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Study Description

The Family Investigation of Nephropathy and Diabetes (FIND) is a multicenter study designed to identify genetic determinants of diabetic kidney disease. Study subjects were recruited from eleven centers and in many ethnic groups throughout the United States. A genome-wide association study (GWAS) was conducted with the Affymetrix 6.0 chip.

Subjects (index cases) with diabetes and kidney disease were initially recruited, and their parents and siblings were invited to participate. Genetic material from these participants was used to genotype markers throughout the genome.

For association-based testing, a case-control design was implemented with study subjects selected primarily from the index cases of the families. Unrelated controls were selected from families where a case was not already selected. Several study sites also contributed non-FIND subjects, both cases and controls (consent forms for the release of FIND and non-FIND subjects/samples are included in this dbGaP release).

Cases were selected if they met study criteria for diabetic nephropathy or met inclusion criteria based on elevated serum creatinine levels and abnormal urine protein excretion. Similarly, controls were long-term diabetics with otherwise normal kidney function. See inclusion/exclusion criteria section for a detailed description for the FIND study as a whole and this GWAS.

The goal of the FIND study is to identify genes that influence susceptibility to diabetic kidney disease, leading to a better understanding of how kidney disease develops. In the long run, this may lead to improved treatment and prevention of diabetic kidney disease.

  • Study Type: Case-Control
  • dbGaP estimated ancestry components using GRAF-pop
  • Number of study subjects that have individual level data available through Authorized Access: 2622

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.

Study Inclusion/Exclusion Criteria

Cases for the GWAS were selected from FIND probands or siblings (see Knowler, et al., PMID: 15642484). The remaining cases, both FIND and non-FIND, were eligible if they had diabetic nephropathy or met one or more of the following criteria:

  1. Albumin-to-Creatinine ratio (ACR) ≥ 0.3
  2. Protein-Creatinine ratio (PCR) ≥ 0.5
  3. Glomerular Filtration Rate (MDRD formula) ≤ 60
  4. Serum Creatinine ≥ 1.6 mg/dL for Males, or ≥ 1.4 mg/dL for Females

For the GWAS, the above criteria are considered to be the strict case inclusion criteria. Additional subjects were included in the GWAS, if they were azotemic and had normal proteinuria, based upon the following loose case criteria:

  1. ACR ≤ 0.03
  2. GFR ≤ 60
  3. Serum Creatinine ≥ 1.6 mg/dL for Males, or ≥ 1.4 mg/dL for Females

Controls were selected from the remaining unrelated FIND family members, FIND controls, and contributed non-FIND subjects. All controls were long term (≥10 years) diabetics with healthy kidney function based on one or more of the following criteria:

  1. ACR ≤ 0.03
  2. PCR ≤ 0.05
  3. GFR ≥ 60
  4. Serum Creatinine ≤ 1.6 mg/dL for Males, or ≤ 1.4mg/dL for Females

Subjects meeting the above criteria are considered controls based on strict control inclusion criteria. Several subjects were allowed inclusion in the GWAS even if one or more of the above values was out of range. If a subject met at least three of the above criteria (or at least one of the above criteria in certain instances), the investigators reviewed the subject for further inclusion in the GWAS. If, based upon a full record review, the investigators determined the subject eligible for inclusion, the subject was allowed inclusion based upon loose criteria. Furthermore, all controls subjects, strict and loose, have had diabetes for at least 10 years.

DNA samples for eligible cases and controls were sent to Affymetrix for sample processing and genotype contrast QC. Bird seed call-rate QC was performed by TGEN. Genotypes with call rates below 95% were re-genotyped and removed from further analysis if problems persisted.

FIND statisticians then applied further QC measures which included sex verification, calculating the proportion of heterozygous genotypes, duplicate sample concordance, and pairwise identity-by-descent (IBD) estimation. Samples with minor errors are listed in the "FIND_QC_ActionsForResolution" files included with this dataset.

Molecular Data
TypeSourcePlatformNumber of Oligos/SNPsSNP Batch IdComment
Whole Genome Genotyping Affymetrix AFFY_6.0 934940 52074
Study History

Please refer to the following URL:

Selected publications
Diseases/Traits Related to Study (MESH terms)
Authorized Data Access Requests
Study Attribution