134 high-confidence CNVs across the parasite exome, including 33 deletions and 102 amplifications, which ranged in size from <500bp to 59kb, as well as 10,107 flanking, biallelic SNPs. Overall, CNVs were rare, small and skewed towards low frequency variants, consistent with the deleterious model. Relative to African and SE Asian populations, CNVs were significantly more common in S. America, showed significantly less skew in allele frequencies, and were significantly larger. On this background of low frequency CNV, we also identified several high-frequency CNVs under putative positive selection using an FST outlier analysis. These included known adaptive CNVs containing rh2b and pfmdr1, and several other CNVs (e.g. DNA helicase, and 3 conserved proteins) that require further investigation. Our data are consistent with a significant impact of genetic structure on CNV burden in an important human pathogen. SNP/CGH hybridisation of 175 malaria parasite samples
2015-11-19 | E-GEOD-75137 | biostudies-arrayexpress
Project description:Transplant-associated thrombotic microangiopathy (TA-TMA) is a life-threatening complication of allogeneic hematopoietic cell transplantation (HCT). We hypothesized that pre-transplant genetic susceptibility is evident in adult TA-TMA patients at the level of TMA-associated variants and further investigated the association of genetic variants with clinical outcomes. We studied 30 patients with TA-TMA at a median of 73 (9-540) post-transplant days, donors of 18/30 patients and 30 control non-TMA HCT recipients, without significant differences in transplant characteristics. Genomic DNA from pre-transplant peripheral blood was analyzed by targeted next generation sequencing for complement regulatory genes and ADAMTS13. Donors presented significantly lower frequency of rare variants (p=0.049) and variants in exonic/splicing/UTR regions (p=0.025), compared to TA-TMA patients. Controls also showed a significantly lower frequency of rare variants in ADAMTS13 (p=0.001), CD46 (p=0.002), CFH (p=0.010) and CFI (p=0.031). Pathogenic variants were found in ADAMTS13, CFH, CFI and CFB, while homozygous pathogenic variants in ADAMTS13 and CFB were evident in only 4 TA-TMA patients (p=0.038). Patients refractory to conventional treatment (70%) were significantly (p=0.045) enriched for variants in exonic/splicing/UTR regions compared to responders. Nineteen of 30 patients (63%) succumbed to transplant-related mortality, which was also associated with significantly (p=0.012) increased frequency of variants in exonic/splicing/UTR regions. In conclusion, increased incidence of pathogenic, rare and variants in exonic/splicing/UTR regions of TA-TMA patients suggests genetic susceptibility not evident in controls or donors. Notably, variants in exonic/splicing/UTR regions were associated with poor response and survival. Therefore, pre-transplant genomic screening may be useful to intensify monitoring and early intervention in high-risk patients.
2019-04-18 | E-MTAB-7848 | biostudies-arrayexpress
Project description:Germline RUNX1 mutations are found in familial platelet disorders with predisposition to acute myelogenous leukemia (FPD/AML). This very rare disease is characterized by thrombocytopenia, platelet dysfunction and a 35% lifetime risk of developing MDS/AML and in rare cases also T-ALL. Here, we focus on a case of a man with a familial history of RUNX1 R174Q mutation who developed at the age of 42 years an EGIL T2-ALL and, two years after remission, an AML-M0. To investigate whether initial and relapsed leukemic blasts originated from the same clone, we performed CGH array and WES on both blasts populations. In both T2-ALL and AML-M0 samples, CGH array revealed loss of 1p36.32-23 and 17q11.2 and nine other small deletions. Both AML-M0 and T2-ALL blasts demonstrated clonal rearrangements of both TCRγ (Vγ9-Jγ1-1) and TCRδ (Dδ2-Jδ1 and Dδ2-Jδ3). 18 genes were found by WES to be mutated in both blasts at a frequency of more than 40%. Additional variants were identified only in T2-ALL or in AML-M0 evoking the existence of a common original clone, which gave rise to subclonal populations. MiSeq technology performed on peripheral blood-derived CD34+ cells five years prior T2-ALL development revealed only missense TET2 P1962T mutation at a frequency of 1% (which reaches a frequency of 50 % in fully transformed leukemic clone) suggesting that this mutation in association with germline RUNX1 R174Q mutation led to amplification of a hematopoietic clone susceptible to acquire other transforming alterations. Identification of clonal hematopoiesis with acquired mutations at low frequency in hematopoietic progenitors before leukemia development could clearly serve as a marker of pre-leukemic state and be helpful in patient care.
2017-06-29 | E-MTAB-4623 | biostudies-arrayexpress
Project description:Systemic lupus erythematosus (SLE) is the prototypic systemic autoimmune disease. It is thought that many common variant gene loci of weak effect act additively to predispose to common autoimmune diseases, while the contribution of rare variants remains unclear. Here we describe that rare coding variants in lupus-risk genes are present in most SLE patients and healthy controls. We demonstrate the functional consequences of rare and low frequency missense variants in the interacting proteins BLK and BANK, which are present alone, or in combination, in a substantial proportion of lupus patients. The rare variant found in patients, but not those found exclusively in controls, impair suppression of IRF and type-I IFN in human B cell lines and increase pathogenic lymphocytes in lupus-prone mice. Thus, rare gene variants are common in SLE and likely contribute to genetic risk.
2019-05-01 | GSE126307 | GEO
Project description:If copy number variants (CNVs) are predominantly deleterious, we would expect them to be more efficiently purged from populations with a large effective population size (Ne) than from populations with a small Ne. Malaria parasites (Plasmodium falciparum) provide an excellent organism to examine this prediction, because this protozoan shows a broad spectrum of population structures within a single species, with large, stable, outbred populations in Africa, small unstable inbred populations in South America and with intermediate population characteristics in South East Asia. We characterized 122 single-clone parasites, without prior laboratory culture, from malaria-infected patients in 7 countries in Africa, SE Asia and S. America using a high density SNP/CNV microarray. We scored 134 high-confidence CNVs across the parasite exome, including 33 deletions and 102 amplifications, which ranged in size from <500bp to 59kb, as well as 10,107 flanking, biallelic SNPs. Overall, CNVs were rare, small and skewed towards low frequency variants, consistent with the deleterious model. Relative to African and SE Asian populations, CNVs were significantly more common in S. America, showed significantly less skew in allele frequencies, and were significantly larger. On this background of low frequency CNV, we also identified several high-frequency CNVs under putative positive selection using an FST outlier analysis. These included known adaptive CNVs containing rh2b and pfmdr1, and several other CNVs (e.g. DNA helicase, and 3 conserved proteins) that require further investigation. Our data are consistent with a significant impact of genetic structure on CNV burden in an important human pathogen.
2015-11-19 | GSE75137 | GEO