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3
Inheritance
3
Pathophys.
12
Phenotypes
1
Gaps
26
Pathograph
17
Genes
5
Medical Actions
16
Subtypes
1
References
1
Deep Research
👪

Inheritance

3
X-linked recessive inheritance HP:0001419
X-linked recessive inheritance applies to DKC1, the gene encoding dyskerin and historically the most common and most severe form of classic DC.
X-linked recessive inheritance
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"The mode of inheritance of DC/TBD varies by gene: X-linked: DKC1."
GeneReviews assigns X-linked inheritance specifically to DKC1.
Autosomal dominant inheritance HP:0000006
Autosomal dominant inheritance applies to NAF1, RPA1, TERC, TINF2, and ZCCHC8, and is the most frequent mode in adult-onset (cryptic) TBD.
Autosomal dominant inheritance
Show evidence (2 references)
PMID:20301779 SUPPORT Human Clinical
"Autosomal dominant: NAF1, RPA1, TERC, TINF2, and ZCCHC8."
GeneReviews lists the autosomal dominant DC/TBD genes.
PMID:38066848 SUPPORT Human Clinical
"TBD genetic etiology includes all modes of inheritance, with autosomal dominant the most frequent in adult-onset disease."
Autosomal dominant inheritance predominates in adult-onset TBD.
Autosomal recessive inheritance HP:0000007
Autosomal recessive inheritance applies to CTC1, NHP2, NOP10, POT1, STN1, and WRAP53; ACD, PARN, RTEL1, and TERT can be inherited as either dominant or recessive.
Autosomal recessive inheritance
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"Autosomal recessive: CTC1, NHP2, NOP10, POT1, STN1, and WRAP53."
GeneReviews lists the autosomal recessive DC/TBD genes.

