Munk H L, Svendsen A J, Hjelmborg J v B, Sorensen G L, Kyvik K O, Junker P
Department of Rheumatology C, Odense University Hospital, Denmark; University of Southern Denmark, Denmark.
The Danish Twin Registry, Epidemiology, Institute of Public Health, Denmark; University of Southern Denmark, Denmark.
Osteoarthritis Cartilage. 2014 Aug;22(8):1142-7. doi: 10.1016/j.joca.2014.06.027. Epub 2014 Jul 4.
The aim of this investigation was to estimate the heritability of circulating collagen IIA N-terminal propeptide (PIIANP) by studying mono- and dizygotic healthy twin pairs at different age and both genders.
598 monozygotic (MZ) and dizygotic (DZ) twin individuals aged 18-59 years were recruited from the Danish Twin Registry. PIIANP was measured by competitive ELISA. The similarity of circulating PIIANP among MZ and DZ twins was assessed by intraclass correlations according to traits. The heritability was estimated by variance component analysis accounting for additive and dominant genetic factors as well as shared and non-shared environment but ignoring epistasis (genetic inter-locus interaction) and gene-environment interaction.
The intraclass correlation of PIIANP in MZ and DZ twins was 0.69 (0.60-0.76) and 0.46 (0.34-0.58) respectively indicating a significant genetic impact on PIIANP in serum. Additive genetic effects explained 45% (21-70%), shared environment 24% (7-53%) and non-shared environment 31% (24-39%) of the total variance. The heritability estimate did not differ across ages and between genders.
The study shows that approximately 45% of the collagen IIA synthesis as assessed by the collagen IIA N-terminal propeptide in serum is attributable to genetic effectors while individual and shared environment account for 24% and 31% respectively. The heritability does not differ between genders or according to age.
本研究旨在通过对不同年龄和性别的单卵和双卵健康双胞胎进行研究，评估循环中IIA型胶原蛋白N端前肽（PIIANP）的遗传度。
从丹麦双胞胎登记处招募了598名年龄在18至59岁之间的单卵（MZ）和双卵（DZ）双胞胎个体。采用竞争性酶联免疫吸附测定法检测PIIANP。根据性状，通过组内相关系数评估MZ和DZ双胞胎中循环PIIANP的相似性。通过方差成分分析估计遗传度，该分析考虑了加性和显性遗传因素以及共享和非共享环境，但忽略了上位性（基因座间遗传相互作用）和基因-环境相互作用。
MZ和DZ双胞胎中PIIANP的组内相关系数分别为0.69（0.60 - 0.76）和0.46（0.34 - 0.58），表明血清中PIIANP受到显著的遗传影响。加性遗传效应解释了总方差的45%（21% - 70%），共享环境解释了24%（7% - 53%），非共享环境解释了31%（24% - 39%）。遗传度估计在不同年龄和性别之间没有差异。
该研究表明，血清中通过IIA型胶原蛋白N端前肽评估的IIA型胶原蛋白合成约45%归因于遗传因素，而个体和共享环境分别占24%和31%。遗传度在性别或年龄之间没有差异。
