Maternal C-Reactive Protein Concentration in Early Pregnancy and Child Autistic Traits in the General Population

Association between interpregnancy interval and risk of autism spectrum disorder: a systematic review and Bayesian network meta-analysis

Although the risk of autism spectrum disorder (ASD) has been reported to be associated with interpregnancy intervals (IPIs), their association remains debatable due to inconsistent findings in existing studies. Therefore, the present study aimed to explore their association. PubMed, Embase, Web of Science, and the Cochrane Library were systematically retrieved up to May 25, 2022. An updated search was performed on May 25, 2023, to encompass recent studies. The quality of the included studies was assessed using the Newcastle-Ottawa Scale (NOS). Our primary outcome measures were expressed as adjusted odds ratios (ORs). Given various control measures for IPI and diverse IPI thresholds in the included studies, a Bayesian network meta-analysis was performed. Eight studies were included, involving 24,865 children with ASD and 2,890,289 children without ASD. Compared to an IPI of 24 to 35 months, various IPIs were significantly associated with a higher risk of ASD (IPIs < 6 months: OR = 1.63, 95% CI 1.53-1.74, n = 5; IPIs of 6-11 months: OR = 1.50, 95% CI 1.42-1.59, n = 4; IPIs of 12-23 months: OR = 1.19, 95% CI 1.12-1.23, n = 10; IPIs of 36-59 months: OR = 0.96, 95% CI 0.94-0.99, n = 2; IPIs of 60-119 months: OR = 1.15, 95% CI 1.10-1.20, n = 4; IPIs > 120 months: OR = 1.57, 95% CI 1.43-1.72, n = 4). After adjusting confounding variables, our analysis delineated a U-shaped restricted cubic spline curve, underscoring that both substantially short (< 24 months) and excessively long IPIs (> 72 months) are significantly correlated with an increased risk of ASD.  Conclusion: Our analysis indicates that both shorter and longer IPIs might predispose children to a higher risk of ASD. Optimal childbearing health and neurodevelopmental outcomes appear to be associated with a moderate IPI, specifically between 36 and 60 months. What is Known: • An association between autism spectrum disorder (ASD) and interpregnancy intervals (IPIs) has been speculated in some reports. • This association remains debatable due to inconsistent findings in available studies. What is New: • Our study delineated a U-shaped restricted cubic spline curve, suggesting that both shorter and longer IPIs predispose children to a higher risk of ASD. • Optimal childbearing health and neurodevelopmental outcomes appear to be associated with a moderate IPI, specifically between 36 and 60 months.

Interleukin 15 modulates the effects of poly I:C maternal immune activation on offspring behaviour

Maternal infections during pregnancy are linked with an increased risk for disorders like Autism Spectrum Disorder and schizophrenia in the offspring. Although precise mechanisms are still unclear, clinical and preclinical evidence suggest a strong role for maternal immune activation (MIA) in the neurodevelopmental disruptions caused by maternal infection. Previously, studies using the Polyinosinic:Polycytidylic (Poly I:C) MIA preclinical model showed that cytokines like Interleukin 6 (Il6) are important mediators of MIA's effects. In this study, we hypothesized that Il15 may similarly act as a mediator of Poly I:C MIA, given its role in the antiviral immune response. To test this hypothesis, we induced Poly I:C MIA at gestational day 9.5 in wildtype (WT) and Il15^−/− rat dams and tested their offspring in adolescence and adulthood. Poly I:C MIA and Il15 knockout produced both independent and synergistic effects on offspring behaviour. Poly I:C MIA decreased startle reactivity in adult WT offspring but resulted in increased adolescent anxiety and decreased adult locomotor activity in Il15^−/− offspring. In addition, Poly I:C MIA led to genotype-independent effects on locomotor activity and prepulse inhibition. Finally, we showed that Il15^−/− offspring exhibit distinct phenotypes that were unrelated to Poly I:C MIA including altered startle reactivity, locomotion and signal transduction in the auditory brainstem. Overall, our findings indicate that the lack of Il15 can leave offspring either more or less susceptible to Poly I:C MIA, depending on the phenotype in question. Future studies should examine the contribution of fetal versus maternal Il15 in MIA to determine the precise developmental mechanisms underlying these changes.

