Features of developmental functions and autistic profiles in children with Fragile X syndrome

Background: In this study, we investigated the developmental functions and autistic profiles in children with Fragile X syndrome (FXS). In addition, we established the relationships between developmental and autistic profiles in these children. Methods: The medical records of 12 children with FXS, aged 2 to 7 years, were collected. Fifteen children with autism, without FXS, who were age- and sex-matched were selected as the comparison group. All children underwent assessments of developmental functions according to the Chinese Child Development Inventory (CCDI), and autistic profiles according to the Childhood Autism Rating Scale (CARS). Differences in genders between the two groups were determined with the Fisher's exact test. Differences in developmental functions (CCDI) and autistic profiles (CARS) between the two groups were compared using Mann-Whitney U test and Bonferroni adjustment. The Spearman's rho correlation was used to determine the relationship of developmental functions and autistic profiles. Results: All developmental functions in children with FXS were better than those with autism except for gross motor, fine motor and expressive language functions. Children with FXS had the worst expressive language function (56% Development Quotient, DQ) as compared with other developmental functions (> 70% DQ). The major difference between the children with FXS and those with autism was personal social function with a difference of 33% DQ. The average total CARS score were lower in children with FXS (average score, 28) than children with autism (average score, 34). Spearman's correlation demonstrated the CARS total score were negatively correlated with all developmental functions, except for gross motor function. Conclusions: Our findings suggest that the FXS children had multifaceted and disproportional development patterns in motor, speech and social domains when compared with the autism children without FXS. The developmental functions were inversely correlated with autistic profiles. Therefore, when applying comprehensive assessment, we were able to identify the special developmental features in children with FXS.