Autism spectrum disorder in Chinese populations: a brief review

Public concerns and attitudes towards autism on Chinese social media based on K-means algorithm

To investigate the hot topics and attitudes of autism in the larger community. In this study, we analyzed and summarized experimental texts from the social media platform Zhihu using the TF-IDF algorithm and K-means clustering approach. Based on the analysis of the 1,740,826-word experimental text, we found that the popularity of autism has steadily risen over recent years. Sufferers and their parents primarily discuss autism. The K-means clustering algorithm revealed that the most popular topics are divided into four categories: self-experience of individuals with autism, external views of individuals with autism, caring and stressful behaviors of caregivers, and information about autism. This study concluded that people with autism face more incredible negative emotions, external cognitive evaluations of the autistic group reflect stereotypes, the caregiver's family suffers high financial and psychological stress, and disorders caused by disease in autistic individuals.

Behavioural deficits of autism spectrum disorder and associations with different gene clusters: a study with the whole-genome transmission disequilibrium test

BACKGROUND

Autism spectrum disorder (ASD) is a diverse neurodevelopmental disease primarily distinguished by limited and stereotyped activities as well as impaired social interaction. Due to the high heritability of ASD, research on the disorder has emphasised on identifying the underlying genetic and epigenetic aetiology. Many ASD loci have been identified by genome-wide association studies (GWASs). However, GWASs are more susceptible to bias due to population stratification. Moreover, GWASs barely reflect the genetic aetiology of subtypes of behavioural deficits.

METHODS

We applied whole-genome transmission disequilibrium test (TDT) to reveal the gene sets that are significantly associated with the four behavioural subtypes of restricted repetitive behaviours in 334 ASD trios. We further mapped the clustered genes to pathways and enriched the SFARI genes in these pathways.

RESULTS

Four unique gene clusters (181 genes in total) that are related to four different behavioural subtypes in ASD were identified. 23 SFARI genes were enriched in these four clusters. Through pathway analysis, nine non-SFARI genes (CNDP1, ETNK1, ITPKB, KCNQ5, PDE4D, PDGFRA, PPARGC1A, ULK2, SYNJ2) were found to be linked to the SFARI genes, which may contribute to the development of ASD. Furthermore, we found that the mTOR pathway enriched with the CNDP1, PDE4D, ULK2 genes is associated with neurodevelopment.

CONCLUSIONS

Whole-genome TDT test is a unique tool in clustering genes related to ASD subtypes of behavioural deficits. Several new candidate genes for ASD are revealed by pathway analysis of the clustered genes. These findings are useful for understanding the underlying mechanism of ASD.

DIP2C polymorphisms are implicated in susceptibility and clinical phenotypes of autism spectrum disorder

BACKGROUND

Disco-interacting protein 2 C (DIP2C) has recently been reported as a new susceptibility gene for autism spectrum disorder (ASD) in a genome-wide association study.

METHODS

We evaluated associations between single nucleotide polymorphisms (SNPs) of DIP2C and ASD susceptibility in a case-control study (715 ASD cases and 728 controls) from Chinese Han.

RESULTS

We identified a significant association between SNPs (rs3740304, rs2288681, rs7088729, rs4242757, rs10795060, and rs10904083) and ASD susceptibility. Of note, rs3740304, rs2288681, and rs7088729 are positively associated with ASD under inheritance models; moreover, haplotypes with any two marker SNPs (rs3740304 [G], rs2288681 [C], rs7088729 [T], rs4242757 [C], rs10795060 [G], and rs10904083 [A]) are also significantly associated with ASD. Additionally, rs10795060 and rs10904083 are associated with "visual reaction" phenotypes of ASD.

CONCLUSIONS

DIP2C polymorphisms sort out the susceptibility and clinical phenotypes of autism spectrum disorder.