•

Poly I:C MIA decreases startle reactivity in adult WT but not Il15^−/− offspring.

•

Il15^−/− offspring exposed to Poly I:C MIA show altered PPI and open field exploration.

•

Il15^−/− rats exhibit distinct behavioural phenotypes independent from MIA.

Maternal levels of acute phase proteins in early pregnancy and risk of autism spectrum disorders in offspring

Previous research supports a contribution of early-life immune disturbances in the etiology of autism spectrum disorders (ASD). Biomarker studies of the maternal innate (non-adaptive) immune status related to ASD risk have focused on one of the acute phase proteins (APP), C-reactive protein (CRP), with conflicting results. We evaluated levels of eight different APP in first-trimester maternal serum samples, from 318 mothers to ASD cases and 429 mothers to ASD-unaffected controls, nested within the register-based Stockholm Youth Cohort. While no overall associations between high levels of APP and ASD were observed, associations varied across diagnostic sub-groups based on co-occurring conditions. Maternal levels of CRP in the lowest compared to the middle tertile were associated with increased risk of ASD without ID or ADHD in offspring (OR = 1.92, 95% CI 1.08-3.42). Further, levels of maternal ferritin in the lowest (OR = 1.78, 95% CI 1.18-2.69) and highest (OR = 1.64, 95% CI 1.11-2.43) tertiles were associated with increased risk of any ASD diagnosis in offspring, with stronger associations still between the lowest (OR = 3.81, 95% CI 1.91-7.58) and highest (OR = 3.36, 95% CI 1.73-6.53) tertiles of ferritin and risk of ASD with ID. The biological interpretation of lower CRP levels among mothers to ASD cases is not clear but might be related to the function of the maternal innate immune system. The finding of aberrant levels of ferritin conferring risk of ASD-phenotypes indicates a plausibly important role of iron during neurodevelopment.

Maternal tobacco smoking and offspring autism spectrum disorder or traits in ECHO cohorts

Given inconsistent evidence on preconception or prenatal tobacco use and offspring autism spectrum disorder (ASD), this study assessed associations of maternal smoking with ASD and ASD-related traits. Among 72 cohorts in the Environmental Influences on Child Health Outcomes consortium, 11 had ASD diagnosis and prenatal tobaccosmoking (n = 8648). and 7 had Social Responsiveness Scale (SRS) scores of ASD traits (n = 2399). Cohorts had diagnoses alone (6), traits alone (2), or both (5). Diagnoses drew from parent/caregiver report, review of records, or standardized instruments. Regression models estimated smoking-related odds ratios (ORs) for diagnoses and standardized mean differences for SRS scores. Cohort-specific ORs were meta-analyzed. Overall, maternal smoking was unassociated with child ASD (adjusted OR, 1.08; 95% confidence interval [CI], 0.72-1.61). However, heterogeneity across studies was strong: preterm cohorts showed reduced ASD risk for exposed children. After excluding preterm cohorts (biased by restrictions on causal intermediate and exposure opportunity) and small cohorts (very few ASD cases in either smoking category), the adjusted OR for ASD from maternal smoking was 1.44 (95% CI, 1.02-2.03). Children of smoking (versus non-smoking) mothers had more ASD traits (SRS T-score + 2.37 points, 95% CI, 0.73-4.01 points), with results homogeneous across cohorts. Maternal preconception/prenatal smoking was consistently associated with quantitative ASD traits and modestly associated with ASD diagnosis among sufficiently powered United States cohorts of non-preterm children. Limitations resulting from self-reported smoking and unmeasured confounders preclude definitive conclusions. Nevertheless, counseling on potential and known risks to the child from maternal smoking is warranted for pregnant women and pregnancy planners. LAY SUMMARY: Evidence on the association between maternal prenatal smoking and the child's risk for autism spectrum disorder has been conflicting, with some studies reporting harmful effects, and others finding reduced risks. Our analysis of children in the ECHO consortium found that maternal prenatal tobacco smoking is consistently associated with an increase in autism-related symptoms in the general population and modestly associated with elevated risk for a diagnosis of autism spectrum disorder when looking at a combined analysis from multiple studies that each included both pre- and full-term births. However, this study is not proof of a causal connection. Future studies to clarify the role of smoking in autism-like behaviors or autism diagnoses should collect more reliable data on smoking and measure other exposures or lifestyle factors that might have confounded our results.

