Dataset Information

The Environmental Determinants of Diabetes in the Young Study (TEDDY) Project

ABSTRACT:

The Environmental Determinants of Diabetes in the Young (TEDDY) Study investigates genetic and genetic-environmental interactions, including gestational events, childhood infections, dietary exposures, and other environmental factors after birth, in relation to the development of islet autoimmunity and type 1 diabetes (T1D). A consortium of six clinical centers assembled to participate in the development and implementation of the study to identify environmental triggers for the development of islet autoimmunity and T1D in genetically susceptible individuals. Beginning in 2004, the TEDDY study screened over 400,000 newborns for high-risk HLA-DR, DQ genotypes from both the general population and families already affected by T1D. The TEDDY study enrolled around 8,676 participants across six clinical centers worldwide (Finland, Germany, Sweden and three in the United States) in the 15-year prospective follow-up.

Participants are followed every three months for islet autoantibody (IA) measurements with blood sampling until four years of age and then at least every six months until the age of 15. After the age of four, autoantibody positive participants continue to be followed at three month intervals and autoantibody negative participants are followed at six-month intervals. In addition to the analysis of autoantibodies, additional data and sample collection are performed at each visit. Parents collect monthly stool samples in early childhood. The parents also fill out questionnaires at regular intervals in connection with study visits and record information about diet and health status in the child's TEDDY Book between visits. Continued long-term follow-up of the currently active TEDDY participants will provide important scientific information on early childhood diet, reported and measured infections, vaccinations, and psychosocial stressors that may contribute to the development of type 1 diabetes and islet autoimmunity.

Additional information on the TEDDY study is available in the following articles: The Environmental Determinants of Diabetes in the Young (TEDDY) Study. TEDDY Study Group. Annals of the New York Academy of Science, 2008 and TEDDY - The Environmental Determinants of Diabetes in the Young - An Observational Clinical Trial. Annals of the New York Academy of Science, 2006 Annals of the New York Academy of Science, 2008 and TEDDY - The Environmental Determinants of Diabetes in the Young - An Observational Clinical Trial. Annals of the New York Academy of Science, 2006

Details of the TEDDY protocol can be found in The Environmental Determinants of Diabetes in the Young (TEDDY): Genetic Criteria and International Diabetes Risk Screening of 421,000 infants. Pediatric Diabetes, 2011

There are three substudies associated with the current TEDDY project release in dbGaP:

TEDDY SNP Array - phs001037 with targeted SNP array data.
TEDDY Microbiome - phs001443 with metagenomic and 16S rRNA sequencing data.
TEDDY Gene Expression - phs001562 with gene expression data.

PROVIDER: phs001442 | dbGaP |

SECONDARY ACCESSION(S): PRJNA416160PRJNA416159

REPOSITORIES: dbGaP

ACCESS DATA

Dataset's files

Source:

			Action	DRS
	GapExchange_phs001442.v1.p1.xml	Xml
	dbGaPEx2.1.5.xsd	Other
	Study_Report.phs001442.TEDDY_ParentStudy.v1.p1.MULTI.pdf	Pdf
	manifest_phs001442.TEDDY_ParentStudy.v1.p1.c1.DS-T1DR-IRB-RD.pdf	Pdf
	datadict_v2.xsl	Other

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Project description:Both genetic and environmental factors are implicated in Type 1 Diabetes (T1D). Since environmental factors can trigger epigenetic changes, we hypothesized that variations in histone posttranslational modifications (PTMs) at the promoter/enhancer regions of T1D susceptible genes may be associated with T1D. We therefore evaluated histone PTM variations at known T1D susceptible genes in blood cells from T1D patients versus healthy non-diabetic controls, and explored their connections to T1D. We used the chromatin-immunoprecipitation-linked-to-microarray approach to profile key histone PTMs, including H3-lysine-4 trimethylation (H3K4me3), H3K27me3, H3K9me3, H3K9 acetylation (H3K9Ac) and H4K16Ac at genes within the T1D susceptible loci in lymphocytes, and H3K4me3, H3K9me2, H3K9Ac and H4K16Ac at the IDDM1 region in monocytes of T1D patients and healthy controls separately. We screened for potential variations in histone PTMs using computational methods to compare datasets from T1D and controls. Interestingly, we observed marked variations in H3K9Ac levels at the upstream regions of HLA-DRB1 and HLA-DQB1 within the IDDM1 locus in T1D monocytes relative to controls. Additional experiments with THP-1 monocytes demonstrated increased expression of HLA-DRB1 and HLA-DQB1 in response to interferon- and TNF-treatment that were accompanied by changes in H3K9Ac at the same promoter regions as that seen in the patient monocytes. These results suggest that the H3K9Ac status of HLA-DRB1 and HLA-DQB1, two genes highly associated with T1D, may be relevant to their regulation and transcriptional response towards external stimuli. Thus, the promoter/enhancer architecture and chromatin status of key susceptible loci could be important determinants in their functional association to T1D susceptibility. We evaluated histone PTM variations at known T1D susceptible genes in blood cells from T1D patients versus healthy non-diabetic controls, and explored their connections to T1D. We used the ChIP-chip approach to profile key histone PTMs, including histone H3K4me3, H3K27me3, H3K9me3, H3K9 acetylation (H3K9Ac) and H4K16Ac, at genes within the T1D susceptible loci in lymphocytes.

Dataset Information

The Environmental Determinants of Diabetes in the Young Study (TEDDY) Project

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