Cultural Adaptation and Validation of Mullen Scales of Early Learning in Taiwanese children with Autism Spectrum Disorder, Global Developmental Delay, and Typically Developing Children

BACKGROUND

The Mullen Scales of Early Learning (MSEL) is a standardized comprehensive developmental assessment tool for children aged 0-68 months. However, few Asia-based studies have explored cultural and linguistic adaptations of the MSEL or investigated its psychometric properties in populations with autism spectrum disorder (ASD).

AIMS

This study evaluated the reliability and validity of the MSEL-Taiwan version (MSEL-T) for Taiwanese children with ASD, global developmental delay (GDD), and typical development (TD).

METHODS AND PROCEDURES

The MSEL items were translated and modified according to the language and culture in Taiwan. In total, 191 children (ASD, 69; GDD, 36; and TD, 86) aged 19-68 months were assessed using the MSEL-T and Peabody Developmental Motor Scales 2 (PDMS-2) at enrollment, followed by the assessments of Vineland Adaptive Behavior Scale-Chinese version (VABS-C) at the age of 36 months or later.

OUTCOMES AND RESULTS

All subscales were verified to have good interrater reliability and internal consistency, and subscale scores indicated moderate to high correlations with PDMS-2 and VABS-C scores. Significant differences in MSEL-T scores were observed between same-aged pairs of children with TD and GDD and between pairs of children with TD and ASD.

CONCLUSIONS AND IMPLICATIONS

The findings provide evidence of validity and reliability of the MSEL-T. And it is suggested that the culturally and linguistically adapted MSEL-T is a good tool for the clinical assessment of children with and without ASD.

Mutation screening of the UBE3A gene in Chinese Han population with autism

BACKGROUND

15q11-13 region is one of the most complex chromosomal regions in the human genome. UBE3A is an important candidate gene of autism spectrum disorder (ASD), which located at the 15q11-13 region and encodes ubiquitin-protein ligase E3A. Previous studies about UBE3A gene and ASD have shown inconsistent results and few studies were performed in Chinese population. This study aimed to detect the genetic mutations of UBE3A gene in Chinese Han population with ASD and analyze genetic association between these variants and ASD.

METHODS

The samples consisted of 192 patients with autism according to the DSM-IV diagnostic criteria and 192 healthy controls. We searched for mutations at coding sequence (CDS) regions and their adjacent non-coding regions of UBE3A gene using the high resolution melting (HRM) and Sanger sequencing methods. We further increased sample size to validate the detected variants using HRM and conducted association analysis between case and control groups.

RESULTS

A known single nucleotide polymorphism (T > C, rs150331504) located at the CDS4 and a known 5 bp insertion/deletion variation (AACTC+/-, rs71127053) located at the intron region of the upstream 288 bp of the CDS2 of UBE3A gene were detected using Sanger sequencing method. The ASD samples of case group were 391 for rs71127053, 384 for rs150331504 and 384 healthy controls, which were used to make an association analysis. The results of association analysis suggested that there were no significant difference about the allele and genotype frequencies of rs71127053 and rs150331504 between case and control groups after extending the sample size. Besides, rs150331504 is a synonymous mutation and we compared the secondary structure and minimum free energy (MFE) of mRNA harboring the allele T or C of rs150331504 using RNAfold software. We found that the centroid secondary structure apparently differs along with the polymorphisms of rs150331504 T > C, the results suggested that this variant might change the secondary structure of mRNA of UBE3A gene. We did not detect mutations in other coding regions of UBE3A gene.

CONCLUSIONS

These findings showed that UBE3A gene might not be a major disease gene in Chinese ASD cases.

