Table 2.
Characteristics of the studies included in the review with a genetics and epigenetics focus.
| Citation Number | Article | Target Population | Methods | Results | ||||
|---|---|---|---|---|---|---|---|---|
| Age | Sample Size | Sample Characteristics | EA Measure | Additional Variables | Evidence of Reliability | |||
| [58] | Reichl et al. (2019) | Child age: M = 8.02 years, SD = 1.57 Mothers age: M = 39.28 years, SD = 5.71 |
193 mother–child dyads | Mothers excluded if they had neurological diseases, severe physical or mental disabilities, or if met criteria for an emotional-unstable, anxious-avoidant or antisocial personality disorder. Children excluded if they met the criteria for an autistic disorder or in case of an intelligence score below 70. |
Maternal sensitivity assessed with the sensitivity scale of the emotional availability (EA) scales (Biringen 2008). During two situations (free play; dealing with a hardly solvable puzzle task), mothers were asked to interact with their child without the attendance of any other person. | Analyzed three polymorphisms (rs53576, rs1042778, rs2254298) of the OXTR gene and plasma oxytocin | Inter-rater reliability, ICC ≥ 0.81 | Of the three analyzed polymorphisms (rs53576, rs1042778, rs2254298) of the OXTR gene and plasma oxytocin, only the rs53576 was associated with mothers’ parenting behavior, specifically with maternal sensitivity; rs2254298 significantly moderated relations between mothers’ experiences of childhood adversity and parenting behavior; significant relations for mothers homozygous for the G allele; G allele of the rs2254298 was related to increased plasma oxytocin levels |
| [59] | Lecompte et al. (2021) | Mother age: ≥18 years | 16 mother–child dyads | Gestational weeks: 12–14 weeks gestation and pregnant with a single baby | Five minutes of free play with parent and child: filmed and coded with the emotional availability scales | Separation–reunion procedure for preschool-age children; buccal swab for children’s DNA methylation analyses using the Oragene TMOG-250 collection kit; child methylation data at the follow-up time-point from the the OXTR exon 3 genomic region area | Interrater reliability, ICC = 0.51–0.71, sensitivity (.71), structuring (0.54). | Lower maternal sensitivity associated with more controlling caregiving behaviors; less maternal structuring associated with more controlling punitive behaviors; hypomethylation of the OXTR gene associated with greater maternal structuring behaviors and with more child controlling caregiving behaviors; no interaction effect found of OXTR gene as a moderator in the association between interactive behaviors and child controlling behaviors |
| [60] | Lewis et al. (2020) | Child age: M = 8.5 years, SD = 0.45 | N = 96 sub-sample of monozygotic twins | Monozygotic twins: 51% male; 50% Non-Hispanic white, 14.6% Hispanic/Latinx, 8.3% African American, 4.2% Asian American) |
EA measured with a 28-item, abridged version of the EA self-report. Items were rated on a five-point Likert scale from “almost never” to “almost always” (asked separately for each twin). Higher scores indicated higher mother-reported EA in the parent–child relationship |
General health composite using items from the parent-reported MacArthur health and behavior questionnaire (HBQ) (Essex et al., 2002) Buccal cells were collected with Mawi iSWAB DNA collection tubes (Mawi DNA Technologies LLC, Hayward, CA) |
Cronbach’s alpha was 0.721 and 0.806 at 1 and 2.5 years, respectively | Parental EA at 1 year old was related to multiple immune gene methylations in monozygotic twins at 8 years of age. Twin pairs with discordant health, compared to pairs with similar health, had more differences in immune gene methylation |