A systematic review of non-coding RNA genes with differential expression profiles associated with autism spectrum disorders

AIMS

To identify differential expression of shorter non-coding RNA (ncRNA) genes associated with autism spectrum disorders (ASD).

BACKGROUND

ncRNA are functional molecules that derive from non-translated DNA sequence. The HUGO Gene Nomenclature Committee (HGNC) have approved ncRNA gene classes with alignment to the reference human genome. One subset is microRNA (miRNA), which are highly conserved, short RNA molecules that regulate gene expression by direct post-transcriptional repression of messenger RNA. Several miRNA genes are implicated in the development and regulation of the nervous system. Expression of miRNA genes in ASD cohorts have been examined by multiple research groups. Other shorter classes of ncRNA have been examined less. A comprehensive systematic review examining expression of shorter ncRNA gene classes in ASD is timely to inform the direction of research.

METHODS

We extracted data from studies examining ncRNA gene expression in ASD compared with non-ASD controls. We included studies on miRNA, piwi-interacting RNA (piRNA), small NF90 (ILF3) associated RNA (snaR), small nuclear RNA (snRNA), small nucleolar RNA (snoRNA), transfer RNA (tRNA), vault RNA (vtRNA) and Y RNA. The following electronic databases were searched: Cochrane Library, EMBASE, PubMed, Web of Science, PsycINFO, ERIC, AMED and CINAHL for papers published from January 2000 to May 2022. Studies were screened by two independent investigators with a third resolving discrepancies. Data was extracted from eligible papers.

RESULTS

Forty-eight eligible studies were included in our systematic review with the majority examining miRNA gene expression alone. Sixty-four miRNA genes had differential expression in ASD compared to controls as reported in two or more studies, but often in opposing directions. Four miRNA genes had differential expression in the same direction in the same tissue type in at least 3 separate studies. Increased expression was reported in miR-106b-5p, miR-155-5p and miR-146a-5p in blood, post-mortem brain, and across several tissue types, respectively. Decreased expression was reported in miR-328-3p in bloods samples. Seven studies examined differential expression from other classes of ncRNA, including piRNA, snRNA, snoRNA and Y RNA. No individual ncRNA genes were reported in more than one study. Six studies reported differentially expressed snoRNA genes in ASD. A meta-analysis was not possible because of inconsistent methodologies, disparate tissue types examined, and varying forms of data presented.

CONCLUSION

There is limited but promising evidence associating the expression of certain miRNA genes and ASD, although the studies are of variable methodological quality and the results are largely inconsistent. There is emerging evidence associating differential expression of snoRNA genes in ASD. It is not currently possible to say whether the reports of differential expression in ncRNA may relate to ASD aetiology, a response to shared environmental factors linked to ASD such as sleep and nutrition, other molecular functions, human diversity, or chance findings. To improve our understanding of any potential association, we recommend improved and standardised methodologies and reporting of raw data. Further high-quality research is required to shine a light on possible associations, which may yet yield important information.

Stabilizing autism: A Fleckian account of the rise of a neurodevelopmental spectrum disorder

Using the conceptual tools of philosopher of science Ludwik Fleck, I argue that the reframing of autism as a neurodevelopmental spectrum disorder is constrained by two governing 'styles of thought' of contemporary psychiatry. The first is the historically conditioned 'readiness for directed perception' of, and thinking in terms of, ontologically distinct diseases. The clinical gaze of mental health professionals, the bureaucratic needs of health administration, the clinical and scientific utility of disease categories, and the practices of autism-oriented advocacy groups all imply a bias toward thinking about autism and related disorders as ontologically distinct psychiatric and scientific entities. Second, within the 'neuromolecular style of thought', mental disorders are more and more located at the neurobiological levels of the brain. In autism research, one of the biggest challenges is the identification of autism's neurobiological singularity. However, at a moment when biological and categorical approaches toward autism face serious empirical difficulties, a balance is established that holds together these two styles of thought. With a need to account for some of the most persistent uncertainties and conflicts in autism research, namely ubiquitous heterogeneity and a failure to identify disease specific biomarkers, the reframing of autism as a neurodevelopmental spectrum disorder satisfies the scientific, institutional and socio-political needs for stability and homogenization.

