A rare PALB2 germline variant causing G2/M cell cycle arrest is associated with isolated myelosarcoma in infancy

Abstract

Abstract Background Isolated myelosarcoma of infancy is a rare presentation of acute myelogenous leukaemia (AML). Because of its rarity and early onset in infancy underlying genetic predisposition is potentially relevant in disease initiation. Methods and Results We report an oncologic emergency in an infant with thoracic and intraspinal aleukaemic myeloid sarcoma causing acute myelon compression and lower leg palsy. Whole‐exome sequencing of the patient's germline DNA identified a rare PALB2 (OMIM 610355) variant (p.A1079S), which is located in a domain critical for the gene's proper function within the homology‐directed repair pathway. In line with potential DNA damage repair defects mediated by the PALB2 deregulation, the patient's fibroblasts showed increased sensitivity towards radiation and DNA intercalating agents. Conclusion Therefore, we suggest PALB2 p.A1079S as a pathogenic variant potentially contributing to the here observed patient phenotype.

Keywords

• extramedullary myelogenous leukaemia
• myeloid sarcoma
• tumour suppressor
• PALB2