Prevalence of Autism Spectrum Disorder in China: A Nationwide Multi-center Population-based Study Among Children Aged 6 to 12 Years

This study aimed to obtain the first national estimate of the prevalence of autism spectrum disorder (ASD) in Chinese children. We targeted the population of 6 to 12-year-old children for this prevalence study by multistage convenient cluster sampling. The Modified Chinese Autism Spectrum Rating Scale was used for the screening process. Of the target population of 142,086 children, 88.5% (n = 125,806) participated in the study. A total of 363 children were confirmed as having ASD. The observed ASD prevalence rate was 0.29% (95% CI: 0.26%-0.32%) for the overall population. After adjustment for response rates, the estimated number of ASD cases was 867 in the target population sample, thereby achieving an estimated prevalence of 0.70% (95% CI: 0.64%-0.74%). The prevalence was significantly higher in boys than in girls (0.95%; 95% CI: 0.87%-1.02% versus 0.30%; 95% CI: 0.26%-0.34%; P < 0.001). Of the 363 confirmed ASD cases, 43.3% were newly diagnosed, and most of those (90.4%) were attending regular schools, and 68.8% of the children with ASD had at least one neuropsychiatric comorbidity. Our findings provide reliable data on the estimated ASD prevalence and comorbidities in Chinese children.

Validation of the modified checklist for autism in toddlers, revised with follow-up in Taiwanese toddlers

BACKGROUND

The Modified Checklist for Autism in Toddlers, Revised with Follow-Up (M-CHAT-R/F) is a two-stage screening scale for determining the risk of autism spectrum disorder (ASD) in toddlers. However, the validity of the M-CHAT-R/F for Asian populations has not yet been established.

AIMS

This study investigated the psychometric properties of the M-CHAT-R/F, Taiwan version (M-CHAT-R/F-T), among low- and high-risk Taiwanese toddlers aged 16-30 months. The associations among M-CHAT-R/F-T scores, developmental performance at 24 and 30 months, and ASD diagnosis prediction at 36 months were examined.

METHODS AND PROCEDURES

A two-stage screening of the M-CHAT-R/F-T was applied to a study sample comprising 25 toddlers with ASD and 71 atypically developing (ATD) and 221 typically developing (TD) toddlers.

OUTCOMES AND RESULTS

The M-CHAT-R/F-T exhibited acceptable internal consistency and test-retest reliability. The M-CHAT-R/F-T scores were significantly correlated with several syndrome scores of the Child Behavior Checklist for Ages 1.5-5 and were significantly higher among toddlers with ASD than among ATD or TD toddlers. Furthermore, M-CHAT-R/F-T scores were negatively correlated with developmental scores in the Mullen Scales of Early Learning at 24 and 30 months. Moreover, the screening exhibited acceptable predictive validity (sensitivity = 0.86; specificity = 0.96) for ASD diagnosis at 36 months.

CONCLUSIONS AND IMPLICATIONS

The findings indicate that the M-CHAT-R/F-T is a valid and reliable tool for the developmental screening of low- and high-risk Taiwanese toddlers in community and clinical settings.

Dental utilization and expenditures by children and adolescents with autism spectrum disorders: A population-based cohort study

Objectives:

It is understood that children and adolescents with autism spectrum disorders (ASDs) have difficulty in receiving dental treatment. This study explores the differences in dental utilization and expenditure between two groups: children and adolescents with and without ASD. Different conditions that affect these results will be examined, including area of residence, category of treatment, and preferences concerning type of dental institution in Taiwan.

Materials and Methods:

The health service research database of the National Health Research Institutes, which features population-based, randomly selected samples collected from 2001 to 2010, was utilized in this study. In particular, we recruited samples from 2005 in accordance with the codes of the International Classification of Diseases, 9^th revision, Clinical Modification from 299.0 to 299.9. The population-based cohort study measured mean expenditures and mean numbers of medical visits with regard to different dental institution classifications, areas of residence, and categories of dental treatment for children (under 18 years old) with and without ASD.

Results:

The mean number of annual visits was 6.58 and 5.70 for children and adolescents with and without ASD, respectively, with mean annual visit expenditures of NT$2401.20 and NT$1817.99, respectively. A higher percentage of children (91.32%) and adolescents (72.66%) with ASD had experienced dental treatment than those without ASD. Children (93.23%) and adolescents (90.83%) without ASD visited dental clinics more often than those with ASD. The percentage of dental visits to academic medical centers in Eastern Taiwan was significantly lower for the ASD group than visits to other types of dental institutions. The use of restorative treatment was significantly higher among all samples, with periodontology having the lowest percentage.

