Background: While behavioural abnormalities are fundamental features of Rett syndrome (RTT), few studies have examined the RTT behavioural phenotype. Most of these reports have focused on autistic features, linked to the early regressive phase of the disorder, and few studies have applied standardised behavioural measures. We used a battery of…

Background: Marshall-Smith syndrome (MSS) is an infrequently described entity characterised by failure to thrive, developmental delay, abnormal bone maturation and a characteristic face. In studying the physical features of a group of patients, we noticed unusual behavioural traits. This urged us to study cognition, behavioural phenotype and…