Sensory filtering disruption caused by poly I:C - Timing of exposure and other experimental considerations

Maternal immune activation (MIA) in response to infection during pregnancy has been linked through various epidemiological and preclinical studies to an increased risk of neurodevelopmental disorders such as autism spectrum disorder (ASD) and schizophrenia in exposed offspring. Sensory filtering disruptions occur in both of these disorders and are typically measured using the acoustic startle response in both humans and rodents. Our study focuses on characterizing the baseline reactivity, habituation and prepulse inhibition (PPI) of the acoustic startle response following exposure to MIA. We induced MIA using polyinosinic: polycytidylic acid (poly I:C) at gestational day (GD) 9.5 or 14.5, and we tested sensory filtering phenotypes in adolescent and adult offspring. Our results show that startle reactivity was robustly increased in adult GD9.5 but not GD14.5 poly I:C offspring. In contrast to some previous studies, we found no consistent changes in short-term habituation, long-term habituation or prepulse inhibition of startle. Our study highlights the importance of MIA exposure timing and discusses sensory filtering phenotypes as they relate to ASD, schizophrenia and the poly I:C MIA model. Moreover, we analyze and discuss the potential impact of between- and within-litter variability on behavioural findings in poly I:C studies.

Maternal prenatal choline and inflammation effects on 4-year-olds' performance on the Wechsler Preschool and Primary Scale of Intelligence-IV

Maternal gestational inflammation from infection, obesity, depression, and adverse childhood experiences negatively affects offspring cognitive development. Choline is a key nutrient in fetal brain development. We investigated whether higher maternal plasma choline concentrations have a positive association with offspring cognition, specifically processing speed, in the presence of inflammation. Forty-eight children were evaluated at 4 years of age. Processing Speed Composite Score on the Wechsler Preschool & Primary Scales of Intelligence was the principal outcome. Maternal C-reactive protein (CRP), a marker of inflammation, and choline plasma concentration had been measured at 16 weeks' gestation. Choline concentrations >7.07μM were compared to lower levels. Mothers with lower choline levels reported more depression and stress. Head circumference was larger for neonates of mothers with higher choline levels. In analyses with maternal CRP, higher maternal choline was associated with higher offspring Processing Speed Composite Scores for both sexes. For males, higher maternal choline competed with the negative association of maternal CRP on Processing Speed. Higher Processing Speed was related to the child's behavioral ratings, with fewer Withdrawn Problems on the Child Behavior Checklist 1 ½-5 years at 4 years and higher Infant Behavior Questionnaire Orienting/Regulation at 3 months of age, consistent with persistent developmental effects. Higher processing speed and decreased problems in social withdrawal are positively associated with prenatal maternal choline. Both lower processing speed and social withdrawal problems are precursors to later mental difficulties. Choline supplementation in pregnancy may mitigate effects of maternal inflammation that contribute to problems in offspring's' cognition and behavior.

Male fetus susceptibility to maternal inflammation: C-reactive protein and brain development

BACKGROUND

Maternal inflammation in early pregnancy has been identified epidemiologically as a prenatal pathogenic factor for the offspring's later mental illness. Early newborn manifestations of the effects of maternal inflammation on human fetal brain development are largely unknown.

METHODS

Maternal infection, depression, obesity, and other factors associated with inflammation were assessed at 16 weeks gestation, along with maternal C-reactive protein (CRP), cytokines, and serum choline. Cerebral inhibition was assessed by inhibitory P50 sensory gating at 1 month of age, and infant behavior was assessed by maternal ratings at 3 months of age.

