Polymorphisms in the maternal sex steroid pathway are associated with behavior problems in male offspring

Parental genetic effects on the offspring's phenotype without transmission of the gene itself-pathophysiology and clinical evidence

Parental genes can influence the phenotype of their offspring through genomic-epigenomic interactions even without the direct inheritance of specific parental genotypes. Maternal genetic variations can affect the ovarian and intrauterine environments and potentially alter lactation behaviors, impacting offspring nutrition and health outcomes independently of the fetal genome. Similarly, paternal genetic changes can affect the endocrine system and vascular functions in the testes, influencing sperm quality and seminal fluid composition. These changes can initiate early epigenetic modifications in sperm, including alterations in microRNAs, tRNA-derived small RNAs (tsRNAs), and DNA methylation patterns. These epigenetic modifications might induce further changes in target organs of the offspring, leading to modified gene expression and phenotypic outcomes without transmitting the original parental genetic alterations. This review presents clinical evidence supporting this hypothesis and discusses the potential underlying molecular mechanisms. Parental gene-offspring epigenome-offspring phenotype interactions have been observed in neurocognitive disorders and cardio-renal diseases.

Parental sex-dependent effects of either maternal or paternal eNOS deficiency on the offspring's phenotype without transmission of the parental eNOS deficiency to the offspring

Background: Preclinical animal studies and clinical studies indicate that both maternal as well as paternal genetic alterations/gene defects might affect the phenotype of the next-generation without transmissions of the affected gene. Currently, the question of whether the same genetic defect present in the mother or father leads to a similar phenotype in the offspring remains insufficiently elucidated. Methods: In this head-to-head study, we crossbred female and male mice with heterozygous endothelial eNOS knockout (eNOS+/-) with male and female wild-type (wt) mice, respectively. Subsequently, we compared the phenotype of the resulting wt offspring with that of wt offspring born to parents with no eNOS deficiency. Results: Wt female offspring of mothers with heterozygous eNOS showed elevated liver fat accumulation, while wt male offspring of fathers with heterozygous eNOS exhibited increased fasting insulin, heightened insulin levels after a glucose load, and elevated liver glycogen content. By quantitative mass-spectrometry it was shown that concentrations of six serum metabolites (lysoPhosphatidylcholine acyl C20:3, phosphatidylcholine diacyl C36:2, phosphatidylcholine diacyl C38:1, phosphatidylcholine acyl-alkyl C34:1, phosphatidylcholine acyl-alkyl C36:3, and phosphatidylcholine acyl-alkyl C42:5 (PC ae C42:5) as well as four liver carbon metabolites (fructose 6-phosphate, fructose 1,6-bisphosphate, glucose 6-phosphate and fumarate) were different between wt offspring with eNOS+/- mothers and wt offspring with eNOS+/- fathers. Importantly, fumarate was inversely correlated with the liver fat accumulation in female offspring with eNOS+/- mothers and increased liver glycogen in offspring of both sexes with eNOS+/- fathers. The qRT-PCR results revealed that the gene expression patterns were different between wt offspring with eNOS+/- mothers and those offspring with eNOS+/- fathers. Different gene expression patterns were correlated with different observed phenotypic changes in male/female offspring born to mothers or fathers with a heterozygous eNOS genotype. Conclusion: The identical parental genetic alteration (heterozygous eNOS deficiency), without being passed on to the offspring, results in distinct metabolic, liver phenotype, and gene expression pattern variations depending on whether the genetic alteration originated from the father or the mother.

Paternal eNOS deficiency in mice affects glucose homeostasis and liver glycogen in male offspring without inheritance of eNOS deficiency itself

AIMS/HYPOTHESIS

It was shown that maternal endothelial nitric oxide synthase (eNOS) deficiency causes fatty liver disease and numerically lower fasting glucose in female wild-type offspring, suggesting that parental genetic variants may influence the offspring's phenotype via epigenetic modifications in the offspring despite the absence of a primary genetic defect. The aim of the current study was to analyse whether paternal eNOS deficiency may cause the same phenotype as seen with maternal eNOS deficiency.

METHODS

Heterozygous (+/-) male eNOS (Nos3) knockout mice or wild-type male mice were bred with female wild-type mice. The phenotype of wild-type offspring of heterozygous male eNOS knockout mice was compared with offspring from wild-type parents.

