Here we describe a further eight affected individuals (thus more than doubling the number of documented cases of this rare pathological entity) and compare these to previously reported cases of MEGF8- and RAB23-associated CRPTS, emphasising that the core clinical features are similar between RAB23 and MEGF8 patients, but demonstrating that laterality defects are more common, and craniosynostosis appears less severe, in the MEGF8-associated form of the condition. This evidence concerns the gene RAB23 and craniosynostosis.