Prader-Willi syndrome: From genetics to behaviour, with special focus on appetite treatments.

Prader-Willi syndrome (PWS) is a neurodevelopmental disorder resulting from a deletion in the expression of the paternally derived alleles in the region of 15q11-q13. PWS has a prevalence rate of 1:10,000-1:30,000 and is characterized by marked endocrine abnormalities including growth hormone deficiency and raised ghrelin levels. The hyperphagic phenotype in PWS is established over a number of phases and is exacerbated by impaired satiety, low energy expenditure and intellectual difficulties including obsessive-compulsive disorder and/or autistic behaviours. Clinical management in PWS typically includes familial/carer restriction and close supervision of food intake. If the supervision of food is left unmanaged, morbid obesity eventuates, central to the risk of cardiorespiratory disorder. None of the current appetite management/intervention strategies for PWS include pharmacological treatment, though recent research shows some promise. We review the established aberrant genetics and the endocrine and neuronal attributes which may determine disturbed regulatory processes in PWS. Focusing on clinical trials for appetite behaviours in PWS, we define the effectiveness of pharmacological treatments with a view to initiating and focusing research towards possible targets for modulating appetite in PWS.