The Gestalt of functioning in autism revisited: First revision of the International Classification of Functioning, Disability and Health Core Sets.

LAY ABSTRACT: Autistic people experience individual strengths and challenges as well as barriers and facilitators in their environment. All of these factors contribute to how well autistic people can cope in everyday life, fulfill the roles they choose, and meet their needs. The World Health Organization has developed a system aiming to capture the many factors within people (like how someone thinks and feels) and outside of people (things around a person) that influence their daily living, called the International Classification of Functioning, Disability and Health. The International Classification of Functioning, Disability and Health can be used for different purposes in research and practice to assess people's situations and plan support measures. Previously in 2019, the International Classification of Functioning, Disability and Health was adapted to autism by developing so-called Core Sets, which are shorter International Classification of Functioning, Disability and Health versions for use in specific conditions. Here, we present the first revisions of the International Classification of Functioning, Disability and Health Core Sets for autism, based on research, development results, and community feedback. Some factors influencing daily life for autistic people were added to the Core Sets, and other factors deemed less relevant were removed. Changes were also made in Core Sets designed for different age groups (0-5, 6-16, and ⩾17 years). Particularly, contents for sensory processing (like smell, touch, seeing, hearing) were added. We recommend these updated Core Sets for future use in autism research and practice. These changes to the Core Sets after 4 years indicate that there should be ongoing updates based on research and experience from practice and involvement of stakeholders.

Deficiency of the Heterogeneous Nuclear Ribonucleoprotein U locus leads to delayed hindbrain neurogenesis.

Genetic variants affecting Heterogeneous Nuclear Ribonucleoprotein U (HNRNPU) have been identified in several neurodevelopmental disorders (NDDs). HNRNPU is widely expressed in the human brain and shows the highest postnatal expression in the cerebellum. Recent studies have investigated the role of HNRNPU in cerebral cortical development, but the effects of HNRNPU deficiency on cerebellar development remain unknown. Here, we describe the molecular and cellular outcomes of HNRNPU locus deficiency during in vitro neural differentiation of patient-derived and isogenic neuroepithelial stem cells with a hindbrain profile. We demonstrate that HNRNPU deficiency leads to chromatin remodeling of A/B compartments, and transcriptional rewiring, partly by impacting exon inclusion during mRNA processing. Genomic regions affected by the chromatin restructuring and host genes of exon usage differences show a strong enrichment for genes implicated in epilepsies, intellectual disability, and autism. Lastly, we show that at the cellular level HNRNPU downregulation leads to an increased fraction of neural progenitors in the maturing neuronal population. We conclude that the HNRNPU locus is involved in delayed commitment of neural progenitors to differentiate in cell types with hindbrain profile.

Camouflaging in Autism: Age Effects and Cross-Cultural Validation of the Camouflaging Autistic Traits Questionnaire (CAT-Q).

Given that camouflaging has been suggested to contribute to delayed diagnosis and mental health problems among autistic people, validated measures of the construct are needed. This study describes the psychometric evaluation of the Swedish adaptation of the self-reported Camouflaging Autistic Traits Questionnaire (CAT-Q) in autistic (n = 100) and general population (n = 539) samples aged 10 to 83 years. Analyses indicated good-to-excellent internal consistency and test-retest reliability. Construct validity was supported by autistic participants scoring higher than non-autistic, and autistic females scoring higher than autistic males on the measure. Also as expected, camouflaging was associated with theoretically linked traits, including autistic behaviors and depressive symptoms. On the other hand, the factor structure of the original CAT-Q did not provide a good fit in the Swedish data set, and validity issues were found, particularly in children younger than 15 years, warranting further investigation of the construct validity of the scale. Different age trajectories were observed, where camouflaging behaviors decreased during adulthood in non-autistic people but remained at an elevated level among autistic people.

Association of cumulative early medical factors with autism and autistic symptoms in a population-based twin sample.

Although highly heritable, environment also contributes to the etiology of autism spectrum disorder (ASD), with several specific environmental factors previously suggested. A registry-linked population-based twin cohort of 15,701 pairs (586 individuals with an ASD diagnosis), was established within the Child and Adolescent Twin Study in Sweden. Participants were evaluated for autistic symptoms at age 9 using the Autism-Tics, ADHD and other Comorbidities parental interview. A series of binary cut-offs indicated whether participants scored over various ASD symptom percentiles. Three early medical factors previously associated with ASD, beyond familial confounding (low birth weight, congenital malformations and perinatal hypoxia), were summed up creating an individual cumulative exposure load. A series of unconditional logistic regressions between all individuals and conditional regressions within twin pairs were performed for each outcome and exposure level. Between all individuals increasing cumulative early exposure loads were associated with increasing risk of ASD diagnosis (OR 3.33 (95%CI 1.79-6.20) for three exposures) and autistic symptoms (ranging from OR 2.12 (1.57-2.86) for three exposures at the 55th symptom percentile cut-off to OR 3.39 (2.2-5.24) at the 95th). Within twin pairs, the association between three exposures and an ASD diagnosis remained similar, but not statistically significant (OR 2.39 (0.62-9.24)). Having a higher load of early cumulative exposure was consistently associated with autistic symptoms after adjusting for familial confounding and sex (OR 3.45 (1.66-7.15) to OR 7.36 (1.99-27.18)). This study gives support to the cumulative stress hypothesis of ASD, and the dimensional model regarding environmental exposures, after adjustment for familial confounding.

