title: Two distinct MICA gene markers discriminate major autoimmune diabetes types.
abstract: The polymorphism of the major histocompatibility complex class I chain-related A gene is associated with type 1 diabetes mellitus. The major histocompatibility complex class I chain-related A gene 5 allele is significantly more frequent in Caucasian type 1 diabetes mellitus children than in healthy subjects, but no information is available on the association with adult-onset type 1 diabetes mellitus or with the so-called slowly progressive latent autoimmune diabetes of the adult in the same ethnic group. In this study we estimated the frequency of major histocompatibility complex class I chain- related A gene alleles and human leukocyte antigen-DRB1*03-DQA1*0501-DQB1*0201 and human leukocyte antigen-DRB1*04- DQA1*0301-DQB1*0302 in 195 type 1 diabetes mellitus subjects, in 80 latent autoimmune diabetes of the adult subjects, and in 158 healthy subjects from central Italy. Major histocompatibility complex class I chain-related A gene 5 was significantly associated with type 1 diabetes mellitus only in the 1-25 yr age group at diagnosis, and the odds ratio of the simultaneous presence of both major histocompatibility complex class I chain-related A gene 5 and human leukocyte antigen-DRB1*03- DQA1*0501-DQB1*0201 and/or human leukocyte antigen-DRB1*04-DQA1*0301-DQB1*0302 was as high as 54 and higher than 388 when compared with double negative individuals. Adult-onset type 1 diabetes mellitus (age at diagnosis, >25 yr) and latent autoimmune diabetes of the adult were significantly associated with major histocompatibility complex class I chain-related A gene 5.1, which was not significantly increased among diabetic children. Only the combination of major histocompatibility complex class I chain-related A gene 5.1 and human leukocyte antigen-DRB1*03-DQA1*0501-DQB1*0201 and/or human leukocyte antigen-DRB1*04-DQA1*0301-DQB1*0302 conferred increased risk for adult-onset type 1 diabetes mellitus or for latent autoimmune diabetes of the adult. Our study provides demonstration of the existence of distinct genetic markers for childhood/young-onset type 1 diabetes mellitus and for adult-onset type 1 diabetes mellitus/latent autoimmune diabetes of the adult, namely major histocompatibility complex class I chain-related A gene 5 and major histocompatibility complex class I chain-related A gene 5.1, respectively.
authors.affiliation: Department of Internal Medicine, University of Perugia, 06126 Perugia, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Gambelunghe
authors.forename: M
authors.initials: M
authors.lastname: Ghaderi
authors.forename: C
authors.initials: C
authors.lastname: Tortoioli
authors.forename: A
authors.initials: A
authors.lastname: Falorni
authors.forename: F
authors.initials: F
authors.lastname: Santeusanio
authors.forename: P
authors.initials: P
authors.lastname: Brunetti
authors.forename: C B
authors.initials: CB
authors.lastname: Sanjeevi
authors.forename: A
authors.initials: A
authors.lastname: Falorni
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000368:Aged; D003922:Diabetes Mellitus, Type 1 / Q000453:epidemiology / Q000235:genetics* / Q000276:immunology*; D005260:Female; D005819:Genetic Markers; D005838:Genotype; D006683:HLA-DQ Antigens / Q000235:genetics*; D006684:HLA-DR Antigens / Q000235:genetics*; D006239:Haplotypes; D015395:Histocompatibility Antigens Class I / Q000235:genetics*; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000235:genetics; D008875:Middle Aged; D012042:Registries; D012307:Risk Factors; D013548:Sweden / Q000453:epidemiology
chemical_list: D005819:Genetic Markers; D006683:HLA-DQ Antigens; D006684:HLA-DR Antigens; D015395:Histocompatibility Antigens Class I; C099187:MHC class I-related chain A; D008565:Membrane Proteins