Behavioral and biological divergence in monozygotic twin pairs discordant for autism phenotypes: A systematic review

Symptoms of autism in Williams syndrome: a transdiagnostic approach

Williams syndrome (WS) is associated with atypical social communication and cognition reminiscent of the behaviours observed in autism. Nonetheless, WS also differs significantly from autism, such as regarding social motivation, which is typically enhanced in WS and reduced in autism. This study sought to examine the conditions' transdiagnostic similarities and differences for autistic symptoms and social functioning, and their developmental trajectories, by comparing individuals with WS (n = 24) and those diagnosed with idiopathic autism (n = 24) and attention deficit hyperactivity disorder (ADHD; n = 24), aged 9 to 53 years, on measures of autism, social functioning, IQ and cooccurring psychiatric conditions. Although only 12.5% in the WS group met the criteria for an autism diagnosis, a majority exhibited distinct difficulties within social communication, social cognition, repetitive behaviours, and atypical sensory reactivity resembling autism. Conversely, elevated social motivation and a high number of social initiatives accompany these characteristics. No group differences in the developmental trajectories of autism symptoms were found. Our results demonstrate that autistic behaviours are more frequent in individuals with WS, than in individuals with idiopathic ADHD, and emphasize the need for clinical management of these behaviours.

Exploring Early Childhood Autism Spectrum Disorders: A Comprehensive Review of Diagnostic Approaches in Young Children

Autism spectrum disorders (ASD) encompass a diverse range of developmental disabilities characterized by pervasive deficiencies in socialization, communication, and the manifestation of behavioral issues. This review aims to clarify the diagnostic criteria for ASD, explore available diagnostic tools, evaluate biomedical examinations facilitating ASD diagnosis, and discuss the approach to screening assessments for ASD. ASDs are prevalent conditions, with a globally estimated prevalence of 7.6 cases per 100 (one in 132), based on a comprehensive review of epidemiological studies. The precise cause of autism and other ASDs remains unknown; however, genetic and environmental factors likely contribute. Common signs and symptoms shared among individuals with autism include restricted repetitive behaviors and learning disabilities. Standardized methods, such as the Diagnostic and Statistical Manual, Fifth Edition (DSM-5), diagnostic instruments, a thorough medical history, multiple physical examinations, laboratory investigations, neuroimaging, and screening tests, play a pivotal role in early autism diagnosis and intervention. ASD is a lifelong neurodevelopmental condition characterized by multiple deficits. Early detection is anticipated to have a positive impact on outcomes.

Deciduous tooth biomarkers reveal atypical fetal inflammatory regulation in autism spectrum disorder

Atypical regulation of inflammation has been proposed in the etiology of autism spectrum disorder (ASD); however, measuring the temporal profile of fetal inflammation associated with future ASD diagnosis has not been possible. Here, we present a method to generate approximately daily profiles of prenatal and early childhood inflammation as measured by developmentally archived C-reactive protein (CRP) in incremental layers of deciduous tooth dentin. In our discovery population, a group of Swedish twins, we found heightened inflammation in the third trimester in children with future ASD diagnosis relative to controls (n = 66; 14 ASD cases; critical window: -90 to -50 days before birth). In our replication study, in the US, we observed a similar increase in CRP in ASD cases during the third trimester (n = 47; 23 ASD cases; -128 to -21 days before birth). Our results indicate that the third trimester is a critical period of atypical fetal inflammatory regulation in ASD.

Emotion dysregulation in ADHD and other neurodevelopmental conditions: a co-twin control study

BACKGROUND

Emotion dysregulation (ED) is common in attention-deficit/hyperactivity disorder (ADHD) and often results in adverse outcomes. However, ED has been suggested as a transdiagnostic construct, why the specific association between ADHD and ED when adjusting for other mental health conditions needs further investigation. It is also important to determine the aetiological basis of the association between ADHD and ED to inform the theoretical conceptualization of ADHD.

METHOD

This study used a co-twin control design, including a sample of dizygotic (DZ) and monozygotic (MZ) twins (N = 389; 45.8% females, age = 8-31 years, MZ twin pairs 57.6%). ED was assessed using the dysregulation profile from the parent-rated Child Behaviour Checklist and its adult version. Regression analyses were used across individuals and within the pairs, while adjusting for diagnoses of autism, intellectual disability, other neurodevelopmental conditions and affective conditions.

RESULTS

ADHD was significantly associated with ED, even when adjusting for age, sex, attention problems and other mental health conditions, and was the diagnosis most strongly associated with ED. Within-pair analyses revealed that twins with ADHD had higher levels of ED compared to their co-twin without ADHD. This association remained within DZ twins and was non-significant in the MZ subsample, with non-overlapping confidence intervals between the DZ and MZ estimates.

CONCLUSION

ADHD is strongly and in part independently linked to ED, stressing the importance of early detection and treatment of emotional difficulties within this group. The findings from the within-pair analyses indicate a genetic influence on the association between ADHD and ED.