Cytotoxic T lymphocyte antigen 4 heterozygous codon 49 A/G dimorphism is associated to latent autoimmune diabetes in adults (LADA).
Autoimmune diabetes is an organ specific and multifactorial disorder with a classical onset as insulin dependent diabetes mellitus (IDDM) and with another form of onset as latent autoimmune diabetes in adults (LADA), which has a slower onset and a later progress to insulin dependency as a result of the beta cells destruction. The cytotoxic T lymphocyte-antigen 4 (CTLA4) has been identified as a susceptible marker of the disease; it is considered a down regulator of T cell function, playing a key role in autoimmunity. We analyzed CTLA4 codon 49 A/G polymorphism in 123 IDDM patients, 63 LADA patients and 168 healthy non-diabetic control individuals. The frequency of the heterozygous A/G genotype in LADA patients was significantly increased compared to IDDM patients (55.6 vs. 39.8%, p = 0.0415). There was no statistical significant difference in the distribution of the A/G dimorphism between autoimmune diabetes patients (LADA or IDDM) and non-diabetic control individuals. HLA DQ region is responsible for the genetic susceptibility to autoimmune diabetes in IDDM patients in about 50% and it has a lower effect in genetic susceptibility in LADA patients. Several other genetic loci are needed to develop autoimmune diabetes in adult patients. Therefore, LADA may be the result of a combined minor risk loci effect in a major risk haplotype.
Caputo
Mariela
M
Laboratory of Molecular Biology, Department of Genetic and Molecular Biology, School of Pharmacy and Biochemistry, University of Buenos Aires, Buenos Aires, Argentina.
Cerrone
Gloria Edith
GE
López
Ariel Pablo
AP
Villalba
Anabel
A
Krochik
Gabriela Andrea
GA
Cédola
Federico Norberto
FN
Targovnik
Héctor Manuel
HM
Frechtel
Gustavo Daniel
GD
D000328:Adult; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000235:genetics* / Q000276:immunology; D060908:CTLA-4 Antigen; D004247:DNA / Q000737:chemistry / Q000235:genetics; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics* / Q000276:immunology; D003924:Diabetes Mellitus, Type 2 / Q000235:genetics* / Q000276:immunology; D005838:Genotype; D006801:Humans; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D018807:Polymorphism, Single-Stranded Conformational
D015703:Antigens, CD; D000943:Antigens, Differentiation; D060908:CTLA-4 Antigen; C556706:CTLA4 protein, human; D004247:DNA