title: IDDM12 (CTLA4) on 2q33 and IDDM13 on 2q34 in genetic susceptibility to type 1 diabetes (insulin-dependent).
abstract: Type 1 diabetes (insulin-dependent) is a multifactorial disease with polygenic susceptibility. The major genetic component (IDDM1) resides within the HLA region, but several non-HLA loci have been implicated in the genetic susceptibility. In the present study, we have analysed two such loci, IDDM12 (CTLA4) on 2q33 and IDDM13 on 2q34, in Danish (n = 254) and Spanish (n = 39) type 1 diabetic multiplex families. No significant evidence of linkage of IDDM12 was observed in any of the two studied data sets. However, when the present data were combined with previously published data, they strengthened the evidence of linkage at this locus, p = 0.00002. For the IDDM13 region, we found some positive evidence of linkage of the D2S137-D2S164-D2S1471 markers (p-values 0.007, 0.02, and 0.007, respectively) using transmission disequilibrium testing (TDT) and the Tsp version of the TDT. Importantly, random transmission of all tested alleles was observed in unaffected offspring (p > 0.3). Stratification for HLA (high risk and non-high risk genotypes) in the Danish families did not reveal heterogeneity at IDDM12 or IDDM13. In conclusion, our data on an entirely new family data set did not support the existence of IDDM12 as a type 1 diabetes susceptibility locus in the Danish population. In addition, we found support for evidence of linkage and association of the IDDM13/D2S137-D2S1471 region (approximately 3.5 cM) to type 1 diabetes, however, further studies are needed to substantiate this observation.
authors.affiliation: Steno Diabetes Center, Niels Steensensvej 2, Gentofte, Denmark.
authors.forename: Z M
authors.initials: ZM
authors.lastname: Larsen
authors.forename: O P
authors.initials: OP
authors.lastname: Kristiansen
authors.forename: E
authors.initials: E
authors.lastname: Mato
authors.forename: J
authors.initials: J
authors.lastname: Johannesen
authors.forename: M
authors.initials: M
authors.lastname: Puig-Domingo
authors.forename: A
authors.initials: A
authors.lastname: de Leiva
authors.forename: J
authors.initials: J
authors.lastname: Nerup
authors.forename: F
authors.initials: F
authors.lastname: Pociot
mesh_terms: D000069594:Abatacept; D000483:Alleles; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000235:genetics*; D060908:CTLA-4 Antigen; D002874:Chromosome Mapping; D002889:Chromosomes, Human, Pair 2 / Q000235:genetics*; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics*; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D006680:HLA Antigens / Q000235:genetics; D006801:Humans; D018796:Immunoconjugates; D015810:Linkage Disequilibrium; D018895:Microsatellite Repeats; D044465:White People / Q000235:genetics
chemical_list: D015703:Antigens, CD; D000943:Antigens, Differentiation; D060908:CTLA-4 Antigen; C556706:CTLA4 protein, human; D006680:HLA Antigens; D018796:Immunoconjugates; D000069594:Abatacept