Children suffering from intellectual disability, dysmorphic features and organ-specific developmental abnormalities should undergo genetic testing. Entities such as X fragile syndrome should be investigated. If we add obesity to the “equation”, Prader-Willi and Bardet-Biedl are thus far the most common syndromic conditions to be found. The evolution of genetic testing brought several other genetic determinants of developmental delay. We report on a 4-year-old girl presenting with obesity and delayed neurological, cognitive and motor development whose genetic testing by array-based comparative genomic hybridization exposed a partial deletion at chromosome 2p25.3, containing the gene MYT1L.