RESULTS

Maternal CRP diminished the development of cerebral inhibition in newborn males but paradoxically increased inhibition in females. Similar sex-dependent effects were seen in mothers' assessment of their infant's self-regulatory behaviors at 3 months of age. Higher maternal choline levels partly mitigated the effect of CRP in male offspring.

CONCLUSIONS

The male fetal-placental unit appears to be more sensitive to maternal inflammation than females. Effects are particularly marked on cerebral inhibition. Deficits in cerebral inhibition 1 month after birth, similar to those observed in several mental illnesses, including schizophrenia, indicate fetal developmental pathways that may lead to later mental illness. Deficits in early infant behavior follow. Early intervention before birth, including prenatal vitamins, folate, and choline supplements, may help prevent fetal development of pathophysiological deficits that can have life-long consequences for mental health.

Autism spectrum disorder and severe social impairment associated with elevated plasma interleukin-8

BACKGROUND

Autism spectrum disorder (ASD) is a neurodevelopmental disorder with an unclear etiology and pathophysiology. Previous studies have indicated that the dysregulation of cytokines may be involved in the pathogenesis of ASD and that the levels of cytokines may serve as potential biomarkers of this disorder.

METHODS

The current study employed a family triad-based case-control design to study the levels of plasma cytokines in families with ASD (n = 45 triads) and controls (n = 38 triads) with a Human Cytokine Twenty-Five-Plex Kit. The Social Responsiveness Scale (SRS) was used to measure social impairment of ASD children.

RESULTS

After controlling for the levels of parental cytokines, we identified that interferon-α (IFN-α), interleukin-7 (IL-7), IL-8, IFN-γ-inducible protein-10, and macrophage inflammatory protein-1β were associated with ASD, and IL-8 was the only cytokine also associated with the levels of both parental cytokines in the offspring-parents regression analysis and three subdomains of SRS (social awareness, cognition, and motivations) in the children with ASD. The receiver operating characteristic curve showed that the log-transformed IL-8 level discriminated children with autism from controls with an area under the curve of 0.858 (95% confidence interval: 0.777-0.939).

CONCLUSIONS

Our study suggests that IL-8 is a potential biomarker for ASD and may be involved in the pathogenesis of ASD.

IMPACT

The study suggests that IL-8 is a promising biomarker for ASD and may be involved in the pathogenesis of ASD. Only a very few studies have reported the parental cytokine levels. The significant strength of this article is that we applied the family triad-based approach to explore cytokine levels in families with autism and controls. There are no objective biomarkers, making the accurate diagnosis, prognostic prediction and effective treatment difficult, and our study provides promising results.

C reactive protein elevation among children or among mothers' of children with autism during pregnancy, a review and meta-analysis

OBJECTIVE

To evaluate if children with ASD, or mothers of ASD children have elevated CRP during pregnancy.

BACKGROUND

Autism spectrum disorder (ASD) is a neuro developmental disorder with incidence of 1 in 68 children occur in all racial, ethnic, and socioeconomic groups. Economic burden between $11.5 billion - $60.9 billion and family average medical expenditures of $4110-$6200 per year. Conflicting evidence exist about role of maternal CRP during pregnancy with ASD child.

METHODS

Searches on database; Pubmed, Medline, Embase and google scholar using key words; C reactive protein (CRP), Maternal CRP, ASD, autism, autistic disorder, Inflammation. All English-language studies published between 1960 and 2019 pertaining to CRP and ASD. All Studies which provided data on CRP levels during pregnancy (mCRP) of Mothers of offsprings with ASD and (mCRP) of mothers of normal subjects were selected. Data were extracted in the form of odd ratios of having high mCRP in mothers of children with ASD versus mCRP of mothers of normal controls. Since these odd ratios were adjusted, therefore no Meta regression were attempted. Significant heterogeneity was found; therefore, random effect model was employed.

