Here we report a 6p deletion of about 1 Mb encompassing five genes (ATXN1, DTNBP1, JARID2, MYLIP and GMPR), identified in a patient with severe ID, hypotonia, brain anomalies, EEG abnormalities, macrosomia, obesity, and ASDs with associated hyperactivity and behavioral abnormalities. This evidence concerns the gene DTNBP1 and obesity due to melanocortin 4 receptor deficiency.