Subtypes

16
X-linked DC (DKC1, dyskerin)
DKC1 hgnc:2890 X-linked recessive inheritance
X-linked recessive DC caused by pathogenic variants in DKC1 encoding dyskerin, a core component of the H/ACA small nucleolar ribonucleoprotein required for pseudouridylation and for stability of the telomerase RNA component. DKC1 disease is historically the most common and most severe classic DC form, including Hoyeraal-Hreidarsson syndrome.
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"The mode of inheritance of DC/TBD varies by gene: X-linked: DKC1."
GeneReviews assigns X-linked inheritance to DKC1.
Telomerase reverse transcriptase (TERT)
TERT hgnc:11730 Autosomal dominant inheritance Autosomal recessive inheritance
DC caused by variants in TERT, the catalytic protein subunit of telomerase. TERT-associated disease can be inherited as autosomal dominant or autosomal recessive and is a common cause of adult-onset/cryptic TBD with pulmonary or hepatic fibrosis.
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"Autosomal dominant or autosomal recessive: ACD, PARN, RTEL1, and TERT."
GeneReviews lists TERT as dominant or recessive DC/TBD.
Telomerase RNA component (TERC)
TERC hgnc:11727 Autosomal dominant inheritance
Autosomal dominant DC caused by variants in TERC, the RNA template subunit of telomerase. Frequently underlies later-onset disease with pulmonary fibrosis.
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"Autosomal dominant: NAF1, RPA1, TERC, TINF2, and ZCCHC8."
GeneReviews lists TERC as autosomal dominant DC/TBD.
Shelterin TINF2 (TIN2)
TINF2 hgnc:11824 Autosomal dominant inheritance
Autosomal dominant DC caused by variants in TINF2 encoding the shelterin component TIN2. TINF2 disease is often severe and early-onset, and is enriched for severe variants including Revesz syndrome and progression to liver disease.
Show evidence (1 reference)
PMID:37184208 SUPPORT Human Clinical
"those with heterozygous TINF2 DC were significantly younger, predominantly male, and more likely to have DC-associated mucocutaneous triad features and severe bone marrow failure"
TINF2 DC patients are younger with severe triad features and bone marrow failure.
Regulator of telomere elongation helicase 1 (RTEL1)
RTEL1 hgnc:15888 Autosomal dominant inheritance Autosomal recessive inheritance
DC caused by variants in RTEL1, a DNA helicase that dismantles telomeric T-loops and supports telomere replication. RTEL1 disease can be autosomal dominant or recessive and includes Hoyeraal-Hreidarsson syndrome.
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"Autosomal dominant or autosomal recessive: ACD, PARN, RTEL1, and TERT."
GeneReviews lists RTEL1 as dominant or recessive DC/TBD.
CST complex CTC1
CTC1 hgnc:26169 Autosomal recessive inheritance
Autosomal recessive DC caused by variants in CTC1, a component of the CTC1-STN1-TEN1 (CST) complex that supports telomere C-strand replication and interacts with DNA polymerase alpha-primase. CTC1 disease overlaps with Coats plus syndrome.
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"Autosomal recessive: CTC1, NHP2, NOP10, POT1, STN1, and WRAP53."
GeneReviews lists CTC1 as autosomal recessive DC/TBD.
Replication protein A1 (RPA1)
RPA1 hgnc:10289 Autosomal dominant inheritance
Autosomal dominant DC caused by variants in RPA1, a single-stranded DNA-binding protein involved in telomere replication.
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"Autosomal dominant: NAF1, RPA1, TERC, TINF2, and ZCCHC8."
GeneReviews lists RPA1 as autosomal dominant DC/TBD.
Shelterin ACD (TPP1)
ACD hgnc:25070 Autosomal dominant inheritance Autosomal recessive inheritance
DC caused by variants in ACD encoding the shelterin protein TPP1, which recruits and stimulates telomerase. ACD disease can be autosomal dominant or recessive.
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"Autosomal dominant or autosomal recessive: ACD, PARN, RTEL1, and TERT."
GeneReviews lists ACD as dominant or recessive DC/TBD.
H/ACA snoRNP NHP2
NHP2 hgnc:14377 Autosomal recessive inheritance
Autosomal recessive DC caused by variants in NHP2, an H/ACA ribonucleoprotein component required for telomerase RNA stability.
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"Autosomal recessive: CTC1, NHP2, NOP10, POT1, STN1, and WRAP53."
GeneReviews lists NHP2 as autosomal recessive DC/TBD.
H/ACA snoRNP NOP10
NOP10 hgnc:14378 Autosomal recessive inheritance
Autosomal recessive DC caused by variants in NOP10, an H/ACA ribonucleoprotein component required for telomerase RNA stability.
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"Autosomal recessive: CTC1, NHP2, NOP10, POT1, STN1, and WRAP53."
GeneReviews lists NOP10 as autosomal recessive DC/TBD.
Poly(A)-specific ribonuclease (PARN)
PARN hgnc:8609 Autosomal dominant inheritance Autosomal recessive inheritance
DC caused by variants in PARN, a deadenylase required for maturation of the telomerase RNA component (TERC). PARN disease can be autosomal dominant or recessive and is associated with pulmonary fibrosis.
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"Autosomal dominant or autosomal recessive: ACD, PARN, RTEL1, and TERT."
GeneReviews lists PARN as dominant or recessive DC/TBD.
WRAP53 (TCAB1)
WRAP53 hgnc:25522 Autosomal recessive inheritance
Autosomal recessive DC caused by variants in WRAP53 (TCAB1), which traffics telomerase to Cajal bodies for recruitment to telomeres.
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"Autosomal recessive: CTC1, NHP2, NOP10, POT1, STN1, and WRAP53."
GeneReviews lists WRAP53 as autosomal recessive DC/TBD.
Shelterin POT1
POT1 hgnc:17284 Autosomal recessive inheritance
Autosomal recessive DC caused by variants in POT1, a shelterin component that binds telomeric single-stranded DNA. Novel POT1 variants expanding the DC allelic series reduce binding to telomeric ssDNA.
Show evidence (1 reference)
PMID:39198715 SUPPORT Human Clinical
"we have also identified several novel variants in POT1 and ZCCHC8 in multiple cases from different families expanding the allelic series of DC and DCL phenotypes."
Novel POT1 variants expand the DC allelic series.
Nuclear assembly factor 1 (NAF1)
NAF1 hgnc:25126 Autosomal dominant inheritance
Autosomal dominant DC/TBD caused by variants in NAF1, an H/ACA ribonucleoprotein assembly factor required for biogenesis and stability of the telomerase RNA component.
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"Autosomal dominant: NAF1, RPA1, TERC, TINF2, and ZCCHC8."
GeneReviews lists NAF1 as autosomal dominant DC/TBD.
CST complex STN1
STN1 hgnc:26200 Autosomal recessive inheritance
Autosomal recessive DC/TBD caused by variants in STN1, a component of the CST (CTC1-STN1-TEN1) complex that supports telomere replication and C-strand fill-in.
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"Autosomal recessive: CTC1, NHP2, NOP10, POT1, STN1, and WRAP53."
GeneReviews lists STN1 as autosomal recessive DC/TBD.
ZCCHC8 (nuclear exosome targeting complex)
ZCCHC8 hgnc:25265 Autosomal dominant inheritance
Autosomal dominant DC/TBD caused by variants in ZCCHC8, a component of the nuclear exosome targeting (NEXT) complex involved in processing/quality control of the telomerase RNA component.
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"Autosomal dominant: NAF1, RPA1, TERC, TINF2, and ZCCHC8."
GeneReviews lists ZCCHC8 as autosomal dominant DC/TBD.
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Discussions and Knowledge Gaps