Conclusions:

Children and adolescents with ASD had greater dental utilization, expenditures, and preferences for high-level dental institutions. The discrepancies in dental utilization indicate differences in the distribution of medical resources in different dental institution levels and residence areas in Taiwan.

Associations among maternal pre-pregnancy body mass index, gestational weight gain and risk of autism in the Han Chinese population

BACKGROUND

Autism is a neurodevelopmental disorder with an unclear etiology. Pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) have been suggested to play a role in the etiology of autism. The current study explores the associations among maternal pre-pregnancy BMI, GWG and the risk of autism in the Han Chinese population.

METHODS

Demographic information, a basic medical history and information regarding maternal pre-pregnancy and pregnancy conditions were collected from the parents of 705 Han Chinese children with autism and 2236 unrelated typically developing children. Binary logistic regressions were conducted to calculate the odds ratio (OR) for the relationship among pre-pregnancy BMI, GWG and the occurrence of autism. The interaction between pre-pregnancy BMI and GWG was analyzed by performing stratification analyses using a logistic model.

RESULTS

After adjusting for the children's gender, parental age and family annual income, excessive GWG was associated with autism risk in the entire sample (OR = 1.327, 95% CI: 1.021-1.725), whereas the relationship between maternal pre-pregnancy BMI and autism was not significant. According to the stratification analyses, excessive GWG increased the risk of autism in overweight/obese mothers (OR = 2.468, 95% CI: 1.102-5.526) but not in underweight or normal weight mothers.

CONCLUSIONS

The maternal pre-pregnancy BMI might not be independently associated with autism risk. However, excessive GWG might increase the autism risk of offspring of overweight and obese mothers.

Socioeconomic status and childhood autism: A population-based study in China

There is limited evidence on the association between socioeconomic status (SES) and autism in developing nations. The aim of this study was to examine this association among children aged 0-17 years in China. We obtained data from the Second National Sample Survey on Disability, and selected 616,940 children for analysis. Autism was ascertained according to the International Statistical Classification of Diseases, Tenth Revision. Multiple logistic regressions allowing for weights showed that children in middle-income and high-income families were less likely than their low-income peers to have autism, with an odds ratio of 0.60 (95%CI: 0.39, 0.93) and 0.44 (95%CI: 0.27, 0.72), respectively. Children in middle-education families had 63% (95%CI: 41%, 95%) odds of autism relative to their counterparts in low-education families. Stratified analyses found that all observed associations were only in male children, not in female children. In conclusion, children in families with socioeconomic disadvantage, in the form of lower family income and education, had greater risk of childhood autism.

High resolution analysis of rare copy number variants in patients with autism spectrum disorder from Taiwan

Rare genomic copy number variations (CNVs) (frequency <1%) contribute a part to the genetic underpinnings of autism spectrum disorders (ASD). The study aimed to understand the scope of rare CNV in Taiwanese patients with ASD. We conducted a genome-wide CNV screening of 335 ASD patients (299 males, 36 females) from Taiwan using Affymetrix Genome-Wide Human SNP Array 6.0 and compared the incidence of rare CNV with that of 1093 control subjects (525 males, 568 females). We found a significantly increased global burden of rare CNVs in the ASD group compared to the controls as a whole or when the rare CNVs were classified by the size and types of CNV. Further analysis confirmed the presence of several rare CNVs at regions strongly associated with ASD as reported in the literature in our sample. Additionally, we detected several new private pathogenic CNVs in our samples and five patients carrying two pathogenic CNVs. Our data indicate that rare genomic CNVs contribute a part to the genetic landscape of our ASD patients. These CNVs are highly heterogeneous, and the clinical interpretation of the pathogenic CNVs of ASD is not straightforward in consideration of the incomplete penetrance, varied expressivity, and individual genetic background.

