Rubinstein-Taybi syndrome in a Saudi boy with distinct features and variants in both the CREBBP and EP300 genes: a case report

• Published in: BMC medical genetics 2019-01, Vol.20 (1), p.12-12, Article 12
• Main Authors: Al-Qattan, Mohammad M, Jarman, Abdulaziz, Rafique, Atif, Al-Hassnan, Zuhair N, Al-Qattan, Heba M
• Format: Article
• Language: English
• Subjects: Amino acid substitution; Benign; Brachydactyly; Case Report; Case reports; Child, Preschool; CREB-Binding Protein - genetics; CREBBP; Defects; Dysmorphology; E1A-Associated p300 Protein - genetics; EP300; Exons; Fingers & toes; Gene mutation; Genes; Genetic Association Studies; Genetic research; Genetic Testing; Genotype & phenotype; Heterozygote; High-Throughput Nucleotide Sequencing; Humans; Intellectual disabilities; Lip; Male; Mutation; Nervous system; Patients; Phenotype; Phenotypes; Proteins; Risk factors; Rubinstein-Taybi syndrome; Rubinstein-Taybi Syndrome - genetics; Rubinstein-Taybi Syndrome - physiopathology; Saudi Arabia; Sequence Analysis, DNA
• ISSN: 1471-2350; 1471-2350
• DOI: 10.1186/s12881-019-0747-5

Rubinstein-Taybi syndrome (RSTS) Type 1 (OMIM 180849) is characterized by three main features: intellectual disability; broad and frequently angulated thumbs and halluces; and characteristic facial dysmorphism. We report on a Saudi boy with RSTS Type 1 and the following distinct features: a midline notch of the upper lip, a bifid tip of the tongue, a midline groove of the lower lip, plump fingers with broad / flat fingertips, and brachydactyly. The child was found to be heterozygous in the CREBBP gene for a sequence variant designated c.4963del, which is predicted to result in premature protein termination p.Leu1655Cysfs*89. The child and his father were also found to be heterozygous in the EP300 gene for a sequence variant designated c.586A > G, which is predicted to result in the amino-acid substitution p.Ile196Val. Our report expands the clinical spectrum of RSTS to include several distinct facial and limb features. The variant of the CREBBP gene is known to be causative of RSTS Type 1. The variant in the EP300 gene is benign since the father carried the same variant and exhibited no abnormalities. However, functional studies are required to investigate if this benign EP300 variant influences the phenotype in the presence of disease-causing CREBBP gene mutations.