RESULTS

Global sperm DNA methylation decreased and sperm microRNA pattern altered substantially. Fasting glucose and liver glycogen storage were increased when analysing wild-type male and female offspring of +/- eNOS fathers. Wild-type male but not female offspring of +/- eNOS fathers had increased fasting insulin and increased insulin after glucose load. Analysing candidate genes for liver fat and carbohydrate metabolism revealed that the expression of genes encoding glucocorticoid receptor (Gr; also known as Nr3c1) and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (Pgc1a; also known as Ppargc1a) was increased while DNA methylation of Gr exon 1A and Pgc1a promoter was decreased in the liver of male wild-type offspring of +/- eNOS fathers. The endocrine pancreas in wild-type offspring was not affected.

CONCLUSIONS/INTERPRETATION

Our study suggests that paternal genetic defects such as eNOS deficiency may alter the epigenome of the sperm without transmission of the paternal genetic defect itself. In later life wild-type male offspring of +/- eNOS fathers developed increased fasting insulin and increased insulin after glucose load. These effects are associated with increased Gr and Pgc1a gene expression due to altered methylation of these genes.

Vertical exposition to Luffa operculata extract deregulates behavior and hypothalamus neurotransmitters in juvenile rats

ETHNOPHARMACOLOGICAL RELEVANCE

Luffa operculata (L.) Cogn (Cucurbitaceae) is a traditional plant popularly used in the abortion induction, against sinusitis and is toxic.

AIM OF THE STUDY

To verify the influence of the aqueous extract obtained from the dry fruit of L. operculata (BNE) on the male rats vertically exposed to a subabortive dose of BNE, by evaluating alterations in behavior and neurochemical features in hypothalamus, striatum and frontal cortex, at a juvenile age, after receiving a stress challenge given by the use of the "New York subway stress" technique (NYS).

MATERIALS AND METHODS

Pregnant female rats (F0 generation) received 1.0 mg/kg BNE, or distilled water (100 mL/kg), by gavage, between gestation days GD17 and GD21. The pups were weaned at PND21 and were kept up to PND60 (juvenile age) in controlled environmental conditions. Four groups were obtained: control (CG), experimental (EG), stress control (SCG) and stress experimental (SEG) After being stressed, the animals were behavioral screened for in the open field (OF) and in light-dark box (LDB) apparatuses. They were euthanized, and the liver, kidneys and brain were removed for both macroscopic and microscopic analyses, and for quantification of vanillylmandelic acid (VMA), norepinephrine (NE), dopamine (DA) and its metabolite, 3,4-dihydroxyphenylacetic acid (DOPAC) and the serotonin (5-HT) and its metabolite 5-hydroxyindolylacetic acid (5-HIAA) were accessed in the hypothalamus, frontal cortex and striatum.

RESULTS AND DISCUSSION

although most of the behavior changes were due to the stress challenge, the rats spent more time in the dark side of the LDB and were less likely to explore the light side, indicating that the treatment with BNE induced to fear. Interferences of BNE over behavior were due to impairment of VMA, NE, 5-HT and DA and increasing of DOPAC in the hypothalamus, and an increase of 5-HIAA in the frontal cortex, indicating alterations in the hypothalamic-hypophysis-adrenal axis (HHAA). No macroscopic or histopathological changes were observed in the liver, kidneys, or brain, although GFAP was diminished in the SCG, as expected for stressed rats.

CONCLUSION

the vertical exposition of juvenile rats to BNE led to the manifestation of fear and to a down regulation of the hypothalamic-hypophysis-adrenal axis.

