Rett Syndrome and HPA Axis Function: A Preliminary Investigation of Salivary Cortisol

Abstract

Rett syndrome (RTT) affects mostly females and results from a mutated gene (MECP2), which disrupts the production of a DNA binding protein called MeCP2 critical for neural development. Females with RTT have profound developmental disabilities including communicative and motor impairments and problems related to anxiety and arousal as well as difficulties with sleep, mood, and self-injurious behavior (SIB). It is plausible that perturbations to the neuroendocrine stress-response system (the hypothalamic-pituitary-adrenal [HPA] axis) may be associated with the reported behavioral disturbances in RTT. One approach to evaluating HPA axis integrity involves testing the diurnal pattern of salivary cortisol. In this study, following informed consent, saliva was collected during 2 days (at 4 time points: first wake, mid-morning, mid-afternoon, bedtime) from 22 females with RTT (M age = 13 yrs; 4-27). A questionnaire evaluating participant's sleep, mood, and SIB was completed by caregivers. Eighty percent of the sample had abnormal diurnal patterns and significant correlations were found between abnormal cortisol patterns and parent-reported concerns for SIB and mood. Results suggest that blunted cortisol production is related to HPA dysfunction and increased behavioral concerns.