eP318: Concurrent somatic 9p21 deletion and germline EP300 variant in a patient with T-ALL, immunodeficiency and malformations: Phenotypic expansion or comorbidities?

EP300 gene encodes E1A-associated protein p300 that function as co-activators of transcription and regulates transcription via chromatin remodeling. Pathogenic variants in EP300 on chromosome 22q13.2 have been reported in about 5–10% of individuals with Rubinstein-Taybi syndrome (RTS2) [OMIM# 613684], as well as in few patients with Menke-Hennekam syndrome (MKHK2) [OMIM# 618333]. In addition, it may function as a potential oncogene as somatic variants in EP300 have been reported in various cancers with high prevalence such as skin squamous cell carcinoma, marginal zone B-cell lymphoma, bladder carcinoma, and follicular lymphoma.