Poster #13 - Association Between Serotonin Taransporter Promoter Regulatory Region (5-HTTLPR) Polymorphism and Attachment Continuity

• In Event: 3-159 - Poster Session 12
  In Poster Session: PS 12 Section - Biological Processes: Neuroscience and Genetics

Integrative Statement

Background: Continuity of attachment security has been reported to be modulated by life events and varied among researches (Waters et al.,2000; Hmilton,2000; Groh et al.,2014). Serotonin transporter promoter regulatory region (5-HTTLPR) polymorphism was found to moderate the influence of stressful life events (Caspi et al., 2003), but this result was not confirmed by a meta-analysis (Risch et al., 2009). The aim of the study was to examine the effect of 5-HTTLPR polymorphism on the attachment continuity from infancy to adolescence.

Method: Twenty Japanese adolescents (11 women) aged between 20 and 21 years old who have been our participants since their birth and their biological mothers joined in the study. Infant participants joined in the strange situation procedure (SSP) at 12 months old. Attachment of adolescents and their mothers were assessed by the Japanese version of Relationships Questionnaire (RQ; Bartholomew & Horowitz, 1991; Kato,1998) which was a self-report attachment measure. Samples of saliva were collected from adolescent participants by Oragene (DNA genotek) and genotyped for 5-HTTLPR polymorphism and RS25531 SNP by the capillary sequencing method.
Ethical approval for the study was obtained from the first author’s institutional ethics committee. Written informed consents were obtained from all participants.

Results: Infant attachment behaviors (proximity-and contact-seeking behavior, contact-maintaining behavior, resistant behavior, and avoidant behavior) were coded by 7 points Likert scale and attachment patterns were classified into secure (80%) and insecure(20%; ambivalent 15%, avoidant 5%) by the best-trained coder in the US. Distribution of subcategories of adolescent RQ were secure (40%) and insecure(60%; preoccupied 20%, fearful 30%, dismissing 10%). Attachment continuity from infancy to adolescence were 35% in the secure and 65% in the insecure group, κ=.11., p=.494 (Table1).
5-HTTLPR was in Hardy-Weinberg equation (p<.05). RS25531 SNP G allele with 5-HTTLPR long allele (16-repeats, L) as well as short allele (14-repeats, S) was regarded to reduce 5-HTTLPR transcriptional efficacy and designated as LG. We combined genotype of S/S and S/LG into S/S. S/S, S/L, and L/L were 75%, 25%, and 0% respectively. Those four infant attachment behaviors in the SSP were factor analyzed by maximum-likelihood method and rotated by promax rotation and extracted two factors, secure and ambivalence. Using these two factors and maternal RQ security score, covariance structure analysis yielded that S/L showed a significant positive pass coefficient in the association between infant security and adolescent RQ security (p<.05, Figure 1).

Conclusions: Continuity of attachment security was low without considering polymorphism. Our L carriers of infant secure group continued to be secure at adolescence and maternal security as an environment did not associate with adolescent security. This result suggests that L carriers are insusceptible from their experiences and corresponds partly with previous studies (Caspi et al.,2003; van IJzendoorn et al.,2010; van IJzendoorn et al.,2012). Most of participants of attachment-DNA researches have been Caucasians who had L/L allele while Japanese had very few L/L (Nakamura et al.,2000). The study has a limitation of sample size but contributes to the attachment-DNA research.

Authors

• Akira Saito, Tsurumi Junior College
  Presenting Author

• Yoshiaki Nomura, Tsurumi University
  Non-Presenting Author

• Hiroshi Tada, Toho University School of Medicine
  Non-Presenting Author