MacGregor A J, Snieder H, Rigby A S, Koskenvuo M, Kaprio J, Aho K, Silman A J
Twin Research and Genetic Epidemiology Unit, St. Thomas' Hospital, London, UK.
Arthritis Rheum. 2000 Jan;43(1):30-7. doi: 10.1002/1529-0131(200001)43:1<30::AID-ANR5>3.0.CO;2-B.
Twin concordance data for rheumatoid arthritis (RA) on their own provide only limited insight into the relative genetic and environmental contribution to the disease. We applied quantitative genetic methods to assess the heritability of RA and to examine for evidence of differences in the genetic contribution according to sex, age, and clinical disease characteristics.
Data were analyzed from 2 previously published nationwide studies of twins with RA conducted in Finland and the United Kingdom. Heritability was assessed by variance components analysis. Differences in the genetic contribution by sex, age, age at disease onset, and clinical characteristics were examined by stratification. The power of the twin study design to detect these differences was examined through simulation.
The heritability of RA was 65% (95% confidence interval [95% CI] 50-77) in the Finnish data and 53% (95% CI 40-65) in the UK data. There was no significant difference in the strength of the genetic contribution according to sex, age, age at onset, or disease severity subgroup. Both study designs had power to detect a contribution of at least 40% from the common family environment, and a difference in the genetic contribution of at least 50% between subgroups.
Genetic factors have a substantial contribution to RA in the population, accounting for approximately 60% of the variation in liability to disease. Although tempered by power considerations, there is no evidence in these twin data that the overall genetic contribution to RA differs by sex, age, age at disease onset, and disease severity.
类风湿关节炎（RA）的双生子一致性数据本身仅能提供关于该疾病相对遗传和环境因素贡献的有限见解。我们应用数量遗传学方法来评估RA的遗传力，并检验是否存在根据性别、年龄和临床疾病特征的遗传贡献差异的证据。
分析了来自芬兰和英国先前发表的两项全国性RA双生子研究的数据。通过方差成分分析评估遗传力。通过分层检验性别、年龄、发病年龄和临床特征在遗传贡献上的差异。通过模拟检验双生子研究设计检测这些差异的效能。
在芬兰的数据中，RA的遗传力为65%（95%置信区间[95%CI]50 - 77），在英国的数据中为53%（95%CI 40 - 65）。根据性别、年龄、发病年龄或疾病严重程度亚组，遗传贡献强度没有显著差异。两种研究设计都有能力检测到来自共同家庭环境的至少40%的贡献，以及亚组间遗传贡献至少50%的差异。
遗传因素在人群中对RA有很大贡献，约占疾病易感性变异的60%。尽管受效能因素影响，但这些双生子数据中没有证据表明RA的总体遗传贡献因性别、年龄、发病年龄和疾病严重程度而有所不同。