RESULTS

Review of CRP levels in children with ASD showed higher level in children with ASD than control, although different methodology and absence of numerical data did not allow metanalysis. Regarding mCRP and ASD, three studies were identified that provide data on mCRP and ASD. Four datasets were created from these 3 studies as the study by Zerbo et al. provided data in 2 subsets. Total number of subjects were 5258 (Brown, N = 677, Zerbo = 416, Koks = 4165) extracted data from these studies was pooled for analysis. Random effect model was employed and substantial heterogeneity among the studies was observed 11. Mothers of children with ASD have adjusted Odd ratio of 1.02 (0.948 to 1.103, I2 = 75, P = 0.558) to have high mCRP comparing mothers of control.

CONCLUSION

Mothers of children with ASD appear not to have elevated CRP during pregnancy. Children with ASD appear to have higher levels of CRP levels.

Maternal Immune Activation by Poly I:C as a preclinical Model for Neurodevelopmental Disorders: A focus on Autism and Schizophrenia

Maternal immune activation (MIA) in response to a viral infection during early and mid-gestation has been linked through various epidemiological studies to a higher risk for the child to develop autism or schizophrenia-related symptoms.. This has led to the establishment of the pathogen-free poly I:C-induced MIA animal model for neurodevelopmental disorders, which shows relatively high construct and face validity. Depending on the experimental variables, particularly the timing of poly I:C administration, different behavioural and molecular phenotypes have been described that relate to specific symptoms of neurodevelopmental disorders such as autism spectrum disorder and/or schizophrenia. We here review and summarize epidemiological evidence for the effects of maternal infection and immune activation, as well as major findings in different poly I:C MIA models with a focus on poly I:C exposure timing, behavioural and molecular changes in the offspring, and characteristics of the model that relate it to autism spectrum disorder and schizophrenia.

Higher Gestational Choline Levels in Maternal Infection Are Protective for Infant Brain Development

OBJECTIVE

To assess whether maternal choline decreases effects of mothers' infections on fetal brain circuit development and on expression of infant behavior at 1 year of age.

STUDY DESIGN

A cross-sectional study was conducted in a public hospital obstetrics and midwifery service, with prenatal assessments of maternal infection, C-reactive protein, and choline level and postnatal assessments of cerebral neuronal inhibition in 162 newborns. At 1 year, 136 parents completed reports of their child's behavior.

RESULTS

Maternal infection at 16 weeks of gestation, experienced by 41% of mothers, raised mean maternal C-reactive protein (d' = 0.47, P = .002) and decreased the development of cerebral inhibition of auditory response at 1 month of age (d' = 0.39, P < .001). Decreased newborn cerebral inhibition manifested as decreased behavioral self-regulation at 1 year. Greater choline levels in mothers with infections were associated with improved newborn inhibition of auditory cerebral response, mitigating the effect of infection (β = -0.34 [95% CI, -5.35 to -0.14], P = .002). At 1 year of age, children of mothers with infection and greater gestational choline levels had improved development of self-regulation, approaching the level of children of mothers without infection (β = 0.29 [95% CI 0.05-0.54], P = .03).

CONCLUSIONS

Greater maternal choline, recommended by the American Medical Association as a prenatal supplement, is associated with greater self-regulation among infants who experienced common maternal infections during gestation. Behavioral problems with diminished self-regulation often lead to referrals to pediatricians and might lead to later mental illness.

Maternal C-reactive protein and cytokine levels during pregnancy and the risk of selected neuropsychiatric disorders in offspring: A systematic review and meta-analysis

The pathophysiology of neuropsychiatric disorders is unclear. Increasing evidence has suggested maternal immune system dysregulation may be implicated in offspring's early brain development and related to an increased risk of neuropsychiatric disorders in offspring. The primary objective of this meta-analysis was to investigate the association of maternal CRP and cytokine levels with offspring's neuropsychiatric disorders. We identified relevant studies following a search of PubMed, Web of Science, EMbase database between January 1971 and February 2018. A meta-analysis was performed on studies which reported the association of prenatal maternal peripheral blood concentrations of CRP and cytokines with offspring's neuropsychiatric disorders. Results were reported according to PRISMA statement. Fifteen studies (six for maternal CRP, nine for maternal cytokines) were included in the meta-analysis, of which 80% were of high methodological quality. Random-effect meta-analysis showed that increasing maternal CRP (OR = 1.31, 95% CI 1.11-1.55, SMD = 0.15, 95% CI 0.06-0.24, P < 0.01), pro-inflammatory cytokine interleukin (IL)-8 (OR = 1.64, 95% CI 1.06-2.55, SMD = 0.27, 95% CI 0.03-0.52, P = 0.03) and anti-inflammatory cytokine IL-10 (OR = 2.16, 95% CI 1.30-3.59, SMD = 0.43, 95% CI 0.14-0.71, P < 0.01) were significantly associated with schizophrenia in offspring. The finding of our meta-analysis has identified significantly altered maternal CRP and cytokine concentrations in schizophrenia, strengthening evidence of maternal immune system dysregulation in neuropsychiatric disorders where inflammatory signals dominate.

