Ildikó Tóth

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

About 15% of one-year-old infants in non-clinical, low-risk and up to 80% in high-risk (eg maltreated) populations show extensive disorganized attachment behavior1, 2 in the Strange Situation Test.3 It has also been reported that disorganization of early attachment is a major risk factor for the development of childhood behavior problems.4 The collapse of organized attachment strategy has been explained primarily by inappropriate caregiving, but recently, the contribution of child factors such as neurological impairment5 and neonatal behavioral organization6 has also been suggested. Here we report an association between the DRD4 III exon 48-bp repeat polymorphism and attachment disorganization. Attachment behavior of 90 infants was tested in the Strange Situation and they were independently genotyped for the number of the 48-bp repeats by polymerase chain reaction (PCR). The 7-repeat allele was represented with a significantly higher frequency in infants classified as disorganized compared to non-disorganized infants: 12 of 17 (71%) vs 21 of 73 (29%) had at least one 7-repeat allele (χ2 = 8.66, df = 1, P < 0.005). The estimated relative risk for disorganized attachment among children carrying the 7-repeat allele was 4.15. We suggest that, in non-clinical, low-social-risk populations, having a 7-repeat allele predisposes infants to attachment disorganization.

Infant genotype may moderate sensitivity to maternal affective communications: attachment disorganization, quality of care, and the DRD4 polymorphism.

Abstract Disorganized attachment is an early predictor of the development of psychopathology in childhood and adolescence. Lyons-Ruth, Bronfman, and Parsons (1999) developed the AMBIANCE coding scheme to assess disrupted communication between mother and infant, and reported the link between maternal behavior and disorganized attachment. The Hungarian group found an association between a polymorphism of the DRD4 gene and disorganized attachment (Gervai et al., 2005; Lakatos et al., 2000, 2002). The present collaborative work investigated the interplay between genetic and caregiving contributions to disorganized attachment. Mother–infant dyads (138), from a Hungarian low-social-risk sample (96) and a US high-social-risk sample (42), were assessed for infant disorganized attachment behavior, for DRD4 gene polymorphisms, and for disrupted forms of maternal affective communication with the infant. In accord with literature reports, we found a robust main effect of maternal AMBIANCE scores on infant disorganization. However, this relation held only for the majority of infants who carried the short form of the DRD4 allele. Among carriers of the 7-repeat DRD4 allele, there was no relation between quality of maternal communication and infant disorganization. This interaction effect was independent of degree of social risk and maternal DRD4 genotype.

Transmission Disequilibrium Tests Confirm the Link Between DRD4 Gene Polymorphism and Infant Attachment

Following up the results of a previous population association study (Lakatos et al. [2000: Mol Psychiatry 5:633–637; Lakatos et al. [2002: Mol Psychiatry 7:27–31]) by analyses based on parental genetic data confirmed the link between infant attachment and the dopamine D4 receptor (DRD4) gene. Extended transmission disequilibrium tests (ETDT) were performed to determine whether biased transmission of exon III 48 basepair repeat alleles occurred to infants displaying disorganized and secure attachment behavior with their mothers. The overall allele‐wise TDTs were significant for both groups (P = 0.038 and 0.020, respectively): a trend for preferential transmission of the seven‐repeat allele to disorganized infants was observed (TDT  χ 2  = 3.27, df = 1, P = 0.071), and there was a significant non‐transmission of the same allele to securely attached infants (TDT  χ 2  = 6.00, df = 1, P = 0.014). Analysis of haplotypes of the exon III repeat and the −521 C/T promoter polymorphisms in family trios showed that the transmission bias in the larger secure group was due to the low‐rate transmission of the T.7 haplotype containing both the seven‐repeat and the −521 T alleles (TDT  χ 2  = 4.46, df = 1, P = 0.035). This suggests that not carrying the T.7 haplotype of the DRD4 gene may act as a resilience factor in the optimal development of early attachment.

