- May 2022
DICER1 syndrome is a rare genetic disorder that predisposes individuals to multiple cancer types.
GeneName: DICER1 PMID: 29762508 HGNCID: N/A Inheritance Pattern: Autosomal dominant Disease Entity: Cancer Mutation: Germline Zygosity: Heterozygosity Variant: Unregistered Family Information: 12% of children with pleuropulmonary blastomas have cystic nephromas Case: 11 year old patient with Hodgkin lymphoma with DICER1 mutation in 2016.
DICER1 gene is located on chromosome 14q32.13 and plays a crucial role in the control of protein translation; its product, dicer protein, is a ribonuclease (RNase) III endoribonuclease which is essential for the production of microRNAs (miRNA) which are formed by the cleavage of pre-miRNA or double-stranded RNA1–4. RNase III contains two domains, IIIa and IIIb which cleave 3p miRNA and 5p miRNA from the 3′ and 5′ pre-miRNA, respectively. These cleavages require magnesium ions at the interface between the IIIa and IIIb domains and the miRNA; this magnesium dependent catalytic processing occurs at specific residues, E1320, E1564, E1813 and D17092–4. miRNA has a pivotal role in regulating the expression of over 30% of protein-coding genes by its interaction with mRNA5. Given the impact of DICER1 in post-translational events, it is not entirely surprising that functional DICER1 is essential for vertebrate development as evidenced by developmental arrest and death of the embryo when both alleles are lost6,7. Conceptually, DICER1 can be regarded as either a tumor suppressor gene due to loss-of-function mutations or an oncogene due to gain-of-function mutations; it is thought to function as a haploinsufficient tumor suppressor gene with the loss of one allele leading to tumor progression but loss of both alleles having an inhibitory effect for tumor development implying that one intact allele is needed for cell survival8.A study led by one of the authors (DAH) identified germline loss-of-function DICER1 mutations affecting the RNase IIIb domain in affected families with pleuropulmonary blastoma (PPB)9, a rare dysembryonic lung malignancy of childhood which was not the only manifestation of this familial tumor predisposition syndrome; germline and somatic DICER1 mutations were subsequently identified in several other familial associated tumors in several extrapulmonary sites (Table 1). Individuals with germline DICER1 mutations also had non-neoplastic conditions including macrocephaly, renal structural anomalies, retinal abnormalities, dental perturbations, and the GLOW syndrome (global developmental delay, lung cysts, overgrowth and Wilms tumor). These associations encircle the DICER1 tumor predisposition syndrome (Online Mendelian Inheritance in Man numbers 606241, 601200 and 138800), with the estimation that 90% of those affected by this syndrome inherited a germline mutation from one of their parents, with a pattern of autosomal dominant inheritance10.
- Gene Name: DICER1 Syndrome (OMIM 606241, 601200)
- PMID: 34599283
- Hugo Gene Nomenclature Committee (HGNCID): N/A
- Inheritance Pattern: Autosomal Dominant
- Disease Entity: pleuropulmonary blastoma (PPB), Sertoli-Leydig cell tumor, gynandroblastoma, embryonal rhabdomyosarcomas of the cervix and other sites, multinodular goiter, differentiated and poorly differentiated thyroid carcinoma, cervical-thyroid teratoma, cystic nephroma-anaplastic sarcoma of kidney, nasal chondromesenchymal hamartoma, intestinal juvenile-like hamartomatous polyp, ciliary body medulloepithelioma, pituitary blastoma, pineoblastoma, primary central nervous system sarcoma, embryonal tumor with multilayered rosettes-like cerebellar tumor, PPB-like peritoneal sarcoma, DICER1-associated presacral malignant teratoid neoplasm and other non-neoplastic associations.
