Genetic and epigenetic effects on couple adjustment in context of romantic relationship: A scoping systematic review

Abstract

Introduction: Couples' relationships defined by a complex interaction between the two partners and their intrapersonal traits. Romantic; relationships and love are associated with marital satisfaction and stability, as well as couples' happiness and health. Personality traits influence romantic relationships and, personality influenced by genetical and non-genetically factors. The roles of non-genetically factors such as socioeconomic position and external appearance have revealed in determining the quality of romantic relationships. Methods: We; performed a scoping systematic review to assess the association between genetics and epigenetic factors and romantic relationship. Relevant articles were identified by PubMed, EMBASE, Web of Science, Scopus, and the APA PsycInfo searching between inception and 4 June 2022. Results: Different studies evaluated the associated polymorphisms in 15 different genes or chromosomal regions. In the first step; we classified them into four groups: (1) Oxytocin-related signaling pathway (OXTR, CD38, and AVPR1A); (2) Serotonin-related signaling pathway (SLC6A4, HTR1A, and HTR2A); (3) Dopamine and catecholamine-related signaling pathway (DRD1, DRD2, DRD4, ANKK1, and COMT); and (4) other genes (HLA, GABRA2, OPRM1, and Y-DNA haplogroup D-M55). Then, we evaluated and extracted significant polymorphisms that affect couple adjustment and romantic relationships. Discussion: Overall, the findings suggest that genetic and epigenetics variants play a key role in marital adjustment and romantic relationships over time.

Keywords: couple adjustment; epigenetics; genetics; marital adjustment; romantic relationship.

FIGURE 1

PRISMA flow diagram of study identification.

FIGURE 2

Oxytocin- related signaling pathway. Oxytocin receptors (OTR) stimulated by Oxytocin (OT; green circles). Then, the G_q/11 type GTP-binding protein and phospholipase C (PLC) are activated, leading to creation of inositol-1,4,5-trisphosphate (IP3) and diacylglycerol (DAG). This results in Ca²⁺ mobilization activation from IP₃-sensitive Ca²⁺ pools. CD38 activated by stimulated protein kinase C (PKC) and increases cADPR creation from β-NAD⁺ inside or outside cells. cADPR using a mechanism mentioned as Ca²⁺-induced Ca²⁺ release, mobilizes Ca²⁺ via cADPR-sensitive Ca²⁺ pools. cADPR triggers Ca²⁺ influx TRPM2 cation channels. TRPM2 channels can inhibit by 2-Aminoethoxydiphenyl borate (2-APB). TRPM2 facilitates Ca²⁺ influx, which also trigger Ca²⁺ mobilization through ryanodine receptor Ca²⁺ release channels as a cofactor together with cADPR. These Ca²⁺ intensification mechanisms increase Ca²⁺ ions and Ca²⁺ ions trigger OT release into the brain, which is an important factor for social memory and social behavior.

FIGURE 3

Serotonin-related signaling pathway; Dopamine and catecholamine-related signaling pathway. (A) Dopamine synthesis and signal transduction. The main metabolic pathway for dopamine synthesis has two steps. First, tyrosine hydroxylase can convert tyrosine to L-dopa and then L-dopa transforms to dopamine (not shown). Dopamine is transported by the monoamine transporter (VMAT2) from the cytosol to the vesicles in synaptic vesicles and is stored until it is released into the synaptic cleft. Dopamine degradation pathway involves monoamine oxidase (MAO) in the outer mitochondrial membrane. Dopamine receptors are present in both postsynaptic and presynaptic neurons (including dopamine transporters, DAT). Dopamine receptors belong to the GPCR superfamily associated with various types of G proteins. D1- and d2-like receptors are important receptors for dopamine signaling. These receptors are also crosstalks with other signaling pathways such as Gαq, Gβγ, DAG, IP3, CAMP, and MAPK-MEK-ERK. (B) 5-HT Synthesis and signal transduction. Tryptophan is the essential amino acid involved in the synthesis of 5-HT. In CNS l-tryptophan is hydroxylated to 5-hydroxytryptophan (5-HTP) by the enzyme tryptophan hydroxylase type 2 (TPH2). This is followed by subsequent decarboxylation THAT transforms 5-hydroxytryptophan into 5-hydroxytryptamine. 5-HT is transported by the monoamine transporter) VMAT2) into vesicles and storage. Like dopamine 5-HT can be degraded by monoamine oxidase (MAO) in the outer mitochondrial membrane. After released 5-HT it can engage with receptors. All 5-HTRs are heteroreceptors and postsynaptically expressed on non-serotonergic neurons and autoreceptors located presynaptically on the serotonergic neurons. 5-HT1A, B, D, E, F, 5-HT2A, B, C, 5-HT4, 5-HT5A, B, 5-HT6, and 5-HT7 receptors are classified as G protein-coupled receptors (GPCRs), while 5-HT3A, B, C, D, E receptors are ligand-gated ion channels. Upon ligand binding, the intracellular loop and C-terminal tail interact with specific G protein families, including Gαs, Gαi/o, Gαq/11, and leading to activated many signaling pathways such as DAG, IP3, CAMP, and MAPK-MEK-ERK.