Nonshared environmental factors in the aetiology of autism and other neurodevelopmental conditions: a monozygotic co-twin control study.

BACKGROUND: A significant proportion of variation in likelihood of neurodevelopmental conditions (NDCs) has been attributed to nonshared environmental (NSE) factors, although it remains unclear which NSE factors pose specific risks for certain NDCs. METHODS: A monozygotic co-twin design was applied in a sample of 224 twins (mean age = 17.70 years, SD = 6.28) controlling for confounders such as genes and shared environment. Generalized estimating equation models were fitted, using perinatal and postnatal indications of NSEs as exposure, operationalized both as separate risk factors and as cumulative risk loads. Categorical and dimensional operationalizations of autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), intellectual disability and other NDCs were used as outcomes. RESULTS: Birth weight discordance was associated with dimensional autism and ADHD for the smaller twin, and medication during infancy was associated with dimensional autism. Among postnatal factors scarlet fever during early childhood was associated with lower IQ. Especially autism was associated with a greater cumulative perinatal or postnatal risk load. LIMITATIONS: When exploring the associations between each condition and specific NSEs the risk of being statistically underpowered increases. Hence, we limit the reported findings on specific indicators of NSEs to trait levels and present descriptive data for categorical NDCs. CONCLUSIONS: The findings support previous research by indicating an association between exposure to perinatal and postnatal risks and subsequent NDCs within twin pairs and suggest that autism may be especially linked to accumulative early environmental risks. The findings are potentially important for developmental outcomes prognoses and may inform targeted prevention and early interventions.

Eating Problems in Autistic Females and Males: A Co-twin Control Study.

This study investigated the association between autism and self-reported eating problems and the influence of gender on the association, in a sample of adolescent and adult twins (N = 192). Autistic traits and autism diagnosis were associated with both total and specific eating problems, including selective eating and sensory sensitivity during mealtimes. Interaction effects indicated a stronger association between autistic traits and total eating problems in females, as well as more difficulties with eating in social contexts among autistic females. In within-pair analyses, where unmeasured confounders including genes and shared environment are implicitly controlled for, the association was lost within monozygotic pairs, which might further indicate a genetic influence on the relationship between autism and eating problems.

The impact of atypical sensory processing on adaptive functioning within and beyond autism: The role of familial factors.

LAY ABSTRACT: Individuals diagnosed with autism tend to process sensory information differently than individuals without autism, resulting for instance in increased sensitivity to sounds or smells. This leads to challenges in everyday life and may restrict the individual's daily functioning. How direct this link is, however, is currently unclear. We investigated this question in 289 twins of whom 60 were diagnosed with autism and further 61 were diagnosed with other neurodevelopmental disorders. We looked at the association between unusual sensory processing and adaptive skills, both across individuals and within-twin pairs, testing whether individuals with higher levels of atypical sensory processing showed reduced adaptive skills compared to their twins. Since twins share 50%-100% of their genes and part of their environment (e.g. family background), associations within-twin pairs are free from effects of these familial factors. We found that an increased sensitivity to, as well as the avoiding of, sensory input (hyper-responsiveness) was linked to reduced adaptive skills across individuals-but not within-twin pairs. We also found an association between the degree to which individuals seek for sensory input (sensation seeking) and reduced adaptive skills, but only in individuals diagnosed with autism. The results suggest that sensory hyper-responsiveness has negative effects on individuals' general ability to function, but that this link is influenced by familial factors and hence not direct. In addition, sensation seeking behaviors might have a negative impact on adaptive skills specifically in autistic individuals.

A co-twin-control study of altered sensory processing in autism.

LAY ABSTRACT: Individuals diagnosed with autism often describe that they process sensory information differently from others, and many experience sensory issues as problematic. For instance, an increased sensitivity to smells or sounds can make participating in social settings challenging. While sensory issues are now part of the diagnostic criteria for autism, they also co-occur with other psychiatric diagnoses such as attention deficit hyperactivity disorder and anxiety disorders. It is unclear to what extent the relationship between autism and alterations in sensory processing are due to genetics or environment. In addition, more research is needed on how autism, as compared to other diagnoses, is associated with sensory issues. Using a twin study, we found that genetic factors influenced self-reported reactivity to sensory stimuli in autism while environmental factors influenced other sensory issues (e.g. difficulties in detecting or differentiating sensory input). Hence, sensory hyper-reactivity might be an early onset core feature of autism, while other domains of alterations in sensory processing might develop later, influenced by the environment. Moreover, autism was more strongly associated with sensory issues related to increased sensitivity/reactivity as compared to other psychiatric diagnoses. However, attention deficit hyperactivity disorder was more strongly related to deficits in detecting/differentiating sensory stimuli and with an increased drive to seek sensory input. Our results indicate that sensory issues are not specific to autism, but that some aspects of altered sensory processing are more relevant for autism than for other diagnoses.