Family history of immune conditions and autism spectrum and developmental disorders: Findings from the study to explore early development

Numerous studies have reported immune system disturbances in individuals with autism and their family members; however, there is considerable variability in findings with respect to the specific immune conditions involved, their timing, and the family members affected and little understanding of variation by autism subphenotype. Using data from the Study to Explore Early Development (SEED), a multi-site case-control study of children born 2003-2006 in the United States, we examined the role of family history of autoimmune diseases, asthma, and allergies in autism spectrum disorder (ASD) as well as other developmental disorders (DD). We investigated maternal immune conditions during the pregnancy period, as well as lifetime history of these conditions in several family members (mother, father, siblings, and study child). Logistic regression analyses included 663 children with ASD, 984 children with DD, and 915 controls ascertained from the general population (POP). Maternal history of eczema/psoriasis and asthma was associated with a 20%-40% increased odds of both ASD and DD. Risk estimates varied by specific ASD subphenotypes in association with these exposures. In addition, children with ASD were more likely to have a history of psoriasis/eczema or allergies than POP controls. No association was observed for paternal history or family history of these immune conditions for either ASD or DD. These data support a link between maternal and child immune conditions and adverse neurodevelopmental outcomes, and further suggest that associations may differ by ASD phenotype of the child. Autism Research 2019, 12: 123-135. © 2018 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Using data from a large multi-site study in the US-the Study to Explore Early Development-we found that women with a history of eczema/psoriasis and asthma are more likely to have children with ASD or DD. In addition, children with ASD are more likely to have a history of psoriasis/eczema or allergies than typically developing children. These data support a link between maternal and child immune conditions and adverse neurodevelopmental outcomes.

Concentrations of immune marker in newborn dried blood spots and early childhood development: Results from the Upstate KIDS Study

BACKGROUND

Evidence shows cytokine dysregulation in children with developmental disabilities. The association between immune activity during the perinatal period and child development is less clear.

METHODS

We examined the relationship between newborn concentrations of immune markers and child development. Within Upstate KIDS, a population-based birth cohort (2008-2010, upstate New York), we assayed immune markers, which are postulated to have neuro-modulatory effects, in newborn dried blood spots (NDBS, n = 3038). Mothers completed the Ages & Stages Questionnaire© (ASQ) for their children repeatedly through age 36 months. At 30 and 36 months, mothers also reported whether their children received any developmental services. We used generalised linear mixed models adjusted for maternal and child characteristics to test associations.

RESULTS

Sixteen immune markers were associated with failing ASQ in unadjusted models. After full adjustment (for gestational age, mode of delivery, parity, pregnancy smoking, etc.), we observed that higher levels of 4 markers, including platelet-derived growth factor-AA (PDGF-AA, OR 0.77, 95% CI 0.67, 0.89), plasminogen activator inhibitor-1 (OR 0.80, 95% CI 0.68, 0.94), stromal cell derived factor-1 (OR 0.85, 95% CI 0.73, 0.98), and macrophage inflammatory protein-1beta (OR 0.87, 95% CI 0.77, 0.98) were associated with lower odds of ASQ failure. The associations did not exist if correction for multiple comparisons was performed, except for PDGF-AA. Analyses with developmental service use revealed similar null findings.

