@article {433,
	title = {Genetic meta-analysis of twin birth weight shows high genetic correlation with singleton birth weight},
	journal = {Human Molecular Genetics},
	volume = {30},
	year = {2021},
	pages = {1894{\textendash}1905},
	abstract = {<p>Birth weight (BW) is an important predictor of newborn survival and health and has associations with many adult health outcomes, including cardiometabolic disorders, autoimmune diseases and mental health. On average, twins have a lower BW than singletons as a result of a different pattern of fetal growth and shorter gestational duration. Therefore, investigations into the genetics of BW often exclude data from twins, leading to a reduction in sample size and remaining ambiguities concerning the genetic contribution to BW in twins. In this study, we carried out a genome-wide association meta-analysis of BW in 42 212 twin individuals and found a positive correlation of beta values (Pearson\&$\#$39;s r = 0.66, 95\% confidence interval [CI]: 0.47-0.77) with 150 previously reported genome-wide significant variants for singleton BW. We identified strong positive genetic correlations between BW in twins and numerous anthropometric traits, most notably with BW in singletons (genetic correlation [rg] = 0.92, 95\% CI: 0.66-1.18). Genetic correlations of BW in twins with a series of health-related traits closely resembled those previously observed for BW in singletons. Polygenic scores constructed from a genome-wide association study on BW in the UK Biobank demonstrated strong predictive power in a target sample of Dutch twins and singletons. Together, our results indicate that a similar genetic architecture underlies BW in twins and singletons and that future genome-wide studies might benefit from including data from large twin registers.</p>
},
	doi = {10.1093/hmg/ddab121},
	author = {Beck, Jeffrey J and Pool, Ren{\'e} and van de Weijer, Margot and Chen, Xu and Krapohl, Eva and Gordon, Scott D and Nygaard, Marianne and Debrabant, Birgit and Palviainen, Teemu and van der Zee, Matthijs D and Baselmans, Bart and Finnicum, Casey T and Yi, Lu and Lundstr{\"o}m, Sebastian and van Beijsterveldt, Toos and Christiansen, Lene and Heikkil{\"a}, Kauko and Kittelsrud, Julie and Loukola, Anu and Ollikainen, Miina and Christensen, Kaare and Martin, Nicholas G and Plomin, Robert and Nivard, Michel and Bartels, Meike and Dolan, Conor and Willemsen, Gonneke and de Geus, Eco and Almqvist, Catarina and Magnusson, Patrik K E and Mbarek, Hamdi and Ehli, Erik A and Boomsma, Dorret I and Hottenga, Jouke-Jan}
}
@article {102,
	title = {Longitudinal heritability of childhood aggression.},
	journal = {Am J Med Genet B Neuropsychiatr Genet},
	year = {2016},
	month = {2016 Jan 19},
	abstract = {<p>The genetic and environmental contributions to the variation and longitudinal stability in childhood aggressive behavior were assessed in two large twin cohorts, the Netherlands Twin Register (NTR), and the Twins Early Development Study (TEDS; United Kingdom). In NTR, maternal ratings on aggression from the Child Behavior Checklist (CBCL) were available for 10,765 twin pairs at age 7, for 8,557 twin pairs at age 9/10, and for 7,176 twin pairs at age 12. In TEDS, parental ratings of conduct disorder from the Strength and Difficulty Questionnaire (SDQ) were available for 6,897 twin pairs at age 7, for 3,028 twin pairs at age 9 and for 5,716 twin pairs at age 12. In both studies, stability and heritability of aggressive behavioral problems was high. Heritability was on average somewhat, but significantly, lower in TEDS (around 60\%) than in NTR (between 50\% and 80\%) and sex differences were slightly larger in the NTR sample. In both studies, the influence of shared environment was similar: in boys shared environment explained around 20\% of the variation in aggression across all ages while in girls its influence was absent around age 7 and only came into play at later ages. Longitudinal genetic correlations were the main reason for stability of aggressive behavior. Individual differences in CBCL-Aggressive Behavior and SDQ-Conduct disorder throughout childhood are driven by a comparable but significantly different genetic architecture. \&copy; 2016 Wiley Periodicals, Inc.</p>
},
	issn = {1552-485X},
	doi = {10.1002/ajmg.b.32420},
	author = {Porsch, Robert M and Christel Middeldorp and Cherny, Stacey S and Eva Krapohl and Catharina E. M. van Beijsterveldt and Loukola, Anu and Korhonen, Tellervo and Pulkkinen, Lea and Corley, Robin and Rhee, Soo and Kaprio, Jaakko and Rose, Richard R and Hewitt, John K and Sham, Pak and Robert Plomin and Dorret I. Boomsma and Meike Bartels}
}