Prenatal sex hormones and behavioral outcomes in children

Abnormal sex hormone levels in utero have been associated with child behavioral problems, but it is unclear if normal variation in prenatal sex hormones is associated with subsequent behavior in childhood. We assessed maternal sex hormones, including serum estrone (E1), estradiol (E2), estriol (E3), free testosterone (FT), and total testosterone (TT), during early pregnancy (gestational week 6-21 (mean = 11.1)) and evaluated child behavior at ages 4-5 using the Behavioral Assessment System for Children (BASC-2) and Social Responsiveness Scale (SRS-2) in 404 mother/child pairs (211 girls, 193 boys) within The Infant Development and Environment Study, a multi-site pregnancy cohort study. Associations between hormones and composite scores were evaluated using multiple linear regressions in both sexes combined, and separate models assessed effect modification by sex with the addition of interaction terms. A 10-fold increase in maternal FT or TT was associated in both sexes with a 4.3-point (95 % CI: 0.5, 8.2) or 4.4-point (0.8, 8.0) higher BASC-2 internalizing composite T score, respectively. In addition, a 10-fold increase in FT or TT was associated with a 3.8-point (0.04, 7.5) or 4.0-point (0.5, 7.5) higher behavioral symptoms index composite score. In models evaluating effect modification by sex, a 10-fold increase in E1 was associated with a 4.3-point (1.2, 7.4) decrease in adaptive skills composite score in girls only (interaction p = 0.04). We observed associations between testosterone and internalizing behaviors and behavioral symptoms index in both sexes, as well as a female-specific association between E1 and adaptive skills. Sex hormones during pregnancy may play a key role in influencing later-life behavior, and additional studies should further examine different periods of susceptibility to hormonal signals.

Congenital Abnormalities of the Male Reproductive System and Risk of Autism Spectrum Disorders

Androgens have an extensive influence on brain development in regions of the brain that are relevant for autism spectrum disorder (ASD), yet their etiological involvement remains unclear. Hypospadias (abnormal positioning of the urethral opening) and cryptorchidism (undescended testes) are 2 relatively common male birth defects that are strongly associated with prenatal androgen deficiencies. Having either disorder is a proxy indicator of atypical gestational androgen exposure, yet the association between these disorders and autism has not been extensively studied. We analyzed male singleton live births (n = 224,598) occurring from January 1, 1999, through December 31, 2013, in a large Israeli health-care organization. Boys with autism, cryptorchidism, and hypospadias were identified via International Classification of Diseases, Ninth Revision, codes, with further verification of autism case status by review of medical records. In multivariable-adjusted analyses, the odds ratio for ASD among boys with either condition was 1.62 (95% confidence interval (CI): 1.44, 1.82). The odds ratio for boys with cryptorchidism only was 1.55 (95% CI: 1.34, 1.78), and that for boys with hypospadias only was 1.65 (95% CI: 1.38, 1.98). ASD risk was not elevated among unaffected brothers of hypospadias or cryptorchidism cases, despite familial aggregation of all 3 conditions, providing some indication for the possibility of pregnancy-specific risk factors driving the observed associations. Results suggest that in-utero hypoandrogenicity could play a role in ASD etiology.

Maternal hormonal milieu influence on fetal brain development

An adverse maternal hormonal environment during pregnancy can be associated with abnormal brain growth. Subtle changes in fetal brain development have been observed even for maternal hormone levels within the currently accepted physiologic ranges. In this review, we provide an update of the research data on maternal hormonal impact on fetal neurodevelopment, giving particular emphasis to thyroid hormones and glucocorticoids. Thyroid hormones are required for normal brain development. Despite serum TSH appearing to be the most accurate indicator of thyroid function in pregnancy, maternal serum free T4 levels in the first trimester of pregnancy are the major determinant of postnatal psychomotor development. Even a transient period of maternal hypothyroxinemia at the beginning of neurogenesis can confer a higher risk of expressive language and nonverbal cognitive delays in offspring. Nevertheless, most recent clinical guidelines advocate for targeted high-risk case finding during first trimester of pregnancy despite universal thyroid function screening. Corticosteroids are determinant in suppressing cell proliferation and stimulating terminal differentiation, a fundamental switch for the maturation of fetal organs. Not surprisingly, intrauterine exposure to stress or high levels of glucocorticoids, endogenous or synthetic, has a molecular and structural impact on brain development and appears to impair cognition and increase anxiety and reactivity to stress. Limbic regions, such as hippocampus and amygdala, are particularly sensitive. Repeated doses of prenatal corticosteroids seem to have short-term benefits of less respiratory distress and fewer serious health problems in offspring. Nevertheless, neurodevelopmental growth in later childhood and adulthood needs further clarification. Future studies should address the relevance of monitoring the level of thyroid hormones and corticosteroids during pregnancy in the risk stratification for impaired postnatal neurodevelopment.

