Psoriatic arthritis is characterized as seronegative arthritisthat aVects patients suVering from psoriasis [1]. Aetiologyof this condition is still not clear and therapeuticapproaches are not always successful. However, goodresponse to bromocriptine therapy decreasing prolactin lev-els in patients with psoriatic arthritis has been demonstratedin some reports [ 2, 3]. Prolactin acts as a cytokine and playsa role in pathogenesis of systemic autoimmune diseasessuch as rheumatoid arthritis and systemic lupus erythemat-osus [4, 5]. Moreover, high serum prolactin levels wereobserved in group of patients with psoriasis and linkbetween keratinocytes hyperproliferation and prolactin hasbeen proposed [6]. The peptide hormone prolactin is pro-duced from pituitary lactotrophs and extrapituitary tissuessuch as lymphocytes as well. Extrapituitary PRL produc-tion is regulated by an alternative promoter located 5.8 kbupstream from the pituitary one [7, 8]. A functional singlenucleotide polymorphism (SNP) G/T at the position i1149of this extrapituitary promoter has been observed and inlymphocytes higher PRL mRNA expression found to beconnected with G allele [9]. In our work we studiedi1149G/T SNP PRL in group of 83 Czech patients withpsoriatic arthritis (PsA).We genotyped i1149G/T SNP in 83 PsA patients and123 healthy individuals (control group). PsA patients: 43(51.8%) females, 40 (48.2%) males, average age 54.1 years.Control group: 40 (32.5%) females and 83 (67.5%) males,average age 38.7 years. This study was approved by theEthical Committee of the Third Faculty of Medicine,Charles University, Prague.PCR-RFLP methodology was used for i1149G/T SNPdetection. PCR: The 137 bp region of the PRL extrapitu-itary promoter was ampli Wed by employing following prim-ers: Forward primer 5 GCAGGTCAAGATAACCTGGAand reverse primer 5 CATCTCAGAGTTGAATTTATTTCCTT. The PCR reaction was run under these conditions:initial temperature 94°C for 2 min, then 32 cycles with94°C for 17 s, 55°C for 17 s, 72°C for 17 s, and Wnal tem-perature 72°C for 1 min. RFLP: ApoI restriction endonu-clease was used. The three genotypes were identiWed asindicated: the homozygote TT was characterized by120 + 17 bp, the homozygote GG by 85 + 35 + 17 bp, andthe heterozygote GT genotype by 120 + 85 + 35 + 17 bpDNA fragments. Results were evaluated by Chi square testwith Bonferroni correction.The genotypes and alleles frequency of i1149G/T SNPPRL extrapituitary promoter were similar in group of PsApatients and control group (Table1). We did not Wnd anydiVerences in genotype and allele distribution betweenhealthy female and male and between female and malepatients with psoriatic arthritis, respectively (data notshown). Moreover, we correlated genotype and allele distri-bution of i1149G/T SNP with clinical feature of psoriaticarthritis, such as age of onset psoriasis and radiologicaltype of psoriatic arthritis. In Table2 there are results of thiscorrelation, where no signiWcant association was detected.In conclusion, i1149G/T SNP of the extrapituitary pro-lactin promoter is not associated with psoriatic arthritis (seeTable 1) and its characteristic such as the onset of skinlesion and radiological type of arthritis (see Table2). OurWndings could indicate that i1149G/T SNP prolactin