CONCLUSIONS

Immune marker concentrations in NDBS may not be associated with developmental delay in the general population. Newborn concentrations of growth factor PDGF-AA may be protective of developmental delay in childhood.

Gestational cytokine concentrations and neurocognitive development at 7 years

Gestational inflammation may contribute to brain abnormalities associated with childhood neuropsychiatric disorders. Limited knowledge exists regarding the associations of maternal cytokine levels during pregnancy with offspring neurocognitive development. We assayed the concentrations of five cytokines (interleukin (IL)-6, IL-1β, IL-8, tumor necrosis factor alpha (TNF-α), and IL-10) up to four times in the 2nd and 3rd trimesters of pregnancy using stored prenatal sera from 1366 participants in the New England Family Study (enrollment 1959-1966). Intelligence (IQ), academic achievement, and neuropsychological functioning of singleton offspring were assessed at age 7 years using standardized tests. We used linear mixed models with random effects to estimate the cumulative exposure to each cytokine during 2nd and 3rd trimesters, and then related cumulative cytokine exposure to a wide range of offspring neurocognitive outcomes. We found that children of women with higher levels of the pro-inflammatory cytokine, TNF-α, in the 2nd and 3rd trimesters had lower IQ (B = -2.51, 99% CI: -4.84,-0.18), higher problem scores in visual-motor maturity (B = 0.12, 99% CI: 0.001,0.24), and lower Draw-a-Person test scores (B = -1.28, 99% CI: -2.49,-0.07). Higher gestational levels of IL-8, another pro-inflammatory molecule, were associated with better Draw-a-Person test scores and tactile finger recognition scores. Other cytokines were not associated with our outcome of interest. The opposing directions of associations observed between TNF-α and IL-8 with childhood outcomes suggest pleiotropic effects of gestational inflammation across the domains of neurocognitive functioning. Although the path to psychopathological disturbances in children is no doubt multifactorial, our findings point to a potential role for immune processes in the neurocognitive development of children.

Genetic Syndromes, Maternal Diseases and Antenatal Factors Associated with Autism Spectrum Disorders (ASD)

Autism spectrum disorder (ASD) affecting about 1% of all children is associated, in addition to complex genetic factors, with a variety of prenatal, perinatal, and postnatal etiologies. In addition, ASD is often an important clinical presentation of some well-known genetic syndromes in human. We discuss these syndromes as well as the role of the more important prenatal factors affecting the fetus throughout pregnancy which may also be associated with ASD. Among the genetic disorders we find Fragile X, Rett syndrome, tuberous sclerosis, Timothy syndrome, Phelan-McDermid syndrome, Hamartoma tumor syndrome, Prader-Willi and Angelman syndromes, and a few others. Among the maternal diseases in pregnancy associated with ASD are diabetes mellitus (PGDM and/or GDM), some maternal autoimmune diseases like antiphospholipid syndrome (APLS) with anti-β2GP1 IgG antibodies and thyroid disease with anti-thyroid peroxidase (TPO) antibodies, preeclampsia and some other autoimmune diseases with IgG antibodies that might affect fetal brain development. Other related factors are maternal infections (rubella and CMV with fetal brain injuries, and possibly Influenza with fever), prolonged fever and maternal inflammation, especially with changes in a variety of inflammatory cytokines and antibodies that cross the placenta and affect the fetal brain. Among the drugs are valproic acid, thalidomide, misoprostol, and possibly SSRIs. β2-adrenergic receptor agonists and paracetamol have also lately been associated with increased rate of ASD but the data is too preliminary and inconclusive. Associations were also described with ethanol, cocaine, and possibly heavy metals, heavy smoking, and folic acid deficiency. Recent studies show that heavy exposure to pesticides and air pollution, especially particulate matter < 2.5 and 10 μm in diameter (PM2.5 and PM10) during pregnancy is also associated with ASD. Finally, we have to remember that many of the associations mentioned in this review are only partially proven, and not all are "clean" of different confounding factors. The associations described in this review emphasize again how little we know about the etiology and pathogenesis of ASD. It is obvious that we need more epidemiologic data to establish many of these associations, but if proven, they might be promising avenues for prevention.