This test analyzes the DICER1 gene. Pathogenic variants in this gene are associated with DICER1 syndrome, also known as DICER1-pleuropulmonary blastoma familial tumor predisposition syndrome. This condition causes benign and malignant tumors in the lungs, kidneys, ovaries, and thyroid.
Genetic testing of this gene may confirm a diagnosis and help guide treatment and management decisions. Identification of a disease-causing variant would also guide testing and diagnosis of at-risk relatives. This test is specifically designed for heritable germline mutations and is not appropriate for the detection of somatic mutations in tumor tissue.
DICER1 can also be ordered as part of a broader panel to test for different types of hereditary cancer conditions. Depending on the individual’s clinical and family history, one of these broader panels may be appropriate. Any of these broader panels can be ordered for no additional charge.
DICER1 syndrome is an inherited disorder associated with an increased risk of both malignant and benign tumors that most often occur in the lungs, kidneys, ovaries, and thyroid. Tumors of the pituitary and pineal gland can also develop. However, it appears that many who carry a pathogenic variant never develop tumors.
Most of the associated tumors, including pleuropulmonary blastoma and cystic nephroma, present in childhood. Females can develop ovarian sex cord-stromal tumors, which include Sertoli-Leydig cell tumors, juvenile granulosa cell tumors, and gynandroblastoma. Adults with DICER1 syndrome may develop multinodular goiter, adenomas, and/or differentiated thyroid cancer.
Less frequently observed tumors associated with this condition include, ciliary body medulloepithelioma, botryoid-type embryonal rhabdomyosarcoma, nasal chondromesenchymal hamartoma, pituitary blastoma, and pineoblastoma.
Due to the rarity of DICER1 syndrome and the fact that some individuals with a pathogenic variant will never develop symptoms, the specific lifetime risk of developing DICER1-related tumors is unknown. Many of the tumors develop in childhood and most present before the age of 40. Ovarian sex cord-stromal tumors are limited to females and thyroid pathology typically presents in adulthood.
Sequencing analysis detects a pathogenic variant in DICER1 in 65% of affected individuals. While deletion/duplication analysis is also performed, the proportion of cases due to DICER1 copy number variants is currently not established.
Autosomal dominant. Most cases of DICER1 syndrome are inherited from a parent; approximately 20% occur as the result of a spontaneous de novo mutation.
The prevalence of DICER1 syndrome is currently unknown and appears to be rare. With the exception of thyroid pathology, tumors associated with this condition are very rare.
Analysis of the DICER1 gene may be considered in individuals with:
Invitae is a College of American Pathologists (CAP)-accredited and Clinical Laboratory Improvement Amendments (CLIA)-certified clinical diagnostic laboratory performing full-gene sequencing and deletion/duplication analysis using next-generation sequencing technology (NGS).
Our sequence analysis covers clinically important regions of each gene, including coding exons, +/- 10 base pairs of adjacent intronic sequence in the transcript listed below. In addition, analysis covers the select non-coding variants specifically defined in the table below. Any variants that fall outside these regions are not analyzed. Any specific limitations in the analysis of these genes are also listed in the table below.
Based on validation study results, this assay achieves >99% analytical sensitivity and specificity for single nucleotide variants, insertions and deletions <15bp in length, and exon-level deletions and duplications. Invitae's methods also detect insertions and deletions larger than 15bp but smaller than a full exon but sensitivity for these may be marginally reduced. Invitae’s deletion/duplication analysis determines copy number at a single exon resolution at virtually all targeted exons. However, in rare situations, single-exon copy number events may not be analyzed due to inherent sequence properties or isolated reduction in data quality. Certain types of variants, such as structural rearrangements (e.g. inversions, gene conversion events, translocations, etc.) or variants embedded in sequence with complex architecture (e.g. short tandem repeats or segmental duplications), may not be detected. Additionally, it may not be possible to fully resolve certain details about variants, such as mosaicism, phasing, or mapping ambiguity. Unless explicitly guaranteed, sequence changes in the promoter, non-coding exons, and other non-coding regions are not covered by this assay. Please consult the test definition on our website for details regarding regions or types of variants that are covered or excluded for this test. This report reflects the analysis of an extracted genomic DNA sample. In very rare cases, (circulating hematolymphoid neoplasm, bone marrow transplant, recent blood transfusion) the analyzed DNA may not represent the patient's constitutional genome.
|Gene||Transcript reference||Sequencing analysis||Deletion/Duplication analysis|