A rare syndromic endocrine disease characterized by childhood-onset hyperphagia and obesity, alveolar hypoventilation, dysautonomia, hypothalamic dysfunction and neurobehavioral disorders. Central hypothyroidism, endocrine anomalies, electrolyte imbalances and respiratory failure may also be associated.

Occipitofrontal (head) circumference greater than 97th centile compared to appropriate, age matched, sex-matched normal standards. Alternatively, a apparently increased size of the cranium.