Childhood infections and autism spectrum disorders and/or intellectual disability: a register-based cohort study

Variants in HCFC1 and MN1 genes causing intellectual disability in two Pakistani families

BACKGROUND

Intellectual disability (ID) is a neurodevelopmental condition affecting around 2% of children and young adults worldwide, characterized by deficits in intellectual functioning and adaptive behavior. Genetic factors contribute to the development of ID phenotypes, including mutations and structural changes in chromosomes. Pathogenic variants in the HCFC1 gene cause X-linked mental retardation syndrome, also known as Siderius type X-linked mental retardation. The MN1 gene is necessary for palate development, and mutations in this gene result in a genetic condition called CEBALID syndrome.

METHODS

Exome sequencing was used to identify the disease-causing variants in two affected families, A and B, from various regions of Pakistan. Affected individuals in these two families presented ID, developmental delay, and behavioral abnormalities. The validation and co-segregation analysis of the filtered variant was carried out using Sanger sequencing.

RESULTS

In an X-linked family A, a novel hemizygous missense variant (c.5705G > A; p.Ser1902Asn) in the HCFC1 gene (NM_005334.3) was identified, while in family B exome sequencing revealed a heterozygous nonsense variant (c.3680 G > A; p. Trp1227Ter) in exon-1 of the MN1 gene (NM_032581.4). Sanger sequencing confirmed the segregation of these variants with ID in each family.

CONCLUSIONS

The investigation of two Pakistani families revealed pathogenic genetic variants in the HCFC1 and MN1 genes, which cause ID and expand the mutational spectrum of these genes.

The causal association between maternal depression, anxiety, and infection in pregnancy and neurodevelopmental disorders among 410 461 children: a population study using quasi-negative control cohorts and sibling analysis

BACKGROUND

To address if the long-standing association between maternal infection, depression/anxiety in pregnancy, and offspring neurodevelopmental disorder (NDD) is causal, we conducted two negative-control studies.

METHODS

Four primary care cohorts of UK children (pregnancy, 1 and 2 years prior to pregnancy, and siblings) born between 1 January 1990 and 31 December 2017 were constructed. NDD included autism/autism spectrum disorder, attention-deficit/hyperactivity disorder, intellectual disability, cerebral palsy, and epilepsy. Maternal exposures included depression/anxiety and/or infection. Maternal (age, smoking status, comorbidities, body mass index, NDD); child (gender, ethnicity, birth year); and area-level (region and level of deprivation) confounders were captured. The NDD incidence rate among (1) children exposed during or outside of pregnancy and (2) siblings discordant for exposure in pregnancy was compared using Cox-regression models, unadjusted and adjusted for confounders.

RESULTS

The analysis included 410 461 children of 297 426 mothers and 2 793 018 person-years of follow-up with 8900 NDD cases (incidence rate = 3.2/1000 person years). After adjustments, depression and anxiety consistently associated with NDD (pregnancy-adjusted HR = 1.58, 95% CI 1.46-1.72; 1-year adj. HR = 1.49, 95% CI 1.39-1.60; 2-year adj. HR = 1.62, 95% CI 1.50-1.74); and to a lesser extent, of infection (pregnancy adj. HR = 1.16, 95% CI 1.10-1.22; 1-year adj. HR = 1.20, 95% CI 1.14-1.27; 2-year adj. HR = 1.19, 95% CI 1.12-1.25). NDD risk did not differ among siblings discordant for pregnancy exposure to mental illness HR = 0.97, 95% CI 0.77-1.21 or infection HR = 0.99, 95% CI 0.90-1.08.

CONCLUSIONS

Maternal risk appears to be unspecific to pregnancy: our study provided no evidence of a specific, and therefore causal, link between in-utero exposure to infection, common mental illness, and later development of NDD.