Sex steroid hormones and sex hormone binding globulin levels, CYP17 MSP AI (-34T:C) and CYP19 codon 39 (Trp:Arg) variants in children with developmental stuttering

Developmental stuttering is known to be a sexually dimorphic and male-biased speech motor control disorder. In the present case-control study, we investigated the relationship between developmental stuttering and steroid hormones. Serum levels of testosterone, dihydrotestosterone (DHT), dehydroepiandrosterone (DHEA), oestradiol, progesterone, cortisol, and sex hormone binding globulin (SHBG), as well as the 2nd/4th digit ratio (2D:4D), an indicator of prenatal testosterone level, were compared between children who stutter (CWS) and children who do not stutter (CWNS). Moreover, two SNPs (CYP17 -34 T:C (MSP AI) and CYP19 T:C (Trp:Arg)) of cytochrome P450, which is involved in steroid metabolism pathways, were analysed between the groups. Our results showed significantly higher levels of testosterone, DHT, and oestradiol in CWS in comparison with CWNS. The severity of stuttering was positively correlated with the serum levels of testosterone, DHEA, and cortisol, whereas no association was seen between the stuttering and digit ratio, progesterone, or SHBG. The CYP17CC genotype was significantly associated with the disorder.

Maternal Polycystic Ovary Syndrome and Risk for Attention-Deficit/Hyperactivity Disorder in the Offspring

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) is the most common childhood neurodevelopmental disorder, and boys are two to three times more likely to develop ADHD. Maternal polycystic ovary syndrome (PCOS), a common metabolic disorder associated with excess circulating androgens, has been associated with increased risk for autism spectrum disorder in the offspring. In this study, we aimed to investigate whether maternal PCOS increases the risk for ADHD in the offspring.

METHODS

We conducted a matched case-control study using health and population data registers for all children born in Sweden from 1984 to 2008. Maternal PCOS was defined by ICD-coded register diagnosis. The outcome of ADHD was defined as an ICD-coded register diagnosis of ADHD and/or registered prescription of medications to treat ADHD. A total of 58,912 ADHD cases (68.8% male) were identified and matched to 499,998 unaffected controls by sex and birth month and year.

RESULTS

Maternal PCOS increased the odds of offspring ADHD by 42% after adjustment for confounders (odds ratio [OR], 1.42; 95% confidence interval [CI], 1.26-1.58). Exclusion of ADHD cases with comorbid autism spectrum disorder attenuated but did not explain the relationship (OR, 1.34; 95% CI, 1.18-1.52). The risk was somewhat elevated for ADHD with comorbid autism spectrum disorder (OR, 1.76; 95% CI, 1.37-2.26). The risk for ADHD was higher among obese mothers with PCOS (OR, 1.68; 95% CI, 1.31-2.17) and was highest among obese mothers with PCOS and other features of metabolic syndrome (OR, 2.59; 95% CI, 1.02-6.58).

CONCLUSIONS

This study provides evidence that maternal PCOS may subtly influence the neurodevelopment of the offspring, resulting in increased risk for neurodevelopmental disorders such as ADHD.

Estrogen Signaling as a Therapeutic Target in Neurodevelopmental Disorders

Estrogens, the primary female sex hormones, were originally characterized through their important role in sexual maturation and reproduction. However, recent studies have shown that estrogens play critical roles in a number of brain functions, including cognition, learning and memory, neurodevelopment, and adult neuroplasticity. A number of studies from both clinical as well as preclinical research suggest a protective role of estrogen in neurodevelopmental disorders including autism spectrum disorder (ASD) and schizophrenia. Alterations in the levels of estrogen receptors have been found in subjects with ASD or schizophrenia, and adjunctive estrogen therapy has been shown to be effective in enhancing the treatment of schizophrenia. This review summarizes the findings on the role of estrogen in the pathophysiology of neurodevelopmental disorders with a focus on ASD and schizophrenia. We also discuss the potential of estrogen as a therapeutic target in the above disorders.

