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- Study Description
Low and high birth weight are not only major causes of neonatal morbidity and mortality, but epidemiological data have established an association between birth weight and later life risk of adult metabolic diseases. Fetal growth is determined by complex interactions between fetal genes and the maternal uterine environment. Subtle or overt variation in maternal glucose tolerance, which is, in part, genetically determined, is related to fetal size at birth. Moreover, new emerging data suggest that genetic variation in the fetus can impact maternal metabolism (e.g., blood pressure and glucose tolerance). Given the above, we are addressing the hypothesis that, during pregnancy, gene-environment interactions in the context of the maternal-fetal unit impact fetal size at birth and maternal metabolism. Genes that control fetal growth or maternal metabolism during pregnancy are largely unknown, so the first step to address our hypothesis will be to identify genetic variation that impacts fetal growth and maternal metabolism and to determine the interaction of that variation with the intrauterine and fetal environment.
To accomplish this, we are performing genome wide association (GWA) mapping on a subset of ~37,000 DNA samples that were collected from mothers and their offspring as part of the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Study. HAPO is a multicenter, international study in which high quality phenotypic data related to fetal growth and maternal glucose metabolism has been collected from 25,000 pregnant women of varied racial and socio-demographic backgrounds using standardized protocols that were uniform across centers. For these studies, we are genotyping 1,500 infants and their mothers of European descent, 1,250 Afro-Caribbean infants and mothers, and 800 Hispanic (Mexican-American) infants and mothers. Genotyping is being performed using the Illumina Human610 Quad (European ancestry) and Human1M Duo (Afro-Caribbean and Hispanic subjects).
The specific aims for the project are as follows: (1) To apply analytic approaches for conducting GWA mapping studies on quantitative phenotypes related to offspring size at birth (birth weight, ponderal index, head circumference and adiposity) allowing for other known influences such as gestational age, parity, and maternal weight gain. (2) To apply the above approaches to identify genetic variation that impacts maternal glucose tolerance at ~28 weeks of gestation (fasting glucose, glucose during an oral glucose tolerance test, and insulin sensitivity expressed as quantitative traits) allowing for other known influences such as maternal weight gain, parity and age. (3) To examine the interaction between maternal genes, the intrauterine environment, and fetal genes to identify interactions that modulate genetic regulation of size at birth and fetal genetic variation that impacts on maternal glucose tolerance. GWA mapping will provide initial evidence for association of specific SNPs with the quantitative traits outlined above.
As low and high birth weight are not only major causes of neonatal morbidity and mortality but have also been associated with increased risk of metabolic diseases in adults, identification of genes that regulate fetal growth and maternal metabolism will provide novel information about the pathways that regulate these processes as well as important insight into susceptibility genes for chronic diseases like type 2 diabetes.
The Version 1 (v1) dbGaP release will include data only from the Hispanic study participants. The Version 2 (v2) dbGaP release will include data from the Hispanic and European ancestry study participants. The Version 3 (v3) dbGaP release will include data from the Afro-Caribbean, Hispanic and European ancestry subjects.
This study is part of the Gene Environment Association Studies initiative (GENEVA, http://www.genevastudy.org) funded by the trans-NIH Genes, Environment, and Health Initiative (GEI). The overarching goal is to identify novel genetic factors that contribute to maternal metabolism and birthweight through large-scale genome-wide association studies of infants and their mothers at multiple international sites. Genotyping was performed at the Broad Institute of MIT and Harvard, a GENEVA genotyping center. Data cleaning and harmonization was performed at the GEI-funded GENEVA Coordinating Center at the University of Washington.
- Study Types: Prospective, Observational, Cohort
Number of study subjects that have individual level data available through Authorized Access: 1834
- Authorized Access
- Publicly Available Data (Public ftp)
Connect to the public download site. The site contains release notes and manifests. If available, the site also contains data dictionaries, variable summaries, documents, and truncated analyses.
In the course of routine data cleaning and data analyses, investigators may incidentally identify genetic abnormalities that might influence the clinical care of an individual. These statements and recommendations have been developed to help investigators when they are informed of any such incidental findings.
- Study Inclusion/Exclusion Criteria
A pregnant woman was ineligible to participate in HAPO if any of the following exclusion criteria applied:
- Age < 18 years, i.e., has not completed 18th year of life by the first interview.
- Planning to deliver at another hospital or location.
- Date of last menstrual period is not certain AND no ultrasound estimation from 6-24 weeks of gestational age is available or will be available.
- Unable to complete OGTT within 32 weeks gestation, or currently > 31 weeks gestation.
- Known multiple pregnancy.
- Became pregnant with assistance of advanced reproductive technology such as in vitro fertilization (IVF) or superovulation with gonadotropins.
- Any unblinded blood glucose testing AND/OR diagnosis of GDM during this pregnancy prior to enrollment in this protocol.
- Previous diagnosis of diabetes requiring treatment with medication outside of pregnancy.
- Currently receiving treatment with oral glucocorticoids, thiazide diuretics, -blockers, ACE inhibitors, oral -mimetics, dilantin, or antiretroviral agents.
- Participation in another study which may interfere with the HAPO Study.
- Known to be HIV positive or to have Hepatitis B or C.
- Participation in the HAPO Study during a previous pregnancy.
- Inability to converse in language(s) used in field center forms without the aid of an interpreter.
Note: Women with any of the exclusion criteria present (except 11) were excluded since any of these criteria may confound study results. Women with criterion 11 present were excluded for protection of others since blood samples were transported across international borders.
- Molecular Data
Type Source Platform Number of Oligos/SNPs SNP Batch Id Comment Whole Genome Genotyping Illumina Human1M-Duov3_B 1185051 1049348 Whole Genome Genotyping Illumina Human610_Quadv1_B 601273 1048904
- Study History
2001-2006: Participant enrollment
2006: Final HAPO baby delivered
2006-2007: Data cleanup
06/2007: Initial results presented
HAPO enrolled over 25,000 pregnant women at 15 field centers in 9 countries. DNA was collected from ~18,000 mothers and 17,000 babies at 14 field centers. As part of this study, DNA from ~3,400 mothers and 3,400 babies (~90% of which were from a mother-baby pair) was included in this GWA study. Study subjects are of Hispanic (Bellflower, CA); Afro-Caribbean (Barbados); and European ancestry (Toronto, Canada, Belfast, UK, Brisbane and Newcastle, Australia) descent.
- Selected publications
- Diseases/Traits Related to Study (MESH terms)
- Study Attribution