Comparative Network Analysis of Preterm vs. Full-Term Infant-Mother Interactions

Several studies have reported that interactions of mothers with preterm infants show differential characteristics compared to that of mothers with full-term infants. Interaction of preterm dyads is often reported as less harmonious. However, observations and explanations concerning the underlying mechanisms are inconsistent. In this work 30 preterm and 42 full-term mother-infant dyads were observed at one year of age. Free play interactions were videotaped and coded using a micro-analytic coding system. The video records were coded at one second resolution and studied by a novel approach using network analysis tools. The advantage of our approach is that it reveals the patterns of behavioral transitions in the interactions. We found that the most frequent behavioral transitions are the same in the two groups. However, we have identified several high and lower frequency transitions which occur significantly more often in the preterm or full-term group. Our analysis also suggests that the variability of behavioral transitions is significantly higher in the preterm group. This higher variability is mostly resulted from the diversity of transitions involving non-harmonious behaviors. We have identified a maladaptive pattern in the maternal behavior in the preterm group, involving intrusiveness and disengagement. Application of the approach reported in this paper to longitudinal data could elucidate whether these maladaptive maternal behavioral changes place the infant at risk for later emotional, cognitive and behavioral disturbance.

Közös figyelem, atipikus anyai viselkedés és kötődés

Hatter es celok A kozos figyelem kepessegenek jellemzően 9 honapos kori megjeleneset kovetően a csecsemő triadikus (felnőtt—csecsemő—targy) interakciok soran oszthatja meg a targyakkal, esemenyekkel kapcsolatos elmenyeit egy masik szemellyel. E kepesseg fejlődesi utemeben megfigyelhető egyeni valtozatossagot a csecsemő adottsagai mellett a gondozoi kornyezet szocio-emocionalis jellemzői is befolyasolhatjak az interakciok minősegen keresztul. Modszer Kutatasunkban a csecsemők 9 honapos koraban, reszben kotott jatekhelyzetben figyeltuk meg anya—csecsemő parok triadikus helyzet letrehozasara iranyulo kezdemenyező viselkedeset, valamint kozos fi- gyelmi tevekenyseget. A viselkedesi jellemzőket az egyeves korban mert kotődes minősegevel es az anyai erzelmi kommunikacio atipikussaganak mertekevel vetettuk ossze. Eredmenyek Ahol tobb parhuzamos (egyszerű) kozos figyelem jellemezte az interakciot, ott az anya kevesebb időt toltott passziv monitorozassal, viszont tobbszor hivta fel a csecsemő figyelmet a targyra d...

Genetikai hatások a korai kötődés fejlődésében

Bowlby elmelete megjosolta, es a kovetkező evtizedek szamos empirikus vizsgalata bizonyitotta, hogy a korai kotődesi viselkedes kulonfele mintazatainak megjeleneset elsősorban a gondozoi viselkedes erzekenysegenek elteresei okozzak. Metaelemzesek szerint azonban ezek csak harmadat magyarazzak a kotődesi viselkedes varianciajanak. A gondozasi kornyezet mellett az 1990-es evekben felmerult a csecsemők egyeni jellemzőinek, pl. temperamentumanak befolyasa is a kotődes fejlődesere. A molekularis genetikai modszerek fejlődese a genetikai vizsgalatok erzekenysegenek novekedeset eredmenyezte, es 2000-ben kutatocsoportunk publikalt elsőkent a csecsemőkori kotődes egyeni valtozatossaganak hattereben allo specifikus genhatasokrol. Tanulmanyunkban attekintjuk, hogy a human genom projekt eredmenyeinek koszonhetően mikent bővult tudasunk az elmult 15 ev soran. Az attekintett kutatasok fő kerdesei, hogy a kornyezeti tenyezők mellett mely genek mely valtozatai gyakorolnak befolyast a csecsemők kotődesi viselkedesere, eze...