Twin-singleton differences in brain structure using structural equation modelling
Twin-singleton differences in brain structure using structural equation modelling
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DOI：
10.1093/brain/awf035
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发表时间：
2002-02-01
期刊：
影响因子：
14.5
通讯作者：
Boomsma, DI
中科院分区：
文献类型：
--
作者：
Pol, HEH;Posthuma, D;Boomsma, DI
双胞胎研究对于研究健康和疾病中人类大脑形态变化的遗传影响非常重要。然而，双胞胎方法因其所谓的非普遍性而受到批评，这是由于双胞胎与单胞胎相比在宫内和家庭环境方面的差异。为了测试双胞胎-单胞胎的差异是否使对脑体积变化的遗传贡献的解释复杂化，使用MRI扫描了112对双胞胎和34对他们的兄弟姐妹的大脑，平均（标准差）年龄为30.7（9.6）岁。采用最大似然模型拟合分析了出生顺序、卵性和孪生兄弟差异对脑容量测量的影响。在出生顺序、卵性和双胞胎-单胞胎状态之间，方差均质。不论卵性如何，第二胎双胞胎的颅内体积均小于第一胎双胞胎和兄弟姐妹。第二胎双胞胎的灰质体积小于第一胎双胞胎。双胞胎的白色物质比同胞小。校正颅内体积后，这些组之间的灰质和白色物质差异不再显着。双胞胎和单胞胎的全脑、侧脑室和第三脑室体积相当。总之，第二胎双胞胎的颅内体积小于第一胎双胞胎和兄弟姐妹。这表明第二胎双胞胎的早期大脑发育异常，这与双胞胎出生顺序相关的次优产前和围产期环境一致。由于其他脑容量的措施是可比的组之间，双胞胎研究可以提供可靠的估计遗传性的脑容量的措施，这些可以推广到单胎人口。
Twin studies are important to investigate genetic influences on variation in human brain morphology in health and disease. However, the twin method has been criticized for its alleged non-generalizability due to differences in the intrauterine and family environment of twins, compared with singletons. To test whether twin-singleton differences complicate interpretation of genetic contributions on variation in brain volume, brains from 112 pairs of twins and 34 of their siblings with a mean (standard deviation) age of 30.7 (9.6) years were scanned using MRI. The influence of birth order, zygosity and twin-sibling differences on brain volume measures was analysed using maximum-likelihood model fitting. Variances were homogeneous across birth order, zygosity and twin-singleton status. Irrespective of zygosity, intracranial volume was smaller in second-born twins compared with first-born twins and compared with siblings. Grey matter volume was smaller in second-born twins compared with first-born twins. White matter was smaller in twins compared with siblings. Differences in grey and white matter between these groups were no longer significant after correction for intracranial volume. Total brain, and lateral and third ventricle volumes were comparable in twins and singletons. In conclusion, second-born twins have a smaller intracranial volume than their first-born co-twins and siblings. This suggests aberrant early brain development in second-born twins, which is consistent with the suboptimal pre- and perinatal environment related to birth order in twins. Since other brain volume measures were comparable between the groups, twin studies can provide reliable estimates of heritabilities in brain volume measures and these can be generalized to the singleton population.