16p13.3 deletion syndrome is a rare fetal chromosome abnormality that can cause malformations and deformations in multiple body organs. Chromosome 16p13.3 band contains several genes like CREBBP, DNASE1, and TRAP1, 3, but CREBBP is completely or partially deleted in all the cases. Some studies state that 16p13.3 deletion syndrome is a contiguous gene syndrome (Bartsch et al. 2006). However, as no significant differences in the phenotypes exist (Blough et al. 2000; Rusconi et al. 2015; Pérez-Grijalba et al. 2019), there are some controversies about whether it is a different entity from Rubinstein-Taybi syndrome (RSTS), caused by point mutations or deletions within the CREBBP gene. The prominent features of both syndromes are postnatal growth retardation, moderate to severe mental retardation, special facial deformities, and broad and angulated thumbs and halluces.