Cortisol and behavior in fragile X syndrome

OBJECTIVE

The purpose of this study was to determine if children with fragile X syndrome, who typically demonstrate a neurobehavioral phenotype that includes social anxiety, withdrawal, and hyper-arousal, have increased levels of cortisol, a hormone associated with stress. The relevance of adrenocortical activity to the fragile X phenotype also was examined.

METHOD

One hundred and nine children with the fragile X full mutation (70 males and 39 females) and their unaffected siblings (51 males and 58 females) completed an in-home evaluation including a cognitive assessment and a structured social challenge task. Multiple samples of salivary cortisol were collected throughout the evaluation day and on two typical non-school days. Measures of the fragile X mental retardation (FMR1) gene, child intelligence, the quality of the home environment, parental psychopathology, and the effectiveness of educational and therapeutic services also were collected. Linear mixed-effects analyses were used to examine differences in cortisol associated with the fragile X diagnosis and gender (fixed effects) and to estimate individual subject and familial variation (random effects) in cortisol hormone levels. Hierarchical multiple regression analyses were conducted to determine whether adrenocortical activity is associated with behavior problems after controlling for significant genetic and environmental factors.

RESULTS

Results showed that children with fragile X, especially males, had higher levels of salivary cortisol on typical days and during the evaluation. Highly significant family effects on salivary cortisol were detected, consistent with previous work documenting genetic and environmental influences on adrenocortical activity. Increased cortisol was significantly associated with behavior problems in boys and girls with fragile X but not in their unaffected siblings.

CONCLUSIONS

These results provide evidence that the function of the hypothalamic-pituitary-adrenal axis may have an independent association with behavioral problems in children with fragile X syndrome.

The influence of environmental and genetic factors on behavior problems and autistic symptoms in boys and girls with fragile X syndrome

OBJECTIVE

Fragile X syndrome, caused by mutations in a single gene of the X chromosome (FMR1), is associated with neurobehavioral characteristics including social deficits with peers, social withdrawal, gaze aversion, inattention, hyperactivity, anxiety, depression, and autistic behavior. However, there is considerable variability in the behavioral and psychiatric problems among children with this condition. The purpose of this study was to measure genetic and environmental factors influencing behavior problems and autistic symptoms in children with fragile X syndrome.

DESIGN

We conducted an in-home evaluation of 120 children (80 boys and 40 girls) with the fragile X full mutation and their unaffected siblings, including measurements of the FMR1 protein (FMRP), quality of the home environment, maternal and paternal psychopathology, effectiveness of educational and therapeutic services, and child behavior problems.

RESULTS

Results of multiple regression analyses showed that for boys with fragile X, effectiveness of educational and therapeutic services and parental psychological problems predicted internalizing and externalizing types of problems, while the quality of the home environment predicted autistic behavior. For girls with fragile X, the results emphasized significant effects of FMRP on behavior, in particular social withdrawal and anxious/depressed behavior.

CONCLUSIONS

These findings are among the first to link FMRP expression to behavior. They also emphasize the significance of home- and school-based environmental variables in the neurobehavioral phenotype and help to lay the foundation for studies designed to identify specific interventions for reducing problem behavior in children with fragile X syndrome.

Manual-Driven group cognitive-behavioral therapy for adolescents with obsessive-compulsive disorder: a pilot study

OBJECTIVE

Concerns about isolation, compromised development, partial pharmacotherapy response, therapist scarcity, and inadequate cognitive-behavioral therapy (CBT) adherence led the authors to adapt a CBT protocol to a group format for adolescents with obsessive-compulsive disorder (OCD). A naturalistic, open trial of group CBT for adolescent OCD is described. The authors predicted symptom improvement and format acceptability.

METHOD

Over a 1 -year period, 18 adolescents aged 13 to 17 years with OCD received 14-week group CBT based on March and Mulle's OCD in Children and Adolescents: A Cognitive-Behavioral Treatment Manual in four consecutive sessions of five to nine patients. Eighty-three percent had undergone at least one medication trial, and 78% had previous CBT experience.

RESULTS

OCD symptoms measured by the Children's Yale-Brown Obsessive Compulsive Scale improved significantly, both statistically and clinically. Adolescents consistently shared information and designed exposure interventions for themselves and others during sessions. Repeated self-report measures confirmed adolescents' satisfaction with therapy.

