Evaluation of the hypothalamic-pituitary-adrenal axis and its relationship with central respiratory dysfunction in children with Prader-Willi syndrome.

BACKGROUND: Children with Prader-Willi Syndrome (PWS) have been considered at risk for central adrenal insufficiency (CAI). Hypothalamic dysregulation has been proposed as a common mechanism underlying both stress-induced CAI and central respiratory dysfunction during sleep. OBJECTIVE: To evaluate CAI and sleep-related breathing disorders in PWS children. PATIENTS AND METHODS: Retrospective study of cortisol response following either insulin tolerance test (ITT) or glucagon test (GT) in 20 PWS children, and comparison with 33 non- Growth Hormone deficient (GHD) controls. Correlation between sleep related breathing disorders and cortisol response in 11 PWS children who received both investigations. RESULTS: In PWS children, the cortisol peak value showed a significant, inverse correlation with age (Kendall's τ = -0.411; p = 0.012). A similar though non-significant correlation was present between cortisol increase and age (τ = -0.232; p = 0.16). Similar correlations were found in controls. In only 1 of 20 PWS children (5 %), ITT was suggestive of CAI. Four patients had an elevated central apnea index but they all exhibited a normal cortisol response. No relationship was found between peak cortisol or cortisol increase and central apnea index (respectively p = 0.94 and p = 0.14) or the other studied polysomnography (PSG) parameters. CONCLUSIONS: CAI assessed by ITT/GT is rare in PWS children. Our data do not support a link between CAI and central respiratory dysregulation.

Behaviour problems and relationships with family and peers during adolescence.

This study examines the relationship between (a) characteristics of adolescents' social networks, personal resources, and environmental risks; and (b) adolescents' behaviour problems. A socio-ecological perspective was used to determine whether social support and perceived conflict operate as risk or protective factors. Three samples of adolescents were studied: 63 adolescents in residential care; 29 in day treatment; and 63 who had had no contact with professional care. Interrelations were explored by means of structural equation modelling. Social support in family and peer group may operate as a risk factor or a protective factor depending on other risk factors in these subsystems. Perceived conflict is related to behaviour problems, although the influence differs depending on environmental risk factors and the type of behaviour problems.