Patients with cognitive deficits are routinely referred to clinical genetics for etiological work-ups including aCGH. We surveyed 7 cytogenetic centres in France and Switzerland, identifying 3870 patients ascertained for developmental delay and/or malformations. Also included in the study were a further 77 patients, ascertained on similar criteria, who were referred to the Department of Genetics, University of Tartu. These analyses were performed for clinical diagnostic purposes, all available phenotypic data (weight, height) being those provided anonymously by the clinician ordering the analysis. Consequently, research-based informed consent was not required by the institutional review board that approved the study.
