A candidate type 2 diabetes polymorphism near the HHEX locus affects acute glucose-stimulated insulin release in European populations: results from the EUGENE2 study.
OBJECTIVE
In recent genome-wide association studies, two single nucleotide polymorphisms (SNPs) near the HHEX locus were shown to be more frequent in type 2 diabetic patients than in control subjects. Based on HHEX's function during embryonic development of the ventral pancreas in mice, we investigated whether these SNPs affect beta-cell function in humans.


METHODS
A total of 854 nondiabetic subjects, collected from five European clinical centers, were genotyped for the HHEX SNPs rs1111875 and rs7923837 and thoroughly characterized by an oral glucose tolerance test (OGTT). To assess glucose-stimulated insulin release, a subgroup of 758 subjects underwent an intravenous glucose tolerance test (IVGTT).


RESULTS
SNPs rs1111875 and rs7923837 were not associated with anthropometric data (age, weight, height, BMI, body fat, and waist and hip circumference). After adjustment for center, family relationship, sex, age, and BMI, both SNPs were also not associated with glucose and insulin concentrations in the fasting state and during the OGTT or with measures of insulin sensitivity. Furthermore, HHEX SNP rs1111875 was not associated with insulin release during the IVGTT. By contrast, the minor A-allele of HHEX SNP rs7923837 was significantly associated with higher IVGTT-derived first-phase insulin release before and after appropriate adjustment (P = 0.013 and P = 0.014, respectively).


CONCLUSIONS
A common genetic variation in the 3'-flanking region of the HHEX locus, i.e., SNP rs7923837, is associated with altered glucose-stimulated insulin release. This SNP's major allele represents a risk allele for beta-cell dysfunction and, thus, might confer increased susceptibility of beta-cells toward adverse environmental factors.
Internal Medicine IV, Medical Clinic Tübingen, Otfried-Müller-Str. 10, D-72076 Tübingen, Germany.
Harald
H
Staiger
Alena
A
Stancáková
Jone
J
Zilinskaite
Markku
M
Vänttinen
Torben
T
Hansen
Maria Adelaide
MA
Marini
Ann
A
Hammarstedt
Per-Anders
PA
Jansson
Giorgio
G
Sesti
Ulf
U
Smith
Oluf
O
Pedersen
Markku
M
Laakso
Norbert
N
Stefan
Andreas
A
Fritsche
Hans-Ulrich
HU
Häring
D000328:Adult; D015992:Body Mass Index; D003924:Diabetes Mellitus, Type 2 / Q000235:genetics*; D005060:Europe; D005260:Female; D005947:Glucose / Q000494:pharmacology*; D018149:Glucose Intolerance / Q000235:genetics*; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D012016:Reference Values; D014157:Transcription Factors / Q000235:genetics*; D049629:Waist-Hip Ratio; D044465:White People / Q000235:genetics
C078492:HHEX protein, human; D018398:Homeodomain Proteins; D007328:Insulin; D014157:Transcription Factors; D005947:Glucose