Neurodevelopmental profile and stages of regression in Phelan-McDermid syndrome.

Aim: To characterize the neurodevelopmental profile of patients with Phelan-McDermid syndrome (PMS) and describe the nature and trajectory of regression.

Method: This was a retrospective, monocentric study examining the clinical and developmental data of 24 patients (average age = 25 years 6 months, range = 6-56 years, n = 13 males) with a confirmed 22q13.3 terminal deletion carried out at the Centre for Human Genetics, University Hospital Leuven.