PTPN22 and primary adrenal insufficiency: Conversely, in a meta-analysis published by Roycroft et al. in 2009, which examined C1858T polymorphism of PTPN22 gene in the population of Caucasian patients with Addison’s disease living in Britain and in Poland [29], sixty-one out of 502 (12.2%) British patients were the carriers of T allele in PTPN22 C1858T(R620W)SNP.