The association between parenting and attachment security is moderated by a polymorphism in the mineralocorticoid receptor gene: Evidence for differential susceptibility

Maternal sensitive responsiveness and extreme insensitivity only partly explain the variance in attachment security. Differences in attachment security may well be rooted in the interplay of genetic variations and environmental factors. The association between parenting (observed sensitive responsiveness and extreme insensitivity) and attachment security (assessed with the Strange Situation Procedure) was hypothesized to be moderated by genes involved in the regulation of the stress response: the glucocorticoid receptor (GR) and mineralocorticoid receptor (MR) genes. A significant G × E interaction was found: infants carrying the minor MR allele (G) were significantly more securely attached if their mothers showed more sensitive responsiveness and significantly less securely attached if their mothers showed more extremely insensitive behaviors. These associations were not significant for carriers of the AA genotype of MR. Findings are discussed from a differential susceptibility perspective.

• The infant–mother attachment relationship is functional for the regulation of stress.
• The mineralocorticoid receptor (MR) gene is associated with stress regulation.
• Parenting partly explains differences in attachment.
• Children with the MR G allele were found to be more open to the effects of parenting.
• MR moderates infants’ susceptibility to positive and negative parenting (differential susceptibility).