Aggressive behavior in humans: Genes and pathways identified through association studies

Aggressive behavior has both genetic and environmental components. Many association studies have been performed to identify genetic factors underlying aggressive behaviors in humans. In this review we summarize the previous work performed in this field, considering both candidate gene (CGAS) and genome-wide association studies (GWAS), excluding those performed in samples where the primary diagnosis is a psychiatric or neurological disorder other than an aggression-related phenotype. Subsequently, we have studied the enrichment of pathways and functions in GWAS data. The results of our searches show that most CGAS have identified associations with genes involved in dopaminergic and serotonergic neurotransmission and in hormone regulation. On the other hand, GWAS have not yet identified genome-wide significant associations, but top nominal findings are related to several signaling pathways, such as axon guidance or estrogen receptor signaling, and also to neurodevelopmental processes and synaptic plasticity. Future studies should use larger samples, homogeneous phenotypes and standardized measurements to identify genes that underlie aggressive behaviors in humans. © 2016 Wiley Periodicals, Inc.

Genetics of aggressive behavior: An overview

The Research Domain Criteria (RDoC) address three types of aggression: frustrative non-reward, defensive aggression and offensive/proactive aggression. This review sought to present the evidence for genetic underpinnings of aggression and to determine to what degree prior studies have examined phenotypes that fit into the RDoC framework. Although the constructs of defensive and offensive aggression have been widely used in the animal genetics literature, the human literature is mostly agnostic with regard to all the RDoC constructs. We know from twin studies that about half the variance in behavior may be explained by genetic risk factors. This is true for both dimensional, trait-like, measures of aggression and categorical definitions of psychopathology. The non-shared environment seems to have a moderate influence with the effects of shared environment being unclear. Human molecular genetic studies of aggression are in an early stage. The most promising candidates are in the dopaminergic and serotonergic systems along with hormonal regulators. Genome-wide association studies have not yet achieved genome-wide significance, but current samples are too small to detect variants having the small effects one would expect for a complex disorder. The strongest molecular evidence for a genetic basis for aggression comes from animal models comparing aggressive and non-aggressive strains or documenting the effects of gene knockouts. Although we have learned much from these prior studies, future studies should improve the measurement of aggression by using a systematic method of measurement such as that proposed by the RDoC initiative.

ADHD-like behavior in a patient with hypothalamic hamartoma

We report a male patient with hypothalamic hamartoma (HH) who manifested central precocious puberty (CPP) at 4 years of age. Gonadotropin-releasing hormone (GnRH) analogue treatment was started at 6 years of age and his pubertal signs were suppressed. At 9 years of age, the patient was emotionally unstable, aggressive, and antisocial. He had severe attention deficit hyperactivity disorder (ADHD)-like behavior and conduct disorder. No seizure activity was observed. GnRH analogue treatment was discontinued for 8 months from 9 years and 4 months of age due to his mother's illness. During this period sexual urges were observed. Treatment with daily methylphenidate markedly improved his behavioral problems. However, his sexual urges were not suppressed until 3 months after the GnRH analogue treatment was restarted. The present case is unique because the patient's behavioral problems were observed despite the parahypothalamic type of HH and absence of seizures. This case is also rare because behavioral problems were observed without seizures, and no ADHD cases with hamartoma have been reported previously. Recently, clinical studies have described an association between psychiatric morbidity, including ADHD, and hyperandrogenism disorders. Our patient's ADHD-like symptoms might be due to hyperandrogenism. In such cases, GnRH analogue with methylphenidate could be effective for improving ADHD-like symptoms.

Stuttering in relation to anxiety, temperament, and personality: review and analysis with focus on causality

Anxiety and emotional reactions have a central role in many theories of stuttering, for example that persons who stutter would tend to have an emotionally sensitive temperament. The possible relation between stuttering and certain traits of temperament or personality were reviewed and analyzed, with focus on temporal relations (i.e., what comes first). It was consistently found that preschool children who stutter (as a group) do not show any tendencies toward elevated temperamental traits of shyness or social anxiety compared with children who do not stutter. Significant group differences were, however, repeatedly reported for traits associated with inattention and hyperactivity/impulsivity, which is likely to reflect a subgroup of children who stutter. Available data is not consistent with the proposal that the risk for persistent stuttering is increased by an emotionally reactive temperament in children who stutter. Speech-related social anxiety develops in many cases of stuttering, before adulthood. Reduction of social anxiety in adults who stutter does not in itself appear to result in significant improvement of speech fluency. Studies have not revealed any relation between the severity of the motor symptoms of stuttering and temperamental traits. It is proposed that situational variability of stuttering, related to social complexity, is an effect of interference from social cognition and not directly from the emotions of social anxiety. In summary, the studies in this review provide strong evidence that persons who stutter are not characterized by constitutional traits of anxiety or similar constructs.

