IDDM12 (CTLA4) on 2q33 and IDDM13 on 2q34 in Genetic Susceptibility to Type 1 Diabetes (Insulin-dependent)

• Published in: Autoimmunity (Chur, Switzerland) Switzerland), 1999-01, Vol.31 (1), p.35-42
• Main Authors: Larsen, Zenia M., Kristiansen, Ole P., Mato, Eugenia, Johannesen, Jesper, Puig-Domingo, Manuel, de Leiva, Alberto, Nerup, Jørn, Pociot, Flemming
• Format: Article
• Language: English
• Subjects: Abatacept; Alleles; Antigens, CD; Antigens, Differentiation - genetics; Biological and medical sciences; chromosome 2; Chromosome Mapping; Chromosomes, Human, Pair 2 - genetics; CTLA-4; CTLA-4 Antigen; Diabetes Mellitus, Type 1 - genetics; Diabetes. Impaired glucose tolerance; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Etiopathogenesis. Screening. Investigations. Target tissue resistance; European Continental Ancestry Group - genetics; Genetic Predisposition to Disease - genetics; histocompatibility locus HLA; HLA; HLA Antigens - genetics; Humans; IDDM multiplex families; IDDM12 gene; IDDM13 gene; Immunoconjugates; Linkage Disequilibrium; Medical sciences; Microsatellite Repeats; TDT
• ISSN: 0891-6934; 1607-842X
• DOI: 10.3109/08916939908993857

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 D2SJ37-D2S164-D2S1471 markers (/rvalues 0.007, 0.02, and 0.007, respectively) using transmission disequilibrium testing (TDT) and the 7sp 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.