A 16p13.3 duplication syndrome has been recently suggested to be a novel recognizable syndrome as a reciprocal microduplication disease of Rubinstein-Taybi syndrome. The CREBBP gene is believed to be the dosage-sensitive critical gene responsible for the reciprocal duplication and deletion syndrome. Descriptions so far have been de novo. Here, we report a very rare case of a maternally inherited a -1 Mb sized duplication on 16p13.3 identified by SNP array testing. The patient showed moderate intellectual disability, normal growth, and characteristic facial features. The patient's mother also had mild intellectual disability, normal growth, camptodactyly, proximally implanted small thumbs, and distinctive facial features. The study provides additional information that furthers the understanding and delineation of 16p13.3 duplication syndrome.