Type 1 diabetes: Evidence of interaction between ACP1 and ADA1 gene polymorphisms

Background: ACP(1) (acid phosphatase locus 1, a cytosolic low-molecular-weight phosphotyrosin phosphatase) and ADA(1) (adenosine deaminase locus 1) are two polymorphic systems involved in immune reactions. Observed interactions at the biochemical and clinical levels between the two systems prompted this investigation of a possible interaction concerning susceptibility to type 1 diabetes. Material/Method: Two hundred eighty-seven children admitted consecutively to the hospital for type 1 diabetes and 727 healthy newborn infants were studied. All were from the Caucasian Italian population living in the central area of Italy. ACP(1) and ADA(1) genotypes were determined by DNA analysis. Results: In the type 1 diabetics the distribution of ACP(1) genotypes was dependent on the ADA(1) genotypes, showing all excess of the low-activity *A/*A and *A/*B genotypes in the ADA(1)*2 carriers compared with the ADA(1)*1/*1 subjects (OR: 2.200, 95%CI: 1.133-4.298). Such an association was not present in the healthy newborn infants. Conclusions: This investigation based on the biological effects of ACP(1) and ADA(1) on the immune system and on the known biochemical interaction between the two systems showed a significant interaction between the two system concerning susceptibility to type 1 diabetes. The low-activity ACP(1) genotypes *A/*A and *A/*B carrying the low-activity ADA(1)*2 allele were more common in type 1 diabetic than in healthy newborns (OR: 1.699 95%CI: 1.066-2.702).