Psychopharmacological prescriptions for people with autism spectrum disorder (ASD): a multinational study

RATIONALE

Previous studies on psychotropic drugs prescribing in autism spectrum disorder (ASD) were from the USA or the UK. However, these studies may not be generalizable to other countries. There is a need to understand the extent of psychopharmacological prescribing for ASD treatment at a multinational level to identify areas of prescribing which lack evidence.

METHODS

We used the IMS Prescribing Insights database to investigate psychotropic drugs prescribing patterns for ASD treatment in children and adults in 2010-2012. Data were obtained from Europe (France, Germany, Italy, Spain and UK), South America (Mexico and Brazil), North America (Canada and USA) and Asia (Japan).

RESULTS

North American countries have the highest prescription rates, followed by the European and South American countries. Prescribing rates were higher in children compared to adults in individual countries. The most commonly prescribed drug for ASD was risperidone in young people (except in UK and Japan). In the UK, methylphenidate (34 %) was the most commonly prescribed for young people and haloperidol (44.1 %) in Japan. In adults, the most commonly prescribed drug class was antipsychotics and particularly risperidone (thioridazine and ziprasidone were the most prescribed antipsychotics in Brazil and USA, respectively).

CONCLUSION

There is variation in medication prescription for people with ASD among countries, which may be attributable to diagnostic criteria, clinical guidelines or health care systems. However, there is a lack of evidence of efficacy and safety for many psychotropic drugs prescribed for people with ASD. Research is needed to bridge the evidence gaps in prescribing.

Autism in flux: a history of the concept from Leo Kanner to DSM-5

In this paper, I argue that a new relation between past and present - a supposed historical continuity in the meaning of autism - is created by the histories written by the discipline itself. In histories of autism written by 'practitioner-historians', a sense of scientific progress and an essentialist understanding of autism legitimize and reinforce current understandings and research directions in the field of autism. Conceptual discontinuities and earlier complexities and disputes concerning classifying and delineating autism are usually left out of the positivist narrative of autism. In an alternative history of the concept of autism, I demonstrate that there have been major shifts in the type of symptoms, signs and impairments that were - and are - thought to be essential and specific for autism.

Deconstructing the PDD clinical phenotype: internal validity of the DSM-IV

BACKGROUND

Empirical studies of the structure of autism symptoms have challenged the three-domain model of impairment currently characterizing pervasive developmental disorders (PDD). The objective of this study was to assess the internal validity of the DSM as a conceptual model for describing PDD, while paying particular attention to certain subject characteristics.

METHODS

Parents and teachers completed a DSM-IV-referenced rating scale for 3- to 12-year-old clinic referrals with a PDD (n = 730). Ratings were submitted to confirmatory factor analysis and different models were assessed for fit.

RESULTS

Measures of fit indicated that the three-factor solution based on the DSM was superior to other models. Most indices of fit were acceptable, but showed room for improvement. Fit indices varied according to the rater (parent or teacher), child's age (preschool versus school aged), PDD subtype (autism, Asperger's, pervasive developmental disorder not otherwise specified (PDDNOS)), and IQ.

CONCLUSIONS

More research needs to be done before discarding current classification systems. Subject characteristics, modality of assessment, and procedural variations in statistical analyses impact conclusions about the structure of PDD symptoms.

Comprehensive synthesis of early intensive behavioral interventions for young children with autism based on the UCLA young autism project model

A 3-part comprehensive synthesis of the early intensive behavioral intervention (EIBI) for young children with autism based on the University of California at Los Angeles Young Autism Project method (Lovaas in Journal of Consulting and Clinical Psychology, 55, 3-9, 1987) is presented. The three components of the synthesis were: (a) descriptive analyses, (b) effect size analyses, and (c) a meta-analysis. The findings suggest EIBI is an effective treatment, on average, for children with autism. The conditions under which this finding applies and the limitations and cautions that must be taken when interpreting the results are discussed within the contextual findings of the moderator analyses conducted in the meta-analysis.

Examining the validity of autism spectrum disorder subtypes

The classification of autism spectrum disorders (ASDs) is a topic of debate among clinicians and researchers with many questioning the validity of the distinction among subtypes. This manuscript examines the validity of three ASD subtypes (Autism, Asperger's, and PDDNOS) by reviewing 22 studies published between 1994 and 2006. We reviewed studies that examined differences between the subtypes in terms of clinical and demographic characteristics, neuropsychological profiles, comorbidity, and prognosis. Results largely did not support differences between autism and Asperger's disorder based on current diagnostic criteria. Overall, the most salient group differences were noted when samples were categorized on IQ. Drawing definitive conclusions is difficult due to the inconsistent application of diagnostic criteria and circularity in methods.