The Association Between Children's Autism Spectrum Disorders and Central Nervous System Infections: Using a Nationwide Claims Database

Several studies have reported an association of autism spectrum disorder (ASD) with central nervous system (CNS) infections and intrauterine infections; however, the results remain unclear. This study aimed to examine this issue using an extensive national database. Utilizing JMDC medical claims database, we conducted a retrospective cohort study of children with at least three years of follow-up from birth, ensuring the mother's information was available. The focus was on the relationship between ASD incidence and exposures like viral meningitis/encephalitis, bacterial meningitis, and intrauterine infections. Cox proportional hazards was used to calculate hazard ratios (HRs) with covariates such as presence of maternal history of mental illness, preterm, low birth weight, respiratory and cardiac disorder, epilepsy, and cranial malformations. Sensitivity analysis was performed on sibling and multiple birth cohorts to adjust for genetic factors. Out of 276,195 mother-child pairs, bacterial meningitis was observed in 1326 (0.5%), viral meningitis/encephalitis in 6066 (2.2%), intrauterine infection in 3722 (1.3%), and ASD in 14,229 (5.2%) children. The adjusted HRs (95% confidence interval, p value) for ASD were 1.40 (1.25-1.57, p < 0.001), 1.14 (1.02-1.26, p = 0.013), and 1.06 (0.87-1.30, p = 0.539) for viral meningitis/encephalitis, intrauterine infection, and bacterial meningitis, respectively. After sensitivity analysis, the HRs for viral meningitis/encephalitis and ASD remained significantly high. Viral meningitis/encephalitis may be an independent risk factor for ASD. Awareness of this risk among healthcare professionals can lead to early intervention and potentially improved outcomes for affected children.

Strategies for dissecting the complexity of neurodevelopmental disorders

Neurodevelopmental disorders (NDDs) are associated with a wide range of clinical features, affecting multiple pathways involved in brain development and function. Recent advances in high-throughput sequencing have unveiled numerous genetic variants associated with NDDs, which further contribute to disease complexity and make it challenging to infer disease causation and underlying mechanisms. Herein, we review current strategies for dissecting the complexity of NDDs using model organisms, induced pluripotent stem cells, single-cell sequencing technologies, and massively parallel reporter assays. We further highlight single-cell CRISPR-based screening techniques that allow genomic investigation of cellular transcriptomes with high efficiency, accuracy, and throughput. Overall, we provide an integrated review of experimental approaches that can be applicable for investigating a broad range of complex disorders.

Exposure to Antibiotics and Neurodevelopmental Disorders: Could Probiotics Modulate the Gut-Brain Axis?

In order to develop properly, the brain requires the intricate interconnection of genetic factors and pre-and postnatal environmental events. The gut-brain axis has recently raised considerable interest for its involvement in regulating the development and functioning of the brain. Consequently, alterations in the gut microbiota composition, due to antibiotic administration, could favor the onset of neurodevelopmental disorders. Literature data suggest that the modulation of gut microbiota is often altered in individuals affected by neurodevelopmental disorders. It has been shown in animal studies that metabolites released by an imbalanced gut-brain axis, leads to alterations in brain function and deficits in social behavior. Here, we report the potential effects of antibiotic administration, before and after birth, in relation to the risk of developing neurodevelopmental disorders. We also review the potential role of probiotics in treating gastrointestinal disorders associated with gut dysbiosis after antibiotic administration, and their possible effect in ameliorating neurodevelopmental disorder symptoms.

Association of maternal autoimmune disease and early childhood infections with offspring autism spectrum disorder: A population-based cohort study

