Sulfonylurea receptor 1 gene variants are associated with gestational diabetes and type 2 diabetes but not with altered secretion of insulin.
OBJECTIVE
To investigate the possible association of the variants in the nucleotide binding fold regions of the sulfonylurea receptor 1 (SUR1) gene with gestational diabetes mellitus (GDM), type 2 diabetes, and altered insulin secretion in Finnish subjects.


METHODS
The nucleotide binding fold regions of the SUR1 gene were amplified with polymerase chain reaction and screened by the single-strand conformational polymorphism analysis in 42 subjects with GDM and 40 subjects with type 2 diabetes. Detected variants were further investigated in 377 normoglycemic subjects by restriction fragment-length polymorphism analysis. The effect of the variants of the SUR1 gene on first-phase insulin secretion was studied in 295 normoglycemic subjects.


RESULTS
In subjects with GDM or type 2 diabetes, one amino acid change (S1369A), four silent substitutions (R1273R, L829L, T759T, and K649K), and three intron variants were identified in the nucleotide binding fold regions of the SUR1 gene. A tagGCC allele of exon 16 splice acceptor site was more frequent in subjects with GDM (0.55 allele frequency, n = 42) and type 2 diabetes (0.60, n = 40) than in normoglycemic subjects (0.43, n = 377) (P1 = 0.024 and P2 = 0.009, respectively). Similarly, an AGG allele of the R1273R polymorphism was more common in subjects with GDM (0.87) and type 2 diabetes (0.87) than in normoglycemic subjects (0.74) (P1 = 0.009 and P2 = 0.001, respectively). However, the S1369A, R1273R, and cagGCC-->tagGCC variants of the SUR1 gene were not associated with altered first-phase insulin secretion in 295 normoglycemic subjects.


CONCLUSIONS
These results suggest that a functional variant that contributes to the risk of GDM and type 2 diabetes may locate close to the SUR1 gene.
Rissanen
J
J
Department of Medicine, University of Kuopio, Finland.
Markkanen
A
A
Kärkkäinen
P
P
Pihlajamäki
J
J
Kekäläinen
P
P
Mykkänen
L
L
Kuusisto
J
J
Karhapää
P
P
Niskanen
L
L
Laakso
M
M
D018528:ATP-Binding Cassette Transporters; D000328:Adult; D000368:Aged; D019943:Amino Acid Substitution; D003924:Diabetes Mellitus, Type 2 / Q000235:genetics*; D016640:Diabetes, Gestational / Q000235:genetics*; D005091:Exons; D005190:Family; D005260:Female; D014644:Genetic Variation; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000097:blood / Q000378:metabolism*; D000078790:Insulin Secretion; D007438:Introns; D008297:Male; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D018807:Polymorphism, Single-Stranded Conformational; D015221:Potassium Channels / Q000235:genetics*; D024661:Potassium Channels, Inwardly Rectifying; D011247:Pregnancy; D011955:Receptors, Drug / Q000235:genetics*; D064233:Sulfonylurea Receptors
C577507:ABCC8 protein, human; D018528:ATP-Binding Cassette Transporters; D007328:Insulin; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D011955:Receptors, Drug; D064233:Sulfonylurea Receptors