Background: Type 1 Diabetes Mellitus (T1DM) is a multifactorial autoimmune disease. The
Protein Tyrosine Phosphatase Non-receptor 22 (PTPN22) gene is an important negative regulator of
signal transduction through the T‐cell Receptors (TCR). A PTPN22 polymorphism, C1858T, has been
found to be a risk determinant for several autoimmune diseases, including T1DM, in different populations.
Objective: The present study was aimed to analyze a possible association between the C1858T polymorphism
in Egyptian children with T1DM.
Methods: This case-control study included 240 children divided evenly between T1DM patients and
controls. The PTPN22 C1858T polymorphism was genotyped using polymerase chain reaction with
Restriction Fragment Length Polymorphism (RFLP).
Results: Both the 1858CΤ and 1858ΤΤ genotypes and the 1858T allele were found more frequently in
patients (32.5% and 18.7%, respectively) than in controls (10% and 5.0%, respectively), P=0.013 and
P=0.007, respectively. Among females, the 1858T allele was more common in patients (18%) than in
controls (2.6%), P=0.014.
Conclusion: These findings suggest that the PTPN22 1858T allele could be a T1DM susceptibility factor
in the Egyptian population and that it might play a different role in susceptibility to T1DM according
to gender in T1DM patients.