Dopamine D4 receptor (DRD4) gene polymorphism is associated with attachment disorganization in infants

Area of Science:

• Developmental Psychology
• Behavioral Genetics
• Neuroscience

Background:

• Disorganized attachment behavior affects a significant percentage of infants, increasing their risk for childhood behavioral problems.
• While caregiver behavior is a primary explanation for attachment disorganization, child-specific factors like neurological impairments are increasingly recognized.
• The DRD4 gene, involved in dopamine signaling, has been implicated in various behavioral traits.

Purpose of the Study:

• To investigate the association between the DRD4 III exon 48-bp repeat polymorphism and disorganized attachment behavior in infants.
• To determine if specific DRD4 gene variants predispose infants to attachment disorganization.

Main Methods:

• Attachment behavior was assessed in 90 infants using the Strange Situation Test.
• Infants were genotyped for the DRD4 III exon 48-bp repeat polymorphism using polymerase chain reaction (PCR).
• Statistical analyses, including chi-squared test and relative risk estimation, were performed.

Main Results:

• A significantly higher frequency of the 7-repeat allele of the DRD4 gene was found in infants exhibiting disorganized attachment (71%) compared to non-disorganized infants (29%).
• Infants carrying at least one 7-repeat allele had a 4.15 times higher estimated relative risk for disorganized attachment.
• The association remained significant even in a low-social-risk population.

Conclusions:

• The DRD4 III exon 48-bp repeat polymorphism, specifically the 7-repeat allele, is associated with disorganized attachment in infants.
• This genetic variant may predispose infants to developing disorganized attachment patterns, particularly in non-clinical settings.
• Findings highlight the interplay between genetic factors and early caregiving in shaping infant attachment.