Protein Information

ID 3304
Name IA 2
Synonyms IA 2; IA 2/PTP; IA2; ICA 512; ICA 3; ICA3; ICA512; Islet cell antigen 512…

Compound Information

ID 1689
Name IAA
CAS

Reference

PubMed Abstract RScore(About this table)
11134089 Gylling M, Tuomi T, Bjorses P, Kontiainen S, Partanen J, Christie MR, Knip M, Perheentupa J, Miettinen A: ss-cell autoantibodies, human leukocyte antigen II alleles, and type 1 diabetes in autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy. J Clin Endocrinol Metab. 2000 Dec;85(12):4434-40.
Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is caused by lack of functional products of the autoimmune regulator gene located on chromosome 21q22.3. The patients are at high risk of developing insulin-dependent (type 1) diabetes, but the positive predictive value of GAD65 or islet cell antibodies for type 1 diabetes is only 27%. Autoantibodies against the IA-2 tyrosine phosphatase-like protein (IA-2 ab) or insulin (IAA) have been suggested to be better markers for active ss-cell destruction. We studied these antibodies in sera from 60 Finnish patients with APECED, 12 of whom subsequently developed type 1 diabetes. Four (36%) of the 11 patients for whom we had prediabetic samples had IA-2 ab, and 4 (36%) had IAA. None of the 48 nondiabetics had IAA, and only 2 (4%) had IA-2 ab. Both had the antibodies for years without diabetes. Thus, IA-2 ab or IAA have a low sensitivity (36%), but high specificity (96% or 100%), with a positive predictive value of 67% for type 1 diabetes in patients with APECED. Data for human leukocyte antigen haplotypes were available for 59 of the patients, including 11 diabetics, and for 8 additional nondiabetic Finnish patients. No association between type 1 diabetes and high risk genotypes was seen. None of the 11 patients with type 1 diabetes, but 15 of the 56 (27%; P: < 0.05) nondiabetic patients and 24 of 93 (26%; P: < 0.05) of the control subjects had the DQB1*0602 allele, which is considered protective for type 1 diabetes. This is remarkable, as previously no positive or negative associations have been reported for any disease components of APECED with human leukocyte II antigens.
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