EDUCATIONAL OBJECTIVES

This paper provides a review and analysis of studies of anxiety, temperament, and personality, organized with the objective to clarify cause and effect relations. Readers will be able to (a) understand the importance of effect size and distribution of data for interpretation of group differences; (b) understand the role of temporal relations for interpretation of cause and effect; (c) discuss the results of studies of anxiety, temperament and personality in relation to stuttering; and (d) discuss situational variations of stuttering and the possible role of social cognition.

Cognitive functions of regularly cycling women may differ throughout the month, depending on sex hormone status; a possible explanation to conflicting results of studies of ADHD in females

Attention Deficit/Hyperactivity Disorder (ADHD) is considered as a model of neuro-developmental cognitive function. ADHD research previously studied mainly males. A major biological distinction between the genders is the presence of a menstrual cycle, which is associated with variations in sex steroid hormone levels. There is a growing body of literature showing that sex hormones have the ability to regulate intracellular signaling systems that are thought to be abnormal in ADHD. Thus, it is conceivable to believe that this functional interaction between sex hormones and molecules involved with synaptic plasticity and neurotransmitter systems may be associated with some of the clinical characteristics of women with ADHD. In spite of the impact of sex hormones on major neurotransmitter systems of the brain in a variety of clinical settings, the menstrual cycle is usually entered to statistical analyses as a nuisance or controlled for by only testing male samples. Evaluation of brain structure, function and chemistry over the course of the menstrual cycle as well as across the lifespan of women (premenarche, puberty, cycling period, premenopause, postmenopause) is critical to understanding sex differences in both normal and aberrant mental function and behavior. The studies of ADHD in females suggest confusing and non-consistent conclusions. None of these studies examined the possible relationship between phase of the menstrual cycle, sex hormones levels and ADHD symptoms. The menstrual cycle should therefore be taken into consideration in future studies in the neurocognitive field since it offers a unique opportunity to understand whether and how subtle fluctuations of sex hormones and specific combinations of sex hormones influence neuronal circuits implicated in the cognitive regulation of emotional processing. The investigation of biological models involving the role of estrogen, progesterone, and other sex steroids has the potential to generate new and improved diagnostic and treatment strategies that could change the course of cognitive-behavioral disorders such as ADHD.

Associations between polymorphisms in sex steroid related genes and autistic-like traits

Sex differences in psychiatric disorders are common, which is particularly striking in autism spectrum disorders (ASDs) that are four times more prevalent in boys. High levels of testosterone during early development have been hypothesized to be a risk factor for ASDs, supported by several studies showing fetal testosterone levels, as well as indirect measures of prenatal androgenization, to be associated with ASDs and autistic-like traits (ALTs). Further, the importance of sex steroid related genes in ASDs is supported by studies reporting associations between polymorphisms in genes involved in sex steroid synthesis/metabolism and ASDs and ALTs. The aim of the present study was to investigate possible associations between 29 single nucleotide polymorphisms (SNPs) in eight genes related to sex steroids and autistic features. Individuals included in the study belong to a subset (n=1771) from The Child and Adolescent Twin Study in Sweden (CATSS), which are all assessed for ALTs. For two SNPs, rs2747648 located in the 3'-UTR of ESR1 encoding the estrogen receptor alpha and rs523349 (Leu89Val) located in SRD5A2 encoding 5-alpha-reductase, type 2, highly significant associations with ALTs were found in boys and girls, respectively. The results of the present study suggest that SNPs in sex steroid related genes, known to affect gene expression (rs2747648 in ESR1) and enzymatic activity (Leu89Val in SRD5A2), seem to be associated with ALTs in a general population. In conclusion, the current findings provide further support for a role of sex steroids in the pathophysiology of ASDs.