Association between haptoglobin gene variants and diabetic nephropathy: haptoglobin polymorphism in nephropathy susceptibility.
OBJECTIVE
The Hp(1)/Hp(2) DNA polymorphism has previously been implicated in susceptibility to diabetic nephropathy in some but not all studies. In an attempt to clarify these conflicting findings, we conducted a case-control association study in a Caucasian population.


METHODS
We recruited 224 and 285 type 1 diabetic patients with (cases) and without (controls) nephropathy, respectively, from 2 centres based in Northern Ireland and the Republic of Ireland. Hp(1)/Hp(2) genotyping was performed using a combination of long-range and multiplex PCR. Allele and genotype frequencies in cases and controls were compared using the chi(2) test.


RESULTS
There was a statistically significant increase in the frequency of the Hp(2) allele in cases compared to controls (65.6 vs. 58.6%, OR = 1.35, 95% CI: 1.04-1.76, p = 0.03). The distributions of genotypes were in Hardy-Weinberg equilibrium for both cases and controls, and the overall frequency of the Hp(1) allele was 38.3%, which is similar to that found in other Western European populations.


CONCLUSIONS
The results suggest that the Hp(2) allele may confer susceptibility to nephropathy in patients with type 1 diabetes.
Conway
Bryan R
BR
Nephrology Research Group, Queen's University Belfast, Belfast, UK. BryanConway@ntlworld.com
Savage
David A
DA
Brady
Hugh R
HR
Maxwell
Alexander P
AP
D000293:Adolescent; D015897:Comorbidity; D004252:DNA Mutational Analysis; D003922:Diabetes Mellitus, Type 1 / Q000453:epidemiology* / Q000235:genetics*; D003928:Diabetic Nephropathies / Q000453:epidemiology* / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease / Q000453:epidemiology / Q000235:genetics; D014644:Genetic Variation / Q000235:genetics; D006242:Haptoglobins / Q000235:genetics*; D006801:Humans; D007494:Ireland / Q000453:epidemiology; D008297:Male; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D015995:Prevalence; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors
C485359:HP protein, human; D006242:Haptoglobins