Impact of c242T Polymorphism of p22phox in Diabetic type1 Nephropathy

Study Overview
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Brief Summary
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The physiopathology of diabetic nephropathy (DN) is unclear. To investigate risk factor, the investigators choose to look about some oxidative stress genes. Today a one-gene explanation is not really possible. So the theory of some genetic predisposition to DN is more likely. The aim of the study is to look about the association of the C282T polymorphism of P22phox, a sub unit of the nicotinamide adenine dinucleotide phosphate-oxidase (NADPH oxidase) in the occurrence of DN. To follow the oxidative stress pathway of the DN, the investigators also investigate three other polymorphisms: -429 T/C, -374 T/A polymorphism of advanced glycation end-products receptor (AGER) and the p.Arg261Gln polymorphism of the 12 lipoxygenase (ALOX 12). Discordant data suggest a link between the first 2 polymorphisms and DN. The last polymorphism is correlated to albuminuria in diabetic patients.

Detailed Description
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To avoid confounding factors, we choose type 1 diabetic patients. We plan, with the data of literature a number need to be significative with a power of 80% and an Alpha risk at 5%, the inclusion of 160 patients for our primary analyze of p 22 phox. Those patients are included consequentially from the diabetic consultation of the university hospital of Grenoble, if they have a history of more than 20 years of diabetes. Those patients have been separated according to the existence of DN, and their polymorphism. Then we estimate with the Fisher test the prevalence of DN in risky patient, and the prevalence of the risky phenotype in the nephropathic patients. Then we investigate with the same statistical test the -429 T/C,he -374 T/A AGER and p.Arg261Gln 12 ALOX polymorphisms.

Official Title
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Impact of c242T Polymorphism of p22phox in the Development of Diabetic Nephropathy,in Caucasian Diabetic Type 1 Patient.

Conditions
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Type 1 Diabetes Mellitus, Diabetic Nephropathy

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: caucasian diabetic type 1 older than 18 years old written consent Exclusion Criteria: other etiology of diabetic nephropathy pregnancy other type of diabetes

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| diabetic nephropathy group<br>patient with diabetic nephropathy, defined as Albuminuria > 30 mg/day or urinary Albumine/ creatinine ratio > 3 mg/mmol ; or GFR estimated by MDRD less than 60 ml/min.1,73m². With no other etiology of diabetic nephropathy. | |
| diabetic retinopathy group<br>patient with diabetic retinopathy defined as showing at least one micro aneurysm on retinography. Without nephropathy defined as above | |
| no complication group<br>patient without diabetic nephropathy or retinopathy | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| comparison of prevalence of homozygous polymorphism between the DN-group and the non-DN group |  | on day 1 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| comparison of polymorphism of p22phox between the ND group and the sub-group of non-ND patients with diabetic retinopathy only |  | day 1 | 
| comparison of polymorphism prevalence between the 3 groups |  | day 1 | 
| delay between diabetes diagnosis and ND onset by genetic polymorphism | Kaplan Meier method | 20 years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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caucasian, diabetic nephropathy, CYBA, p22phox, RAGE, 12LOX, genetic, Type 1 Diabetes Mellitus with Diabetic Dermatitis, more than twenty years of diabetes duration, older than 18 years, no nephropathy other than diabetic nephropathy