We searched the literature in 3 English databases (PubMed, Web of Science, and PsychInfo) and 2 Chinese databases (CNKI and Wanfang). The search items were (caregivers* OR caretakers* OR parents* OR psychiatrist* OR specialists*) AND (autism spectrum disorder OR ASD* OR autism* OR autistic) AND (genetic testing OR genetic assessment OR genetic risk assessment) AND (knowledge* OR awareness* OR perception* OR attitudes* OR experiences* OR utilization* OR utility* OR interest*). The final search was done on October 7, 2022, and searched literature was exported to Endnote X9.

Peer-reviewed articles that met all the following criteria were included in our research: (1) The targeted disease was ASD; (2) participants were either caregivers of children with ASD, adolescent and/or adult ASD patients, or health providers who provided medical services for them; and (3) the article focused on evaluating the knowledge, experiences, or attitudes about ASD clinical genetic testing. Articles were excluded if: (1) Participants other than the target population described above were included; (2) none of the three topics of interest was covered; (3) the study focused on prenatal genetic testing; (4) the article was not written in English or Chinese; (5) the study was a review; or (6) full-text was unavailable.

We first screened the searched papers by reading titles and abstracts. Then, full texts of the remaining studies were read and those that met the eligibility criteria were included for further study. These two steps were carried out by two independent reviewers. When there was non-conformity, a discussion was organized, and a senior reviewer was invited if necessary. The whole process of selection was displayed in the PRISMA flowchart (Figure 1)[37].

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Figure 1  PRISMA flowchart.

Relevant information of included papers was extracted into a charting form, including: (1) Characteristics of the study (author affiliation, country, year of publication, time period(s) of the study, study setting, sample size, sampling method, survey methods, and tools); (2) characteristics of participants (age of child at diagnosis and at survey time, financial insurance of child, relationship with ASD patients, age, gender, marital status, educational level, annual income, current employment status, number of children, number of children with ASD, and family history of ASD); and (3) main findings of the study (knowledge, experience, and attitudes concerning ASD genetic testing). The details were displayed in supplementary materials. After reading all 30 included articles and discussing them, a coding instruction was summarized by two reviewers. The data were then extracted by one reviewer and checked by another reviewer.

The original search yielded 483 records. After removing duplications and screening abstracts, 78 remained for full-text screening, after which, 30 records were included. Reasons for exclusion were a. inclusion of subjects other than the target population, for example, caregivers of patients with developmental disorders other than ASD, such as intellectual disability, developmental disorder (n = 16), general population (n = 16); b. not covering any of the three topics of our interest (n = 5). The process of article selection is displayed in Figure 1.

Among the final included 30 studies, 20 (66.7%) investigated knowledge, 17 (56.7%) investigated experience, and 22 (73.3%) investigated attitudes toward ASD genetic testing. They were published between 2012 and 2022, and conducted in 9 countries, with 19 (63.3%) in United States. More than half (n = 17, 56.7%) utilized convenience sampling. Other sampling methods included purposive sampling (n = 6, 20.0%), random sampling (n = 3, 10.0%), and snowballing sampling (n = 3, 10.0%). Investigating methods included online surveys (n = 16, 53.3%), face-to-face interviews (n = 9, 30.0%), and telephone calls (n = 7, 23.3%). The most frequently used instrument was a questionnaire with open-ended questions (n = 14, 46.7%). Some instruments included both close-ended and open-ended questions (n = 7, 23.3%), or only close-ended questionnaires (n = 7, 23.3%). More details can be found in Table 1. A standard questionnaire which was defined as a questionnaire with focused themes and standard evaluating methods and could be utilized by other researchers with a similar research purpose was used in two studies—Perceptions of ASD Genetic Testing Survey developed by Zhao et al[38] and The Centers for Autism and Related Disabilities developed by Cuccaro et al[39].

