We contacted Koolen et al. [44] about his patient and learned that, after publication, the patient was re-evaluated by SNP array, which confirmed that the 6p25 variant was benign and identified a pathogenic deletion of EHMT1 (euchromatic histone methyltransferase 1 MIM*607001, chr 9q34.3), leading to a diagnosis of Kleefstra syndrome (MIM#610253) (personal communication Koolen et al.). This evidence concerns the gene EHMT1 and Kleefstra syndrome.