Embryonal rhabdomyosarcoma in a patient with a heterozygous frameshift variant in the DICER1 gene and additional manifestations of the DICER1 syndrome

Germline mutations in the DICER1 gene are associated with an inherited cancer predisposition syndrome also known as the DICER1-syndrome, which is implicated in a broad range of tumors including pleuropulmonary blastoma, ovarian Sertoli-Leydig cell tumors, ciliary body medulloepithelioma (CBME), pituitary blastoma, embryonal rhabdomyosarcoma (eRMS), anaplastic renal sarcoma as well as ocular, sinonasal tumors ovarian sex-cord tumors, thyroid neoplasia and cystic nephroma. This study describes a novel, heterozygous frameshift DICER1 mutation in a patient, who is affected by different tumors of the DICER1-syndrome, including eRMS, CBME and suspected pleuropulmonary blastoma type I. By whole-exome sequencing of germline material using peripheral blood-derived DNA, we identified a single base pair duplication within the DICER1 gene (c.3405 dupA) that leads to a frameshift and results in a premature stop in exon 21 (p.Gly1136Arg). The metachronous occurrence of two unrelated tumor entities (eRMS and CBME) in a very young child within a short timeframe should have raised the suspicion of an underlying cancer susceptibility syndrome and should be prompt tested for DICER1.