The majority of the studies (n = 29, 96.7%) investigated parents of children with ASD, including 23 (75.9%) that only covered parents, 4 (13.8%) that also covered other caregivers[27-29,31], one also included health providers[32], and 1 (3.4%) that included adolescent and adult patients[40]. Only one study investigated CAP alone[41]. The sample size of the 30 included studies ranging from 20 to 1444. Of 19 studies that provided gender information, 60%[35] to 95%[42] of the participants were female. Of 13 studies that reported the mean age of parents, these ranged from 37.4[36] to 46.7[43]. Of 8 studies that reported the marital status of parents, 81.3%[44] to 92.3%[45] were married or living as married. Of 8 studies that investigated current employment status, 51%-71.1% of caregivers were employed. Of 16 studies that provided information about the educational level of caregivers, 21.0%-69.4% had a college or higher degree. The lowest educational level of parents was reported in 2 studies that only involved parents of children with ASD who had taken CMA testing[46,47].

Age information of children with ASD was provided in some studies, including 7 (24.1%) that reported mean current age ranging from 5.2 to 16.5 years old[26,43] and 5 (16.7%) that reported mean age at diagnosis ranging from 3.0[29] to 4.7[48] years old. Among 7 studies that reported the number of children with ASD, most families (17.8%-93.7%) had only one child with ASD, while 5.9%-17.9% of families had two or more children diagnosed with ASD. Of 7 studies that addressed family history, 10.5%-34.6% of participants had a positive family history of ASD.

Specific questions related to the three topics of interest were (1) Knowledge: perceived cause(s) of ASD, knowledge about genetics and genetic testing, pathways to acquire such knowledge, and information needs prior to genetic testing; (2) Experience: experience of being referred to genetic testing and using genetic testing; and (3) Attitudes: why participants supported genetic testing and their concerns about genetic testing; for participants who have not done genetic testing, their intention to pursue genetic testing in the future; for participants who had done genetic testing, their satisfaction with ASD genetic testing and willingness to recommend genetic testing to others (Table 2).

Knowledge of genetics and ASD clinical genetic testing among parents and other caregivers: In total, there were 7 studies that surveyed the perceived cause(s) of ASD of the parents and other caregivers. These studies found that 51.0%-100% of the them thought ASD was partly or fully explained by genetic factors, and 11.9%-12.0% thought ASD was entirely explained by genetic factors. Parents who believed that their child’s ASD was permanent tended to attribute ASD to genetic factors[16]. One study reported parents’ understanding of genetics: parents stated that they were familiar with and knew the meaning of DNA (94%), genes (92%), chromosomes (86%), genetic testing (87%), and CMA (21%)[39].

In addition, there were 14 studies that investigated caregivers’ knowledge of genetic testing for ASD. Of seven studies that asked them whether they were aware of ASD genetic testing before the study, 17.0% to 78.1% answered yes[29,49-54]. However, one study reported that 95% of the participants said they did not know what genetic tests can test[26]. Furthermore, in one study of participants without genetic testing experience conducted in Sweden in 2020, only 16.2% of parents and 19.6% of autistic adolescents and adults believed that genetic testing for ASD was available[40]. There were three studies from the same team using the same seven-item questionnaire about knowledge of ASD genetic testing. In this questionnaire, wrong and correct answers were scored 0 and 1, with a total score ranging from 0 to 7. The three studies were all performed among parents with children with ASD from United States in 2019. The mean score for those studies were 2.4 ± 1.2 (n = 411), 2.5 ± 1.2 (n = 552), and 2.5 ± 1.2 (n = 443), respectively[18,24,26]. Caregivers’ knowledge of ASD genetic testing was positively associated with their educational level, the number of children with ASD, and socioeconomic status, and negatively related to the severity of the child’s ASD diagnosis[52,54,55]. Furthermore, caregivers who had visited a genetic service and who had received information from physicians rather than other sources also had a higher level of knowledge[55,56].