Body fluid levels of neuroactive amino acids in autism spectrum disorders: a review of the literature

A review of studies on the body fluid levels of neuroactive amino acids, including glutamate, glutamine, taurine, gamma-aminobutyric acid (GABA), glycine, tryptophan, d-serine, and others, in autism spectrum disorders (ASD) is given. The results reported in the literature are generally inconclusive and contradictory, but there has been considerable variation among the previous studies in terms of factors such as age, gender, number of subjects, intelligence quotient, and psychoactive medication being taken. Future studies should include simultaneous analyses of a large number of amino acids [including d-serine and branched-chain amino acids (BCAAs)] and standardization of the factors mentioned above. It may also be appropriate to use saliva sampling to detect amino acids in ASD patients in the future—this is noninvasive testing that can be done easily more frequently than other sampling, thus providing more dynamic monitoring.

Perinatal and background risk factors for childhood autism in central China

Perinatal and background risk factors for autism were identified in a cohort of autistic children in Zhengzhou, China, to formulate preventative and treatment strategies for high-risk families. In this case-control study, children were screened for suspected autism using the Autism Behavior Checklist (ABC) and diagnosed according to DSM-IV and the Childhood Autism Rating Scale (CARS). We collected perinatal histories and clinical data of 286 confirmed autistic children treated at the Third Affiliated Hospital Children׳s Psychological Clinic of Zhengzhou University from 2011 to 2013. The control group consisted of 286 healthy children from area kindergartens. Maternal age>30 years, parental introversion as measured by the Eysenck Personality Questionnaire, low level of parental education, smoking, abortion threat, pregnancy complications, maternal illness during pregnancy, maternal mental health, family history of mental illness, neonatal jaundice, birth asphyxia, premature rupture of the fetal membrane, and gestational age<37 weeks were significantly higher in the autism group. These factors were significantly correlated with behavioral symptoms as measured by ABC scores (Kendall rank correlation). Birth asphyxia, neonatal jaundice, maternal age, parental introversion, family history of mental illness, abortion threat, premature delivery, and smoking were identified as independent risk factors by multivariate logistic regression.

Prevalence of autism spectrum disorders among children in China: a systematic review

BACKGROUND

There are no reliable estimates of the prevalences of autism and autism spectrum disorders (ASD) in China.

OBJECTIVE

Combine results across studies to estimate the prevalences of autism and ASD among Chinese children under the age of 18, and assess variations in the prevalences with respect to gender, ethnicity, and urban versus rural residence.

METHODS

Based on pre-defined inclusion and exclusion criteria, studies were identified by searching the following databases: Chinese National Knowledge Infrastructure, Chongqing VIP database for Chinese Technical Periodicals, WANFANG DATA, Chinese Biological Medical Literature Database, Pubmed, and Web of Science. Statistical analysis was conducted using R-2.15.2 software.

RESULTS

The 24 studies meeting inclusion criteria included 5 registry studies from Taiwan and Hong Kong (covering a total of 14570 369 children) and 19 community-based screening and diagnostic studies from mainland China (with a combined sample of 771 413 children). The annually reported prevalence of autism in the registry studies ranged from 1.8 to 424.6 per 10 000. A meta-analysis of 18 of the studies from mainland China (excluding a large nationwide study with the lowest prevalence of autism) with a range in rates from 2.8 to 30.4 per 10 000 generated an estimated pooled prevalence of autism of 12.8 per 10 000 (95%CI, 9.4 to 17.5). The pooled prevalence of ASD estimated from 5 of these studies (which had a range in rates from 7.3 to 75.3 per 10 000) was 24.5 per 10000 (95%CI, 10.4 to 57.4). The reported prevalence of autism varied substantially by gender, location of residence, date of publication, and source of the sample.

CONCLUSION

The huge difference between the rates for autism reported from registry systems in Hong Kong and Taiwan (a 200-fold difference) and the large differences in rates reported from community-based screening studies in mainland China (a 10- to 15-fold difference) highlight the urgent need for establishing standardized methods for estimating the prevalences of autism and ASD. Until these methodological improvements have been made, it will not be possible to develop evidence-based prevention and treatment strategies for the management of these uncommon but seriously disabling conditions.