Although the environmental influences on infant attachment disorganization and security are well-studied, little is known about their heritability. Candidate gene studies have shown small, often non-replicable effects. In this study, we gathered the largest sample (N = 657) of ethnically homogenous, 14-month-old children with both observed attachment and genome-wide data. First, we used a Genome-Wide Association Study (GWAS) approach to identify single nucleotide polymorphisms (SNPs) associated with attachment disorganization and security. Second, we annotated them into genes (Versatile Gene-based Association Study) and functional pathways. Our analyses provide evidence of novel genes (HDAC1, ZNF675, BSCD1) and pathways (synaptic transmission, cation transport) associated with attachment disorganization. Similar analyses identified a novel gene (BECN1) but no distinct pathways associated with attachment security. The results of this first extensive, exploratory study on the molecular-genetic basis of infant attachment await replication in large, independent samples.

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Attachment and Human Development
Generation R Study Group

Pappa, I., Székely, E., Mileva-Seitz, V., Luijk, M., Bakermans-Kranenburg, M., van IJzendoorn, R., & Tiemeier, H. (2015). Beyond the usual suspects: a multidimensional genetic exploration of infant attachment disorganization and security. Attachment and Human Development, 17(3), 288–301. doi:10.1080/14616734.2015.1037316