Diagnostic Usefulness of MLPA Techniques for Recurrent Copy Number Variants Detection in Global Developmental Delay/Intellectual Disability.

Background: Genetic testing has become a standardized practice in the diagnosis of patients with global developmental delay/intellectual disability (GDD/ID). The aim of this study is to observe the frequency of recurrent copy number variations (CNVs) in patients diagnosed with GDD/ID, using MLPA technique.

Methods: A total of 501 paediatric patients with GDD/ID were analysed using SALSA MLPA probemix P245 Microdeletion Syndromes-1A, and the technical steps were performed according to the MRC Holland MLPA general protocol.

Results: Twenty-five of 501 patients (5%) were diagnosed with a microdeletion/microduplication syndrome. Amongst them, 7 of 25 (30%) with clinical suggestion have a confirmed diagnosis, for the other cases the clinical features were not evocative for a specific syndrome.

Conclusion: This study showed that in cases with a specific clinical diagnosis the MLPA technique could be a useful alternative, less expensive and more efficient to indicate as first intention of a targeted diagnostic test, as it is the case of Williams syndrome, Prader-Willi syndrome or DiGeorge syndrome.