Karason Ari, Love Thorvardur Jon, Gudbjornsson Bjorn
deCODE Genetics, Reykjavik, Iceland.
Rheumatology (Oxford). 2009 Nov;48(11):1424-8. doi: 10.1093/rheumatology/kep243. Epub 2009 Sep 9.
We have studied the prevalence of PsA in Reykjavik, Iceland, in a population-based cohort, and using the Icelandic genealogy database we have estimated the risk ratio (RR) spanning five generations.
The national identification numbers of all 220 living Icelanders in Reykjavik known to have PsA were linked with the genealogy database. RRs for developing PsA were estimated in first-degree relatives (FDRs) to fifth-degree relatives of PsA cases. The kinship coefficient (KC) for PsA was also calculated. The control populations were 1000 and 10,000 sets of matched Icelandic subjects for each proband, respectively.
FDRs to fourth-degree relatives of patients with PsA had RRs of 39, 12, 3.6 and 2.3, respectively (all P-values < 0.0001), reflecting a strong genetic component, whereas the fifth-degree relatives had an RR of 1.2 (P = 0.236). KCs of 5.0, 3.4, 1.7, 1.3, 1.0, 0.8 and 0.7 were observed for the first seven excluded meioses (all P-values < 0.0001), confirming the familial risk.
Patients with PsA in Reykjavik, Iceland, are significantly more related to each other than to randomly sampled control subjects. This is in agreement with previous reports, but the present study examines the inheritance in more distantly related individuals. These findings indicate that in addition to a strong and complex genetic component in PsA, there is an important environmental contribution.
我们在冰岛雷克雅未克的一个基于人群的队列中研究了银屑病关节炎（PsA）的患病率，并利用冰岛族谱数据库估计了五代人的风险比（RR）。
将雷克雅未克所有已知患有PsA的220名在世冰岛人的国家识别号与族谱数据库相关联。估计PsA患者的一级亲属（FDR）至五级亲属患PsA的RR。还计算了PsA的亲属系数（KC）。对照人群分别为每个先证者匹配的1000名和10000名冰岛受试者。
PsA患者的FDR至四级亲属的RR分别为39、12、3.6和2.3（所有P值<0.0001），反映出较强的遗传成分，而五级亲属的RR为1.2（P = 0.236）。在前七个排除的减数分裂中观察到的KC分别为5.0、3.4、1.7、1.3、1.0、0.8和0.7（所有P值<0.0001），证实了家族风险。
冰岛雷克雅未克的PsA患者之间的亲属关系明显高于随机抽样的对照受试者。这与先前的报告一致，但本研究考察了关系更远的个体的遗传情况。这些发现表明，除了PsA中存在强大而复杂的遗传成分外，环境因素也有重要贡献。