- Mutation: Germline
- Zygosity: Heterozygous
- Variant: has multiple variants associated with it
- Family Information: Germ cell tumors have been reported in family members
- Case: identified affected families w/ pleuropulmonary blastoma (PPB): germline and somatic DICER1 mutations also identified in other familial associated tumors
- CasePreviousTesting: numerous studies confirmed relationship b/t DICER1 variants in carriers and development of range neoplasms and non-neoplastic conditions
DICER1 variants cause a hereditary cancer predisposition
-Gene: DICER1 -PMID: 29343557 -Inheritance Pattern: DICER1 is inherited as an autosomal dominant condition with decreased penetrance -Disease Entity: earlier onset disease, multisite disease, 0-2 site disease, cystic lung disease, familial disease, bilateral disease, stage IA/IB, bilateral disease -mutation: germline loss-of-function mutation, missense mutation, Intronic mutations, hotspot mutation, second somatic mutation, truncating mutations, biallelic mutation -zygosity: heterozygosity -Family History: -testing should be considered for those with a family history of DICER1-associated conditions so that appropriate surveillance can be undertaken. -Individuals at 50% risk of a germline pathogenic variant based on family history who do not pursue genetic testing should follow surveillance guidelines as -if they have a DICER1 mutation unless/until genetic testing confirms that they did not inherit the familial mutation When a pulmonary cyst is identified in a young child with a pathogenic germline -DICER1 variant or family history of a DICER1-associated condition, it should be assumed to be Type I PPB until proven otherwise
Other Information: -Case: Risk for most DICER1-associated neoplasms is highest in early childhood and decreases in adulthood -affected phenotype may simply result from probabilities of generating the characteristic “loss-of-function plus hotspot” two hit typical of a DICER1 syndrome neoplasm. -Caseprevioustesting: presymptomatic testing of a minor child, should be discussed and factored into the decision process, as some individuals may choose, and have the right to choose, not to know their/their child’s genetic status. -gnomAD: n/a
- Apr 2022
Health care providers may consider the presence of DICER1 pathogenic variants when a female presents with a personal or family history of ovarian sex cord-stromal tumor
FAMILY INFORMATION: FEMALE PATIENTS WITH A PERSONAL OR FAMILY HISTORY OF OVARIAN TUMORS
- Mar 2021
affected boy (IV-1; 11 years)
Case#: IV-1, male, 11 y.o, Pakistani
DiseaseAssertion: Limb-girdle muscular dystrophy (LGMD2F), sarcoglycanopathy
FamilyInfo: Consanguineous parents, both described as healthy and showing no abnormality. Three unaffected siblings were also reported: IV-2 (male, 10 y.o), IV-4 (male, 7 y.o), and IV-5 (female, 1.5 y.o). A deceased sister is included on the pedigree, but no details about this individual were reported. See Figure 1.
CasePresentingHPOs: HP:0001288, HP:0002650, HP:0003547, HP:0003749, HP:0001655
CaseHPOFreeText: Reduced weight gain noted at 3-4 y.o. Mild cardiac hypertrophy observed on cardiac review (additional echocardiography results reported in "Echocardiography" section). Additional phenotypic information reported in Supplementary Table 1.
CaseNotHPOs: HP:0009077, HP:0000703, HP:0001382, HP:0000365, HP:0001510, HP:0001249, HP:0000478, HP:0030148, HP:0011675
CaseNotHPOFreeText: Extensor muscles of the wrist, toes flexors, and hip abductors noted to be relatively normal. Additional phenotypic information reported in Supplementary Table 1.
MotorAchievement: Sat without assistance at 8 months of age, walked at 15 months of age, ran at 1.5 months of age. Never jumped or hopped. Frequent falls noted, as well as difficulty in walking and climbing stairs since 3 y.o.
CreatineKinase: 18SU (normal: 20SU for children, 10SU for adults) (see Supplementary Table 1). No assertion was made by the authors regarding whether this represents a normal or decreased CK level.
PreviousTesting: Thyroid stimulating hormone: 2.3mU/L (normal: <0.6mU/L); Serum VZV IgG: 286mlU/ml (normal: >150mlU/ml); IGF-1:186 ng/μl (normal: 102-520 ng/μl for males, 14 y.o); PRL: 202 ng/dl (normal: 42.5-414 ng/dl for males); Vitamin D: 47nmol/L (normal: 25-50 nmol/L); Free T4: 17.0 pmol/L (normal:10.8-19.0 pmol/L) (see Supplementary Table 1)
GenotypingMethod: (1) Targeted next generation sequencing of 31 genes associated with LGMD from proband genomic DNA extracted from peripheral blood sample; (2) Sanger sequencing of genomic DNA extracted from peripheral blood samples to confirm SGCD variant of interest in proband and three family members (III-3, III-4, IV-4). Variant was identified in homozygosity in the proband, in heterozygosity in each of the parents, and was not present in the unaffected sibling (IV-4).
Variant: NM_000337.5:c.289C>T (p.Arg97Ter)
gnomAD: Not reported
- Jan 2021
CaseAJV: 17 years diagnosis, Australia
DiseaseAssertion: Hypertrophic Cardiomyopathy
FamilyInfo: Father (index case) died awaiting cardiac transplant (carried both variants). Two possibly affected relatives.
CasePresentingHPOs: HP:0001639, HP:0006536
(Hypertrophic cardiomyopathy, Obstructive lung disease)
HPOsFreeText: Maximum left ventricular hypertrophy at 17 mm, Sudden cardiac death event at 17 years, Maximal wall thickness at 22mm,
CasePreviousTesting: See Table 1
CaseGenotypingMethod: DNA was isolated from peripheral blood. Most participants underwent testing from the Illumina Cardiomyopathy Sequencing Panel, which includes 46 cardiomyopathy related genes. For others, whole exome sequencing or Sanger squencing was used. After the results were returned, variants were filtered for pathogenicity and rarity.
gnomAD: Not in gnomAD
Multiple Gene Variants:
Variant: NM_000256.3:c.2980C>T (p.Leu994Phe)
gnomAD: European (Non-Finnish) 1.624e-4, Overall 8.461e-5 https://gnomad.broadinstitute.org/variant/11-47355487-G-A