Dopaminerge Polymorphismen und frühkindliche Regulationsprobleme

Interacting effects of maternal responsiveness, infant regulatory problems and dopamine D4 receptor gene in the development of dysregulation during childhood: A longitudinal analysis

Recent longitudinal studies have indicated that affective and behavioral dysregulation in childhood is associated with an increased risk for various negative outcomes in later life. However, few studies to date have examined early mechanisms preceding dysregulation during early childhood. Aim of this study was to elucidate early mechanisms relating to dysregulation in later life using data from an epidemiological cohort study on the long-term outcome of early risk factors from birth to adulthood. At age 3 months, mothers and infants were videotaped during a nursing and playing situation. Maternal responsiveness was evaluated by trained raters. Infant regulatory problems were assessed on the basis of a parent interview and direct observation by trained raters. At age 8 and 11 years, 290 children (139 males) were rated on the Child Behavior Checklist (CBCL). Additionally, participants were genotyped for the dopamine D4 receptor (DRD4) exon 3 VNTR polymorphism. A significant three-way interaction between maternal responsiveness, DRD4 genotype and infant regulatory problems was detected predicting the CBCL-dysregulation profile (CBCL-DP). Carriers of the DRD4 7r allele with regulatory problems at age 3 months showed significantly more behavior problems associated with the CBCL-DP during childhood when exposed to less maternal responsiveness. In contrast, no effect of maternal responsiveness was observed in DRD4 7r carriers without infant regulatory problems and in non-carriers of the DRD4 7r allele. This prospective longitudinal study extends earlier findings regarding the association of the CBCL-DP with early parenting and later psychopathology, introducing both DRD4 genotype and infant regulatory problems as important moderators.

Dopamine D4 receptor and serotonin transporter gene effects on the longitudinal development of infant temperament

Existing studies of the effect on infant temperament of the 48 base pair variable number of tandem repeats polymorphism in exon 3 of the dopamine D4 receptor gene, DRD4 VNTR, and the serotonin transporter-linked polymorphic region, 5-HTTLPR, have provided contradictory results, and age seems to be an important factor. The present study investigated the effect of these two polymorphisms on the stability of infant temperament between 4 and 9 months of age. Furthermore, the effect of a recently discovered single nucleotide polymorphism which modulates the 5-HTTLPR (rs25531) was investigated in relation to infant temperament. The study sample consisted of 90 infants, who were assessed by parental report at the two ages under consideration using the Revised Infant Behavior Questionnaire. It was found that infants carrying the 7-repeat allele of the DRD4 VNTR had higher levels of Negative Affect. Furthermore, there was an interaction between DRD4 VNTR and 5-HTTLPR genotype such that infants with the DRD4 VNTR 7-repeat allele and the highest expressing 5-HTTLPR genotype (L(A) L(A) ) had the highest level of Negative Affect. These effects were largely driven by scores on the Falling Reactivity scale. Genetic effects were stable across age. The results emphasize the need for developmental studies of genetic effects on temperament.

From regulatory problems in infancy to attention-deficit/hyperactivity disorder in childhood: a moderating role for the dopamine D4 receptor gene?

OBJECTIVE

To examine whether the dopamine receptor D4 gene (DRD4) exon III VNTR moderates the risk of infants with regulatory disorders for developing attention-deficit/hyperactivity disorder (ADHD) later in childhood.

STUDY DESIGN

In a prospective longitudinal study of children at risk for later psychopathology, 300 participants were assessed for regulatory problems in infancy, DRD4 genotype, and ADHD symptoms and diagnoses from childhood to adolescence. To examine a potential moderating effect on ADHD measures, linear and logistic regressions were computed. Models were fit for the main effects of the DRD4 genotype (presence or absence of the 7r allele) and regulatory problems (presence or absence), with the addition of the interaction term. All models were controlled for sex, family adversity, and obstetric risk status.

RESULTS

In children without the DRD4-7r allele, a history of regulatory problems in infancy was unrelated to later ADHD. But in children with regulatory problems in infancy, the additional presence of the DRD4-7r allele increased the risk for ADHD in childhood.

CONCLUSIONS

The DRD4 genotype seems to moderate the association between regulatory problems in infancy and later ADHD. A replication study is needed before further conclusions can be drawn, however.

A prospective study on the persistence of infant crying, sleeping and feeding problems and preschool behaviour

AIM

To determine the persistence of regulatory problems (RP), i.e. excessive crying (>3 months of age), feeding and sleeping difficulties from infancy to preschool age, and to evaluate whether RP at 5 months are predictive of preschool adaptive behaviour and social skills.

METHOD

A prospective population study of newborns admitted to neonatal care. RP at 5, 20 and 56 months of age were obtained via parent interviews and neurological examination and preschool adaptive behaviour and social skills by parent ratings. Logistic and linear regression analyses were conducted and controlled for psychosocial and neurological factors.

RESULTS

More than half of the sample had RP at least at one measurement point. In about 8% of infants, RP persisted across the preschool years. Multiple RP and feeding problems increased the odds of eating problems at 20 and 56 months. Persistent RP and feeding problems were predictive of deficits in preschool adaptive behaviour and social skills. In addition, sex differences were found.

CONCLUSIONS

Multiple RP and feeding problems had the highest stability. Persistent RP were predictive of adverse social and adaptive behaviour. Understanding of the aetiology may help to prevent persistent RP.

Crying and feeding problems in infancy and cognitive outcome in preschool children born at risk: a prospective population study

OBJECTIVE

To investigate whether regulatory problems, i.e., crying and feeding problems in infants older than 3 months of age, predict cognitive outcome in preschool children born at risk even when controlled for confounding factors.

METHODS

A prospective longitudinal study of children born in a geographically defined area in Germany. N = 4427 children of 6705 eligible survivors (66%) participated at all 4 assessment points (neonatal, 5, 20, and 56 months of age). Excessive crying and feeding problems were assessed at 5 months. Mental development was measured with the Griffiths Scale at 20 months, and cognitive assessments were conducted at 56 months. Neonatal complications, neurological, and psychosocial factors were controlled as confounders in structural equation modeling and analyses of variance.

RESULTS

One in 5 infants suffered from single crying or feeding problems, and 2% had multiple regulatory problems, i.e., combined crying and feeding problems at 5 months. In girls, regulatory problems were directly predictive of lower cognition at 56 months, even when controlled for confounders, whereas in boys, the influence on cognition at 56 months was mediated by delayed mental development at 20 months. Both in boys and girls, shortened gestational age, neonatal neurological complications, and poor parent-infant relationship were predictive of regulatory problems at 5 months and lower cognition at 56 months.

CONCLUSION

Excessive crying and feeding problems in infancy have a small but significant adverse effect on cognitive development.