title: Contribution of known and unknown susceptibility genes to early-onset diabetes in scandinavia: evidence for heterogeneity.
abstract: In an attempt to identify novel susceptibility genes predisposing to early-onset diabetes (EOD), we performed a genome-wide scan using 433 markers in 222 individuals (119 with diabetes) from 29 Scandinavian families with > or =2 members with onset of diabetes < or =45 years. The highest nonparametric linkage (NPL) score, 2.7 (P < 0.01), was observed on chromosome 1p (D1S473/D1S438). Six other regions on chromosomes 3p, 7q, 11q, 18q, 20q, and 21q showed a nominal P value <0.05. Of the EOD subjects in these 29 families, 20% were GAD antibody positive and 68% displayed type 1 diabetes HLA risk alleles (DQB*02 or 0302). Mutations in maturity-onset diabetes of the young (MODY) 1-5 genes and the A3243G mitochondrial DNA mutation were detected by single-strand conformation polymorphism and direct sequencing. To increase homogeneity, we analyzed a subsample of five families with autosomal dominant inheritance of EOD (greater than or equal to two members with age at diagnosis < or =35 years). The highest NPL scores were found on chromosome 1p (D1S438-D1S1665; NPL 3.0; P < 0.01) and 16q (D16S419; NPL 2.9; P < 0.01). After exclusion of three families with MODY1, MODY3, and mitochondrial mutations, the highest NPL scores were observed on chromosomes 1p (D1S438; NPL 2.6; P < 0.01), 3p (D3S1620; NPL 2.2; P < 0.03), 5q (D5S1465; NPL 2.1; P < 0.03), 7q (D7S820; NPL 2.0; P < 0.03), 18q (D18S535; NPL 1.9; P < 0.04), 20q (D20S195; NPL 2.5; P < 0.02), and 21q (D21S1446; NPL 2.2; P < 0.03). We conclude that considerable heterogeneity exists in Scandinavian subjects with EOD; 24% had MODY or maternally inherited diabetes and deafness, and approximately 60% were GAD antibody positive or had type 1 diabetes-associated HLA genotypes. Our data also point at putative chromosomal regions, which could harbor novel genes that contribute to EOD.
authors.affiliation: Department of Endocrinology, Wallenberg laboratory, Malmö University Hospital, Malmö, Sweden. cecilia.lindgren@endo.mas.lu.se
authors.forename: Cecilia M
authors.initials: CM
authors.lastname: Lindgren
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Widén
authors.forename: Tiinamaija
authors.initials: T
authors.lastname: Tuomi
authors.forename: Haiyan
authors.initials: H
authors.lastname: Li
authors.forename: Peter
authors.initials: P
authors.lastname: Almgren
authors.forename: Timo
authors.initials: T
authors.lastname: Kanninen
authors.forename: Olle
authors.initials: O
authors.lastname: Melander
authors.forename: Jianping
authors.initials: J
authors.lastname: Weng
authors.forename: Markku
authors.initials: M
authors.lastname: Lehto
authors.forename: Leif C
authors.initials: LC
authors.lastname: Groop
mesh_terms: D000328:Adult; D017668:Age of Onset; D000368:Aged; D001323:Autoantibodies / Q000097:blood; D015415:Biomarkers; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics* / Q000276:immunology; D005192:Family Health; D005260:Female; D018740:Genetic Heterogeneity; D005819:Genetic Markers; D020022:Genetic Predisposition to Disease; D005820:Genetic Testing; D015894:Genome, Human; D005838:Genotype; D006683:HLA-DQ Antigens / Q000235:genetics; D059866:HLA-DQ beta-Chains; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010375:Pedigree; D012537:Scandinavian and Nordic Countries
chemical_list: D001323:Autoantibodies; D015415:Biomarkers; D005819:Genetic Markers; D006683:HLA-DQ Antigens; D059866:HLA-DQ beta-Chains; C069051:HLA-DQB1 antigen