Complement gene variants in relation to autoantibodies to beta cell specific antigens and type 1 diabetes in the TEDDY Study
SCIENTIFIC REPORTS
Authors: Torn, Carina; Liu, Xiang; Hagopian, William; Lernmark, Ake; Simell, Olli; Rewers, Marian; Ziegler, Anette-G; Schatz, Desmond; Akolkar, Beena; Onengut-Gumuscu, Suna; Chen, Wei-Min; Toppari, Jorma; Mykkanen, Juha; Ilonen, Jorma; Rich, Stephen S.; She, Jin-Xiong; Sharma, Ashok; Steck, Andrea; Krischer, Jeffrey
Abstract
A total of 15 SNPs within complement genes and present on the ImmunoChip were analyzed in The Environmental Determinants of Diabetes in the Young (TEDDY) study. A total of 5474 subjects were followed from three months of age until islet autoimmunity (IA: n = 413) and the subsequent onset of type 1 diabetes (n = 115) for a median of 73 months (IQR 54-91). Three SNPs within ITGAM were nominally associated (p < 0.05) with IA: rs1143678 [Hazard ratio; HR 0.80; 95% CI 0.66-0.98; p = 0.032], rs1143683 [HR 0.80; 95% CI 0.65-0.98; p = 0.030] and rs4597342 [HR 1.16; 95% CI 1.01-1.32; p = 0.041]. When type 1 diabetes was the outcome, in DR3/4 subjects, there was nominal significance for two SNPs: rs17615 in CD21 [HR 1.52; 95% CI 1.05-2.20; p = 0.025] and rs4844573 in C4BPA [HR 0.63; 95% CI 0.43-0.92; p = 0.017]. Among DR4/4 subjects, rs2230199 in C3 was significantly associated [HR 3.20; 95% CI 1.75-5.85; p = 0.0002, uncorrected] a significance that withstood Bonferroni correction since it was less than 0.000833 (0.05/60) in the HLA-specific analyses. SNPs within the complement genes may contribute to IA, the first step to type 1 diabetes, with at least one SNP in C3 significantly associated with clinically diagnosed type 1 diabetes.
Absence of linkage between type III protein S deficiency and the PROS1 and C4BP genes in families carrying the protein S Heerlen allele
BLOOD
Authors: EspinosaParrilla, Y; Morell, M; Souto, JC; Borrell, M; HeineSuner, D; Tirado, I; Volpini, V; Estivill, X; Sala, N
Abstract
To elucidate the molecular basis of hereditary protein S (PS) deficiency and, in particular, type III or free PS deficiency, the allelic distribution and segregation patterns of the PS gene (PROS1) polymorphisms P626A/G and S460P (PS Heerlen) have been analyzed in a group of 45 proposita suffering from type I or type III PS deficiency. No differences between patients and controls were found in the frequency of the P626A/G alleles. By contrast, the frequency of the PS Heerlen allele in the group of patients with type III PS deficiency (9 of 46 chromosomes, P = .196) was significantly higher (P < .001) than in the control group (1 of 300 chromosomes, P = .003). The A allele of P626A/G was always associated with the P allele of S460P. However, this haplotype did not cosegregate with the type III PS-deficient phenotype in 3 of the families. Furthermore, multipoint linkage analysis excluded the whole PROS1 gene in 1 of these families, which is in agreement with the absence of mutations in the PROS? gene, as determined by sequence analysis. Finally, linkage analysis with 4 microsatellite markers linked to the C4BPB and C4BPA loci also excluded these two genes, From these results we conclude that, at least in some families, the molecular basis of type III PS deficiency is not due to the Mendelian inheritance of a single defect in the PROS1 or in the C4BP genes. (C) 1997 by The American Society of Hematology.