The aim of this study was to examine potential synergistic effects between maternal autoimmune disease and early childhood infections and their association with autism spectrum disorder (ASD) in offspring. Both exposures have been associated with increased risk of ASD in previous studies, but potential synergistic effects remain underexplored. We conducted a population-based cohort study of singleton children born at term gestation (37-41 weeks) in New South Wales, Australia from January 2002 to December 2008. Maternal autoimmune diagnoses and childhood infections before age 2 years were identified from linked maternal and child hospital admissions, and ASD diagnoses by age 9 years were identified from linked disability services data. Multivariable logistic regression assessed the association between each exposure and ASD and additive interaction between exposures, controlling for potential confounders. A total of 18,451 children exposed to maternal autoimmune disease were propensity score matched (1:2) to 36,902 unexposed children. Any maternal autoimmune disease (adjusted odds ratio (aOR) 1.25, 95% confidence interval (CI) 1.07-1.47) and any childhood infection before age 2 years (aOR 1.38, 95% CI 1.15-1.67) were each associated with ASD. However, there was no evidence of additive interaction between the two exposures (relative excess risk due to interaction [RERI] 0.128, 95% CI -0.418-0.675) resulting in increased odds of ASD in offspring. Future studies could examine potential interactions between other sources of maternal immune activation and childhood infection and impact on ASD and other neurodevelopmental disorders.

COVID-19-induced psychosis: two case reports and narrative literature review

Introduction: SARS-CoV-2 infection might be presented in many various specific and non-specific manifest and symptoms from different systems. Also, the psychotic symptoms are documented but the explanation for their pathophysiology remains debatable and a complex matter. The main objective of this paper is to present cases of patients without a history of psychiatric disorders who developed the first episode of psychosis during the SARS-CoV-2 infection.

Material and methods: Two cases of not-related patients with no previous psychiatric history developed psychotic episodes during COVID-19 infection. In both cases chronologically first they experienced symptoms of infection, secondly, delusions and psychomotor agitation that required psychiatric hospitalization. Full remission was observed after antipsychotic treatment in both cases.

Results: Even though the pathophysiology of the post-COVID-19 psychiatric symptoms remains unclear, some reports that indicate associations between the infection and the onset of such symptoms. The infection itself, by the induction of cytokine storm followed by the excessive release of pro-inflammatory cytokines, is considered to stimulate the potential onset of the psychosis, however, other factors such as medications used during treatment (with a particular emphasis on glucocorticosteroids) or psychological factors should be considered as well.

Conclusions: Patients infected with SARS-CoV-2 might develop serious psychotic episodes even without a prior psychiatric history. Besides, psychiatric symptoms might be the first the even the only manifestations associated with the active SARSCoV-2 infection which seems to be very challenging especially in cases of rapid psychotic episodes without any clear respiratory symptoms.

Maternal pregnancy-related infections and autism spectrum disorder-the genetic perspective

Autism spectrum disorder (ASD) refers to a group of neurodevelopmental disorders which include deficits in behavior, social interaction and communication. ASD has a complex genetic architecture, and it is also influenced by certain environmental exposures. Both types of predisposing factors may be related to immunological mechanisms, involving, for example, immune system genes and infections. Past studies have shown an association between infections occurring during the pregnancy in the mother and increased risk of ASD in the child, an observation which has received recent support from experimental animal studies of ASD-like behavior. The aim of this study was to study the genetic contribution to this effect. We employed genetic correlation analyses across potential ASD subtypes stratified on the basis of maternal pregnancy-related infections within the iPSYCH ASD case-cohort sample, as well as a case-case GWAS. We validated the trends of the genetic correlation analyses observed in our sample using GWAS summary statistics from the PGC ASD study (excluding iPSYCH). The genetic correlation between ASD with a history of maternal pregnancy-related infections and ASD without a history of maternal infections in iPSYCH was r_g = 0.3811. We obtained a similar estimate between the former and the PGC ASD phenotype (r_g = 0.3997). Both estimates are lower compared to the genetic correlation between ASD without a history of maternal infections and the PGC ASD phenotype (r_g = 0.6735), and between ASD with a history of maternal infections occurring only more than 2 months following childbirth and the PGC ASD phenotype (r_g = 0.6293). Additionally, we observed genetic variance between the two main ASD phenotypes using summary statistics from the case-case GWAS in iPSYCH (h²_cc = 0.1059), indicating genome-wide differences between the phenotypes. Our results suggest potentially different etiologies of ASD based on a history of maternal pregnancy-related infections, which may, in part, be genetic. This highlights the relevance of maternal pregnancy-related infections to genetic studies of ASD and provides new insights into the molecular underpinnings of ASD.