In 4 studies that reported the pathways through which the parents had acquired knowledge about ASD genetic testing, 18.3%-57.7% of the participants received related information from physicians[49,50,54,55]. Other main resources include the internet or mass media (23.9%-45.7%)[50,54,55], ASD organization or support groups (12.0%-42.9%)[50,54,55], and other parents of children with ASD (17.0%-36.4%)[50,54,55]. Two studies reported what information parents wanted to know to improve their knowledge about genetic testing. This information included: accuracy of genetic testing (38% and 88.4%), cost (60.0% and 85.9%), benefits of genetic testing (48.0% and 83.8%), testing procedure (29.0% and 77.8%), eligibility to undergo genetic testing (62.4%), potential harms caused by genetic testing (29.0% and 56.1%), previous use and experience among individuals affected by ASD (50.8%), and confidentiality issues (12.0% and 48.0%)[53,55].

Experiences of ASD clinical genetic testing: Parents and other caregivers: Three (10.0%) of the 30 studies only included parents of children with ASD who had undergone CMA testing, and one only included parents who had been offered any genetic testing for their child with ASD. Among the remaining studies, 6 reported that 9.1% to 72.7% of caregivers and 2.8% of autistic adolescents/adults[40] had been referred to genetic testing, and 13 (43.3%) studies reported rates of using any type of genetic testing ranging from 17.4% in United States[29] to 61.7% in France[28]. Regarding specific types of genetic testing, fragile X testing was most widely used by parents, with utilization rates ranging from 4.4% to 39.2%[36,39,49,56]. The utilization rates of CMA and karyotype tests were 7.4%-13.1%[49,56], and 0.7%-37.6%[36,49,56], respectively. Only one study in Jordan reported that the usage rate of WES was 3.3%[36]. The associated factors of caregivers’ usage of genetic testing were reported in 4 studies. Those who had a higher awareness level of genetic testing[49], who received related information from healthcare providers rather than other sources[31,49], who had visited geneticists[31,56], and those with higher household income[36] were more likely to conduct genetic testing for their child.

Health providers: Only one study was of CAP and was performed in United States in 2021. It showed that 54.9% of respondents had ordered ASD genetic testing for their patients in the prior 12 mo. Psychiatrists who accepted a higher percentage of ASD cases, who had more knowledge about genetic testing and higher perceived utility of ASD genetic testing, and who were at a University medical center were more likely to request genetic testing for their patients with ASD; participants with more years of working experience tended not to order genetic testing for their patients with ASD[41].

Attitudes towards ASD clinical genetic testing: Parents and other caregivers: There were 15 surveys among caregivers which reported participants’ reasons for supporting genetic testing. Reasons could be categorized into three groups: (1) Benefits for the child, including getting better intervention (n = 13), finding out the cause(s) of ASD (n = 11), getting a definitive diagnosis (n = 8), getting a better understanding of their condition (n = 6), and additional resources (n = 5); (2) Benefits for family and parents, including helping with family planning (n = 8), and future reproductive decisions (n = 5), identifying risk of associated children (n = 2), and reducing stigma (n = 1); and (3) Benefits for other people, including promoting scientific research (n = 6), and providing an indication for other children with ASD (n = 1) (Figure 2A).

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Figure 2 The support rates of potential benefits and concerns of autism spectrum disorder genetic testing. A. Potential benefits of autism spectrum disorder (ASD) genetic testing; B. Potential concerns about ASD genetic testing. Each dot represents a study and the total number of studies that report the corresponding benefit/concern is displayed on the right side of the figure. Benefits/concerns were sorted by the median of the reported support rate of the participants. ^aindicates that there are studies that only report a qualitative description.

Of caregivers who had taken their child for genetic testing, more than half held positive attitudes toward their experience of genetic testing, reporting that genetic testing had been helpful for their child and their family[29,46,49]. Getting additional resources (81.8%), getting a definitive diagnosis (81.8%), contributing to scientific knowledge (61.8%), identifying associated medical risks (25.0%), playing a role in future reproductive decisions (19.1%), helping with treatment planning (12.5%, 16.2%, 90.9%), gaining a better understanding of the child (10.3%), finding a cause of ASD (10.3%, 12.5%), and helping with family planning were reasons why they thought genetic testing was useful[29,31,46,49]. Two studies compared perceived benefits between caregivers, one who had taken their children for genetic testing and the other who never had. The first showed that the post-test group had more positive attitudes toward ASD genetic testing[31], the second reported less positive attitudes[27].

