Background
Williams syndrome (WS) is a neurogenetic disorder that occurs in about 1 in every 8,000 live births. WS is caused by the contiguous deletion of 26–28 genes on chromosome 7q11.23. Individuals with WS exhibit compelling psychological phenotypes, including cognitive strengths and weaknesses, and display unique patterns of social behavior [
1] An increased appetitive drive toward social interaction is one of the most significant social phenotypes of WS [
2]. People with WS may frequently approach others, including strangers, with a disregard for potentially negative consequences. In the process of raising children with WS, many parents and caregivers are challenged by the task of teaching their children to behave in socially acceptable ways.
“Adaptive behavior” refers to the functioning of an individual in his or her social environment. Evaluation of adaptive behavior includes several aspects, such as communication, socialization, daily living, and motor skills. Using some form of the Vineland Adaptive Behavior Scales (VABS) [
3], children with WS have been found to have strong socialization (especially interpersonal skills related to initiating social interaction) and communication skills, and poor daily living and motor skills, relative to their overall level of adaptive functioning. Some researchers have reported that the adaptive behaviors of people with WS are poor compared with those of the normal population [
4‐
6].
Unlike Down syndrome, which is the most common cause of inherited intellectual disability, WS is a relatively rare disease that is generally diagnosed only by pediatricians in big cities. In China, individuals with WS are considered to have a general intellectual disability. Although they face a variety of life-long challenges, these individuals may marry and have children, although their offspring may also have genetic abnormalities.
The goal of this study was to explore social ability and behavioral development in children with WS in China. We chose a systematic approach in which children with WS were compared with normal children who were matched for both mental age and chronological age. To the best of our knowledge, no studies have reported on social ability and behavioral development in Chinese children with WS. The aim of this study was to determine whether an etiology-specific profile exists for social adaptation in Chinese people with WS. To this end, we used the Infants-Junior Middle School Students’ Social-Life Abilities Scale [
7].
Discussion
The purpose of this study was to obtain more information about the adaptive behavior of children with WS in China. As no thoroughly validated instruments for measuring cognitive development are available in Chinese, we used the PPVT to measure intelligence level.
In Western countries, several studies using a variety of standardized measures (e.g., Wechsler Intelligence Scales, Kaufman Brief Intelligence Test–K-BIT, Stanford Intelligence Scales and Differential Ability Scales–DAS) have reported a high incidence of intellectual disability in people with WS, ranging from mild to moderate [
10]. Previous studies have found that individuals with WS score between 55 and 69 on intelligence assessments, while the standard global score for people with intellectual disabilities is between 40 and 90 [
11‐
14]. These scores appear to remain stable during adulthood [
12,
13,
15].
Many different strategies can be effective in treating people with disabilities in developed countries. Children with WS in developed countries may have greater access to appropriate interventions, and their parents may be more educated about treatment options. However, most of the diagnoses of children with WS in China have been made recently compared with developed countries. The highest IQ score that we found in our sample population was 61, and only 3 of the children with WS that we studied had received special interventions. The low level of cognition and social competence that we observed suggests that Chinese families with children with WS lack appropriate professional help, which is necessary to promote the ability of their children early on in development.
Family structure plays an important role in the cognitive and social development of children. Since the implementation of the family planning policy in China, family characteristics have undergone great changes. Many couples who are permitted to have a second child choose to have only one child, although those who have disabled children may often choose to have two children [
16]. The nuclear family with one child has become the norm in Chinese society. When a family has a new baby or toddler, or has a handicapped child, the grandparents are usually invited to live together with the young family, for economic reasons or as a matter of custom. As the child grows up, the grandparents generally move out to live by themselves, often while the child is relatively young. Grandparents of children with WS often continue to live with the family to provide additional support. Therefore, the nuclear family structure with one child is the standard social living environment for healthy children the same age as those in the CA group in our study, although this is not the case for children like those in our WS or the MA groups. A handicapped child is usually treated as the most important member of the family. However, the practice of spoiling disabled children may slow the development of their abilities, because these children may have fewer chances to practice skills related to independence.
In addition to family structure, the educational level of the caregivers (mainly parents) plays an important role in the development of social adaptation [
17]. Compared with typically-developing children, we found the educational level of parents with children with WS to be significantly lower. In more prosperous regions of China, prenatal screening has become a popular option for well-off parents. To some degree, parents with a lower educational level are less likely to participate in routine examinations during pregnancy, increasing their chance of missing prenatal diagnoses of many genetic diseases. After the birth of a child with WS, well-educated parents may provide a better environment for the growth and development of their disabled child and may participate in early intervention programs more readily. Early intervention can help many children with WS to develop their full cognitive and social potential and live productive lives well into adulthood.
In our study, children in the CA group received higher scores than those in the WS group for all dimensions of adaptive behavior. This is consistent with the opinion that the development of cognition is associated with the development of adaptive behavior and improvement in quality of life [
18,
19]. The development of adaptive behavior is influenced by language, motor development and executive function. A focus on cognitive skills appears to improve individual potential and social adaptation, while traditional types of education and training are considered to be less helpful for children with developmental disabilities.
We found no differences between children with WS and those in the MA groups in terms of locomotion, work skill, socialization, and self-management, while children with WS obtained higher scores of self-dependence and communication. This result is consistent with the notion that intellectual disability does not inhibit learning and adaptation. Greer examined the performance of children with WS aged 4–18 years and found that standard scores on the Socialization and Communication scales were significantly higher than standard scores on the Daily Living Skills or Motor Skills scales [
6]. On another parent-interview measure, the Scales of Independent Behavior - Revised, children with WS performed significantly better on the Social Interaction and Communication Skills scale compared with the remaining scales [
20]. In this study, we found that, with the exception of the communication domain, children with WS had higher levels of self-dependence than children in the MA group. This result has not been reported previously. Generally, the mental age of the children with WS in our study was about 3 years old. Items related to self-dependence for this age group include finishing a meal independently and getting dressed (or undressed), which are not necessarily skills that are taught to Chinese children at this age. Basic living skills in people with WS significantly improve after many years of training, although they will generally be much lower than those of people in a CA-matched group.
Menghini found that individuals with WS had difficulties with movement, visuospatial construction, and executive functions, which contribute to the difficulty level of daily skills, such as dressing, cleaning, or playing games [
21]. Indeed, locomotion, work skills, and self-management are dependent on motor skills. Children with WS may develop verbal and auditory rote memory abilities, and may develop strong personality characteristics that aid in social adaption, such that they are comparable to the children in the MA-matched group in our study. It is possible that overprotection from caregivers reduces the opportunities for children with WS to develop their skills; especially as family members learn to communicate with and satisfy the child. This may prevent the development of social adaption strategies.
Competing interests
The authors received financial support from Zhejiang Province innovation team for early screening and intervention of birth defects (Grant No. 2010R50045). The authors declare no conflict of interest in relation to academic, religious or political aspects.
Authors’ contributions
CJ and ZZ designed the study and wrote the manuscript. WC performed the statistical analysis. Dan Yao and ML supervised the analysis and interpretation of results and contributed to the revision of the manuscript. All of the authors agreed on the final version of the manuscript.