Social skills and problem behaviours in school aged children with high-functioning autism and Asperger's Disorder

The social skills and problem behaviours of children with high-functioning autism and Asperger's Disorder were compared using parent and teacher reports on the Social Skills Rating System. The participants were 20 children with high-functioning autism, 19 children with Asperger's Disorder, and 17 typically developing children, matched on chronological and overall mental age. The children with autism and Asperger's Disorder were not differentiated on any social skill or problem behaviour based either on teacher or parent report. However, both clinical groups demonstrated significant social skill deficits and problem behaviours relative to the typically developing children, and the original standardization sample. The findings were compatible with the view that autism and Asperger's Disorder belong on a single spectrum of disorder.

Interacting and paradoxical forces in neuroscience and society

Discoveries in the field of neuroscience are a natural source of discourse among scientists and have long been disseminated to the public. Historically, as news of findings has travelled between communities, it has elicited both expected and unusual reactions. What scientific landmarks promote discourse within the professional community? Do the same findings achieve a place in the public eye? How does the media choose what is newsworthy, and why does the public react the way it does? Drawing on examples of past challenges at the crossroads of neuroscience and society and on a case study of trends in one neurogenetic disease, autism, we explore the dialectical forces interacting in scientific and public discourse.

Parental identification of early behavioural abnormalities in children with autistic disorder

The aim of the study was to identify early behavioural abnormalities in children later diagnosed with autistic disorder. Accurate identification of such deficits has implications for early diagnosis, intervention and prognosis. The parents of 153 children with autistic disorder completed a questionnaire asking them to describe early childhood behaviours of concern and to recall the age of onset. Core deficit-linked behaviours were then identified and the ontogeny of their development was noted. Behaviour categories were: (1) gross motor difficulties, (2) social awareness and play deficits, (3) language and communication difficulties, and (4) unusual preoccupations. The findings supported the notion that the nature and prevalence of these deficits depend on age. Consistent with past research, there was a significant interval between parents first noticing abnormalities and the making of a definitive diagnosis. The implications for this delay are discussed.

The CAST (Childhood Asperger Syndrome Test): preliminary development of a UK screen for mainstream primary-school-age children

The article describes a pilot and follow-up study of the preliminary development of a new tool to screen for Asperger syndrome (AS) and related social and communication conditions (the Childhood Asperger Syndrome Test, CAST) in children aged 4-11 years, in a non-clinical setting. In the pilot study, parents of 13 children with AS and of 37 typically developing children completed the CAST. There were significant differences between the AS and typical sample means. The pilot was used to establish preliminary cut-off scores for the CAST. In the main study, parents of 1150 primary-school-age children were sent the CAST, and 174 took part in the full data analysis. Results suggest that compared with other tools currently available, the CAST may be useful for identifying children at risk for AS and related conditions, in a mainstream non-clinical sample. Further research is ongoing.

Higher-functioning pervasive developmental disorders: rates and patterns of psychotropic drug use

OBJECTIVE

To explore the frequency, characteristics, and associated target symptoms of psychotropic drug use among subjects with higher-functioning pervasive developmental disorders (HFPDDs).

METHOD

A total of 109 children, adolescents, and adults (mean age = 13.9 years, SD = 6.9) consecutively seeking enrollment into the Yale Child Study Center's Project on Social Learning Disabilities were included in the study. Individuals in whom Asperger's disorder, autism, or pervasive developmental disorder-not otherwise specified had been previously diagnosed and who had a documented Full Scale IQ > or = 70 completed surveys on demographic, clinical, and medication history information. To naturalistically evaluate medication use patterns in this population, each drug class was analyzed with respect to demographic and clinical variables.

RESULTS

In all, 55% of subjects were taking psychotropics, with 29.3% taking 2 or more medications simultaneously. Antidepressants were the most commonly used agents (32.1%), followed by stimulants (20.2%) and neuroleptics (16.5%). The clinical presentation of subjects taking psychotropic agents was heterogeneous, and most consistently included anxiety-related target symptoms (in 65% of medicated individuals).

CONCLUSIONS

Psychotropic medication use appears to be common among subjects with HFPDDs, yet not generally based on the results of empirical research. Clinical heterogeneity among treated subjects suggests that psychiatric comorbidity may be overlooked in this population.