There were 15 studies that reported caregivers’ concerns about genetic testing. They can be divided into four areas: (1) High cost (n = 6); (2) useless results: Would not provide any useful information (n = 9), would not help with treatments (n = 5), and would not make changes to daily life (n = 4); (3) negative influences: Would cause family conflicts (n = 4), would cause stress/risk/pain to children (n = 3), cause parental concern (n = 2), would do more harm than good (n = 2), and contradict their religious or cultural beliefs (n = 1); would cause discrimination when buying financial insurance (n = 3) and public discrimination (n = 1); and (4) other: The test had poor validity (n = 1) (Figure 2B). Four studies reported concerns of participants who had taken their child to genetic testing: lack of detailed information and did not help with further treatment and financial costs were the main reasons for dissatisfaction[26,40,44,49]. Parents’ attitudes towards genetic testing were positively related to their perceived severity of ASD[57] and negatively related to their perceived barriers in conducting genetic testing[57], and parents’ age and educational level[52].

There were 8 (26.7%) studies which reported that 46.7%[54] to 95%[56] of caregivers without previous genetic testing experience intended to pursue genetic testing in the future, and 2 studies showed that 50.5% and 59.6% parents who have purchased genetic testing services for their children would recommend genetic testing to other parents. It is reported that parents’ willingness to pursue genetic testing for their children with ASD was positively associated with their attitudes towards genetic testing, their perception of other people’s opinions, and their self-efficacy in pursuing genetic testing[57].

Health provides: Only one survey among CAP reported why they order genetic testing for their patients. The main reason is to diagnose ASD and reported by 59.9% of those who had ordered a genetic testing in the prior 12 mo[41].

Firstly, more actions should be taken to improve the knowledge level of genetic testing among caregivers of patients with ASD. Health education through health providers, like physicians and psychiatrists, is the most effective way. Secondly, improving the knowledge of genetic testing among health providers is necessary for better utilization of genetic testing in ASD practice. Thirdly, caregivers of patients with ASD and patients themselves generally hold a positive attitude toward genetic testing. More comprehensive knowledge is needed to avoid potential misunderstandings.

The popularity of genetic testing for patients with autism spectrum disorder (ASD) varies dramatically across countries. It is highly dependent on the knowledge, experiences, and attitudes toward genetic testing among caregivers of children with ASD, adolescent and adult ASD patients, and health providers. As a result, many related studies have been conducted worldwide but no systematic review has been done.

Getting a better knowledge of factors that are associated with the usage rate of genetic testing for patients with ASD has the potential to maximize the benefits of the test for patients.

To systematically review research on knowledge, experiences, and attitudes towards genetic testing among caregivers of children with ASD, adolescent and adult ASD patients, and health providers.

We conducted a systematic review by searching the related literature without area and time limitations in both English language and Chinese language databases.

In 30 studies conducted in 9 countries,17.0% to 78.1% of caregivers/patients were aware of ASD genetic testing. However, they lacked a full understanding of it. Between 9.1% and 72.7% of caregivers in different studies were referred for genetic testing, and between 17.4% and 61.7% actually obtained genetic testing. Among caregivers, 46.7% to 95.0% without previous genetic testing experience intended to obtain it in the future, and 50.5% to 59.6% of parents who previously obtained genetic testing would recommend it to other parents. In a single study of child and adolescent psychiatrists, 54.9% of respondents had ordered ASD genetic testing for their patients in the prior 12 mo.

The usage rate varied widely in different studies. It is mainly affected by the knowledge level of related parties. However, the review showed that although most caregivers are willing to learn about and use genetic testing, their current knowledge is limited.

Firstly, more actions should be taken to improve the knowledge level of genetic testing among caregivers of patients with ASD. Health education through health providers, like physicians and psychiatrists, is the most effective way. Secondly, improving the knowledge of genetic testing among health providers is necessary for better utilization of genetic testing in ASD practice. Thirdly, caregivers of patients with ASD and patients themselves generally hold a positive attitude toward genetic testing. More comprehensive knowledge is needed to avoid potential misunderstandings.