Social behavior profile in young males with fragile X syndrome: Characteristics and specificity

Abstract

The present study characterizes distinctive and specific features of social behavior impairment, termed social behavior profile (SBP), in young males with fragile X syndrome (FraX). Fourteen males with FraX and autism (FraX+Aut), ages 3-8 years, were compared with either 41 FraX boys without autism (Aut), 7 age-matched males with developmental language delay and autism (DLD+Aut), or with 11 boys with non-selected (for language delay) idiopathic autism (IA), on several standardized instruments assessing social behavior and autistic features (i.e., autism diagnostic interview-revised, ADI-R). We found that FraX+Aut subjects displayed more impairment in overall cognition, problem/aberrant behavior, and adaptive behavior than the rest of the FraX cohort, even when individuals with pervasive developmental disorder (PDD) were included in the latter. Compared to both DLD+Aut and IA, FraX+Aut males were less impaired in ADI-R reciprocal social interaction (RECS) domain. However, boys with FraX+Aut were in general comparable to DLD+Aut subjects in problem/aberrant and adaptive behaviors. Based on the contrast between FraX+Aut and non-autistic FraX and DLD+Aut, we were able to identify measures (e.g., child behavior checklist (CBCL) withdrawn subscale) that better define social interaction impairment in FraX. Comparisons with DLD+Aut and IA led to the conclusion that communication impairment (COMM) and stereotypic behavior contribute relatively more to the diagnosis of autism in FraX+Aut. In agreement with recent studies, our data suggest that FraX+Aut, and more generally SBP, is a distinctive subphenotype among boys with FraX, which may share some pathophysiological mechanisms with IA.

What Can We Learn about Autism from Studying Fragile X Syndrome?

“…The basis for this would be that impairments in social and communicative behaviors occur in general at a lower rate in FXS (i.e., their FXS cohort was not divided according to DSM-IV categories) than in idiopathic ASD [19]. However, several other studies have not found clear behavioral differences between individuals with FXS and ASD and those with idiopathic ASD [10,12,20] (as discussed in the next section). Other features supportive of ASD as a distinctive entity in FXS include comorbid conditions, in particular the higher frequency of seizure disorder in individuals with FXS and ASD (i.e., 10–20% higher than in FXS alone) [21,22].…”

Autism Spectrum Disorders and Epigenetics

“…17 Numerous studies indicate that males with FXS and autism have lower IQs or are more developmentally delayed than males with FXS alone. [59][60][61][62] It is unclear which factors (e.g., reduced IQ) lead to apparently autistic behaviors in individuals with both FXS and ASD. As noted above, symptoms of ID and ASD may overlap considerably, often making it difficult to make a diagnosis of ASD in severely cognitively impaired individuals.…”

What Problematic Behaviors are Observed among Mentally Handicapped Children Receiving Pediatric Physical Therapy?

“…The ABC is used for many studies, including studies on syndrome phenotypes and pharmacotherapy effects. Outside Japan, many studies use ABC [6][7][8][9][10][11][12][13] . ABC has 58 questionnaire items in total: 15 irritability items, 16 lethargy items, 7 stereotypy items, 16 hyperactivity items, and 4 inappropriate speech items.…”