Whole exome sequencing reveals a novel LRBA mutation and clonal hematopoiesis in a common variable immunodeficiency patient presented with hemophagocytic lymphohistiocytosis.

Common variable immunodeficiency (CVID) was a kind of primary immunodeficiency disorders with heterogeneous phenotype and genotype. Lipopolysaccharide-responsive and beige-like anchor (LRBA) mutation was identified as disease associated in CVID, advanced genetic method will help to detect atypical cases. We report a case of adult patient manifested as hemophagocytic lymphohistiocytosis (HLH), bone marrow examination suggested prosperity to MDS, manifested as increased immature myeloid cells and dysplastic hematopoiesis. Whole exome sequencing (WES) identified a novel heterogeneous c.1876T > C (p.W626R) mutation in LRBA and four somatic mutations: ASXL1 (c.1967dupA); PTPN11 (c.226G > A), U2AF1 (c.101C > T and c.470A > G), among which ASXL1 was a high-risk marker of clonal hematopoiesis. Combined with her recurrent severe infections and immune abnormalities such as hypoimmunoglobulinemia, the patient was diagnosed with CVID. Subsequent hematopoietic stem cell transplantation saved her from severe cytopenia and immune deficiency. This case report highlights the great promise of utilization of WES for diagnosing rare disease with atypical manifestations and guiding further treatment.