ESPE Abstracts

Background: DICER1, a ribonuclease, cleaves non-coding small RNA precursors to generate mature microRNAs (miRNAs), of ~21 nucleotides in length. MiRNAs alter gene expression post-transcriptionally by directly binding to mRNA transcripts and subsequently down-regulating gene expression. It is estimated that expression of ~30–70% of all mammalian protein-coding genes are regulated in this manner.

Method: Sequencing of DICER1 in various tumors, accompanied by studies in RNA and protein.

Results: We have identified germ-line and/or somatic DICER1 mutations in those affected by pleuropulmonary blastoma, cystic nephroma, Sertoli–Leydig cell tumors, cervical rhabdomyosarcoma, Wilms tumor, anaplastic sarcoma of the kidney, pituitary blastoma, pineoblastoma, nasal chondromesenchymal hamartoma, gonadal germ cell tumors, multinodular goitre and differentiated thyroid cancer. While the germ-line mutations are generally truncating and are widely scattered across the gene, remarkably, nearly all the somatic mutations affect key metal-binding amino acids within the RNase IIIb domain and likely alter miRNA production.

Conclusion: DICER1 syndrome is a recently discovered syndrome with a mainly pediatric, adolescent and young adult presentation. I will review the syndrome, with a focus on pediatric and endocrinological manifestations.