CONCLUSIONS

This pilot study demonstrates that a manual-based treatment protocol may be exported for clinical use, adaptable for the end-user's needs, and palatable to adolescent patients. Clinical improvement and patient satisfaction justify further investigation in a controlled study.

Neurobehavioral phenotype in carriers of the fragile X premutation

There have been contradictory findings in the fragile X (fraX) literature about possible neurocognitive and psychological symptoms due to the fraX premutation (pM). The purpose of the present study was to investigate the relationship between CGG repeat length and neurobehavioral functioning in carriers of the fraX pM. Eighty-five female carriers of the pM with allele sizes ranging from 59-166 were administered a comprehensive IQ test (WAIS-III) and completed a questionnaire designed to measure psychopathology (Symptom Checklist (SCL)-90-R). No relationship between allele size and cognition was identified. A significant negative relationship between allele size and age was found, as well as a positive relationship between allele size and depression. Follow-up analyses separating small and large allele sizes (below and above 100 CGG repeats) indicated that individuals with larger allele sizes scored significantly higher on the Interpersonal Sensitivity and Depression subscales of the SCL-90-R. Despite the limitation of few individuals with high CGG repeat lengths, our findings suggest that females with larger premutated alleles (> or = 100 repeats) display some clinical manifestations of fraX syndrome.

Functional neuroanatomy of visuo-spatial working memory in Turner syndrome

Turner syndrome (TS), a genetic disorder characterized by the absence of an X chromosome in females, has been associated with cognitive and visuo-spatial processing impairments. We utilized functional MRI (fMRI) to investigate the neural substrates that underlie observed deficits in executive functioning and visuo-spatial processing. Eleven females with TS and 14 typically developing females (ages 7-20) underwent fMRI scanning while performing 1-back and 2-back versions of a standard visuo-spatial working memory (WM) task. On both tasks, TS subjects performed worse than control subjects. Compared with controls, TS subjects showed increased activation in the left and right supramarginal gyrus (SMG) during the 1-back task and decreased activation in these regions during the 2-back task. In addition, decreased activation in the left and right dorsolateral prefrontal cortex (DLPFC) and caudate nucleus was observed during the 2-back task in TS subjects. Activation differences localized to the SMG, in the inferior parietal lobe, may reflect deficits in visuo-spatial encoding and WM storage mechanisms in TS. In addition, deficits in the DLPFC and caudate may be related to deficits in executive function during WM performance. Together these findings point to deficits in frontal-striatal and frontal-parietal circuits subserving multiple WM functions in TS.

Functional neuroanatomy of visuospatial working memory in fragile X syndrome: relation to behavioral and molecular measures

OBJECTIVE

Fragile X syndrome is a neurogenetic disorder that is the most common known heritable cause of neurodevelopmental disability. This study examined the neural substrates of working memory in female subjects with fragile X syndrome. Possible correlations among behavioral measures, brain activation, and the FMR1 gene product (FMRP expression), as well as between IQ and behavioral measures, were investigated.

METHOD

Functional magnetic resonance imaging was used to examine visuospatial working memory in 10 female subjects with fragile X syndrome and 15 typically developing female subjects (ages 10-23 years). Subjects performed standard 1-back and 2-back visuospatial working memory tasks. Brain activation was examined in four regions of the cortex known to play a critical role in visuospatial working memory. Correlations between behavioral, neuroimaging, and molecular measures were examined.

RESULTS

Relative to the comparison group, subjects with fragile X syndrome performed significantly worse on the 2-back task but not on the 1-back task. In a region-of-interest analysis focused on the inferior frontal gyrus, middle frontal gyrus, superior parietal lobule, and supramarginal gyrus, comparison subjects showed significantly increased brain activation between the 1-back and 2-back tasks, but subjects with fragile X syndrome showed no change in activation between the two tasks. Significant correlations were found in comparison subjects between activation in the frontal and parietal regions and the rate of correct responses on the 2-back task, but not on the 1-back task. In subjects with fragile X syndrome, significant correlations were found during the 2-back task between FMRP expression and activation in the right inferior and bilateral middle frontal gyri and the bilateral supramarginal gyri.

CONCLUSIONS

Subjects with fragile X syndrome are unable to modulate activation in the prefrontal and parietal cortex in response to an increasing working memory load, and these deficits are related to a lower level of FMRP expression in fragile X syndrome subjects than in normal comparison subjects. The observed correlations between biological markers and brain activation provide new evidence for links between gene expression and cognition.