Abstract
In a first molecular genetic study Lakatos and colleagues found an association between attachment disorganization and the dopamine D4 receptor (DRD4) gene polymorphism, in particular in the presence of the -521 T allele in the promoter region of the DRD4 gene. Replication of their study in a sample of 132 infants did not confirm the role of the DRD4 7+ -allele and the -521C/T promoter gene in disorganized attachment. Although our sample was larger, and contained more children with CT or TT alleles, which enhanced the probability of finding the DRD4 and C/T interaction, the association was not found. Even when we combined our sample with the Lakatos sample, the interaction effect of the DRD4 and -521 C/T polymorphisms on disorganized attachment was absent.
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