Chromosome 16p13.3 Contiguous Gene Deletion Syndrome including the SLX4, DNASE1, TRAP1, and CREBBP Genes Presenting as a Relatively Mild Rubinstein–Taybi Syndrome Phenotype: A Case Report of a Saudi Boy

Table 2

Phenotypes related to the CREBBP gene.

Given name	OMIM	Deletion/mutation/duplication of the CREBBP gene	Phenotype
Classic Rubinstein–Taybi Type I syndrome	180849	Usually deletions or truncating mutations	Characteristic facial dysmorphism, variable intellectual disability, broad/angulated thumbs, and halluces. Other systemic abnormalities (such as cardiac defects) are frequent.
The incomplete (mild) Rubinstein–Taybi Type I syndrome	—	Usually missense or mosaic mutations	The facial and the thumb/big toe features are similar to the classic type. However, there is usually mild or no intellectual disability. Other systemic defects are usually absent.
16p13.3 contiguous deletion syndrome	610543	Large deletions including the CREBBP gene and the 3′ adjacent genes	Controversial issue in the literature. Some believe that the phenotype is more severe and is associated with severe/fatal infections, while others could not find a correlation between the size of the deletion and the phenotypic severity. Our case was unique because of the relatively mild phenotype.
16p13.3 contiguous duplication syndrome	613458	Duplication of the CREBBP and other adjacent genes	Classic facial dysmorphism and mild to moderate intellectual disability. However, the thumbs are proximally displaced instead of being broad and angulated.