The association of variable number of tandem repeats of the insulin gene with susceptibility to type 1 diabetes among Korean subjects.
BACKGROUND
There is ethnic variation in the variable number of tandem repeats of the insulin gene (INS VNTR), one of the susceptibility loci for developing type 1 diabetes (T1D). We evaluated the influence of the genotypes and subdivisions of INS VNTR on the development of T1D in Korean subjects.


METHODS
The study included 352 Korean patients, under the age of 18 years who were diagnosed as having T1D, and 356 control subjects. The insulin - 23HphI A/T single nucleotide polymorphism was used as a marker of class I and III alleles. Surrounding polymorphisms at nucleotide positions + 1127, + 1140, + 2331 and + 2336 were determined as subdivisions of INS VNTR.


RESULTS
Classes I/I, I/III and III/III were observed at frequencies of 95.8, 4.2 and 0% among all subjects, respectively. Class I/III genotype was significantly less frequent in patients with T1D than in controls (2.56 versus 5.90%; odds ratio 0.419; P = 0.039). In a subdivision analysis, the ID/ID genotype was decreased among patients (P = 0.017, adjusted P = 0.085) and the IC allele tended to increase. The frequency of the class I/III genotype was significantly lower among patients who were diagnosed when younger than 7 years of age than in controls (odds ratio 0.115; P = 0.011).


CONCLUSIONS
INS VNTR has predominance of class I over class III alleles and is associated with susceptibility to T1D in Koreans. In addition, INS VNTR shows distinctive susceptibility according to the age at the onset of T1D.
Chung
Hye Rim
HR
Department of Pediatrics, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.
Yang
Sei Won
SW
Shin
Choong Ho
CH
Park
Kyong Soo
KS
Lee
Young Ah
YA
Kim
Jae Hyun
JH
Lee
Sun Hee
SH
Kim
Ji Hyun
JH
D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D044466:Asian People / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D003922:Diabetes Mellitus, Type 1 / Q000208:ethnology / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D007223:Infant; D007328:Insulin / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D018598:Minisatellite Repeats; D020641:Polymorphism, Single Nucleotide; D056910:Republic of Korea
D007328:Insulin