1
What accounts for the roughly 20% of clinically diagnosed dyskeratosis congenita / telomere biology disorder cases in which no pathogenic variant is identified in any of the 16 known DC/TBD genes?
KNOWLEDGE GAP OPEN gap_dc_unexplained_genetic_cause
GeneReviews reports that pathogenic variants in the 16 known DC/TBD genes are identified in approximately 80% of individuals meeting clinical diagnostic criteria, leaving roughly one in five clinically diagnosed patients genetically unexplained. These cases likely harbor variants in undiscovered genes, non-coding or structural variants in known loci, or somatic/mosaic events not captured by standard testing. Resolving this gap would extend the mechanistic chain (impaired telomere maintenance) to currently uncharacterized molecular causes and improve molecular diagnosis and counseling.
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"in approximately 80% of individuals who meet"
GeneReviews reports a genetic diagnostic yield of approximately 80%, implying roughly 20% of clinically diagnosed DC/TBD remains genetically unexplained.

Pathophysiology

3
Impaired Telomere Maintenance
The unifying upstream defect in DC is impaired telomere maintenance. Germline pathogenic variants in genes encoding telomerase (TERT catalytic subunit, TERC RNA template), the H/ACA snoRNP that stabilizes TERC (DKC1/dyskerin, NHP2, NOP10, NAF1), telomerase trafficking factors (WRAP53/TCAB1), the shelterin complex (TINF2, ACD/TPP1, POT1), the CST replication complex (CTC1, STN1, RPA1), and the RTEL1 helicase reduce the cell's ability to replenish telomeric repeats. Telomeres are nucleoprotein caps that prevent activation of the DNA damage response at chromosome ends.
Hematopoietic stem cell CL:0000037
Telomere maintenance GO:0000723 ↓ DECREASED Telomere maintenance via telomerase GO:0007004 ↓ DECREASED
Telomerase RNA binding GO:0070034
Telomerase holoenzyme complex GO:0005697
Show evidence (2 references)
PMID:20301779 SUPPORT Human Clinical
"Dyskeratosis congenita and related telomere biology disorders (DC/TBD) are caused by impaired telomere maintenance resulting in short or very short telomeres."
Establishes impaired telomere maintenance as the unifying cause of DC.
PMID:36151328 SUPPORT Human Clinical
"Mendelian defects in several of these factors can result in abnormally short or dysfunctional telomeres"
Mendelian defects in telomere factors produce short or dysfunctional telomeres.
Critically Short Telomeres and Replicative Senescence
Defective maintenance leads to progressive telomere attrition until telomeres become critically short or dysfunctional. Critically short telomeres are sensed as DNA damage, activating the p53/p21 DNA damage response and driving affected cells into replicative senescence or apoptosis, thereby limiting the replicative capacity of the tissue. Very short telomeres (often below the 1st percentile for age) are the diagnostic hallmark of DC.
Hematopoietic stem cell CL:0000037
Replicative senescence GO:0090399 ↑ INCREASED Apoptotic process GO:0006915 ↑ INCREASED p53-mediated DNA damage response GO:0030330 ↑ INCREASED
Show evidence (2 references)
PMID:39371255 SUPPORT Human Clinical
"telomeres shorten continuously with each cell division until critically short telomeres prevent further proliferation whereby cells undergo terminal differentiation, senescence, or apoptosis."
Critically short telomeres halt proliferation and trigger senescence or apoptosis.
PMID:40215293 SUPPORT Model Organism
"Molecular analyses revealed a reduction of proliferating cells, increased apoptosis, and stem cell depletion with activation of the p53/p21 signaling pathway."
Ten1-knockout mouse model demonstrates p53/p21 activation, apoptosis, and stem cell depletion from telomere dysfunction.
Stem Cell Exhaustion in High-Turnover Tissues
Because telomere reserve restricts replicative capacity, tissues with high proliferative demand are preferentially affected. Premature replicative exhaustion of stem and progenitor cells in the bone marrow, immune system, skin and mucosa, liver, and lung produces the characteristic multisystem phenotype: bone marrow failure, mucocutaneous changes, and hepatic and pulmonary fibrosis. Genomic instability from dysfunctional telomeres also underlies the predisposition to myelodysplastic syndrome, leukemia, and squamous cell carcinoma.
Hematopoietic stem cell CL:0000037 Hematopoietic precursor cell CL:0008001 Pulmonary alveolar type 2 cell CL:0002063
Show evidence (1 reference)
PMID:39371255 SUPPORT Human Clinical
"altered telomere maintenance as observed in TBDs typically results in premature replicative cellular exhaustion in the respective organ systems eventually leading to life-threatening complications such as bone marrow failure (BMF), pulmonary fibrosis, and liver cirrhosis."
Premature replicative exhaustion in high-turnover organs causes bone marrow failure, pulmonary fibrosis, and liver cirrhosis.

Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.
Pathograph: causal mechanism network for Dyskeratosis Congenita Interactive directed graph showing how pathophysiology mechanisms, phenotypes, genetic factors and variants, experimental models, environmental triggers, and treatments relate through causal and linked edges.

Phenotypes

12
Blood 1
Predisposition to myelodysplastic syndrome and acute myeloid leukemia Myelodysplasia HP:0002863
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"increased risk for progressive bone marrow failure (BMF), myelodysplastic syndrome or acute myelogenous leukemia"
DC predisposes to myelodysplastic syndrome and acute myeloid leukemia.
Immune 1
Immunodeficiency Immunodeficiency HP:0002721
Show evidence (1 reference)
PMID:39371255 SUPPORT Human Clinical
"a sufficient telomere reserve is particularly important in cells with high proliferative activity (e.g., hematopoiesis, immune cells, intestinal cells, liver, lung, and skin)."
Immune cells require telomere reserve; telomere depletion compromises immune function.
Integument 2
Nail dystrophy VERY_FREQUENT Nail dystrophy HP:0008404
Show evidence (2 references)
PMID:20301779 SUPPORT Human Clinical
"Classic DC is characterized by a triad of dysplastic nails, lacy reticular pigmentation of the upper chest and/or neck, and oral leukoplakia"
Dysplastic nails are part of the diagnostic DC triad.
ORPHA:1775 SUPPORT
"HP:0008404 | Nail dystrophy | Very frequent (99-80%)"
Orphanet classifies nail dystrophy as very frequent in dyskeratosis congenita.
Predisposition to squamous cell carcinoma Squamous cell carcinoma HP:0002860
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"solid tumors (usually squamous cell carcinoma of the head/neck or anogenital cancer)"
DC predisposes to squamous cell carcinoma of the head/neck or anogenital region.
Nervous System 1
Cerebellar hypoplasia (Hoyeraal-Hreidarsson syndrome) Cerebellar hypoplasia HP:0001321
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"additional findings include cerebellar hypoplasia (Hoyeraal Hreidarsson syndrome)"
Cerebellar hypoplasia defines the Hoyeraal-Hreidarsson severe DC variant.
Respiratory 1
Pulmonary fibrosis Pulmonary fibrosis HP:0002206
Show evidence (2 references)
PMID:20301779 SUPPORT Human Clinical
"increased risk for progressive bone marrow failure (BMF), myelodysplastic syndrome or acute myelogenous leukemia, solid tumors (usually squamous cell carcinoma of the head/neck or anogenital cancer), and pulmonary fibrosis."
Pulmonary fibrosis is a recognized DC complication.
PMID:34479523 SUPPORT Human Clinical
"PF caused by DC should be kept in mind by clinicians in the differential diagnosis of patients with unexplained PF and should be excluded before diagnostic surgical lung biopsy is undertaken or empirical immunosuppression therapy is prescribed."
DC-associated pulmonary fibrosis should be excluded before lung biopsy or immunosuppression.
Other 6
Reticular skin pigmentation Reticulated skin pigmentation HP:0007427
Show evidence (2 references)
PMID:20301779 SUPPORT Human Clinical
"a triad of dysplastic nails, lacy reticular pigmentation of the upper chest and/or neck, and oral leukoplakia"
Lacy reticular pigmentation is part of the diagnostic DC triad.
ORPHA:1775 SUPPORT
"classic triad of nail dysplasia, skin pigmentary changes, and oral leukoplakia"
Orphanet's definition supports pigmentary skin change as part of the classic DC triad.
Oral leukoplakia VERY_FREQUENT Oral leukoplakia HP:0002745
Show evidence (2 references)
PMID:20301779 SUPPORT Human Clinical
"a triad of dysplastic nails, lacy reticular pigmentation of the upper chest and/or neck, and oral leukoplakia"
Oral leukoplakia is part of the diagnostic DC triad.
ORPHA:1775 SUPPORT
"HP:0002745 | Oral leukoplakia | Very frequent (99-80%)"
Orphanet classifies oral leukoplakia as very frequent in dyskeratosis congenita.
Bone marrow failure Aplastic anemia HP:0001915
Course: PROGRESSIVE
Show evidence (2 references)
PMID:20301779 SUPPORT Human Clinical
"People with DC/TBD are at increased risk for progressive bone marrow failure (BMF)"
Progressive bone marrow failure is a defining complication of DC.
PMID:37593443 SUPPORT Human Clinical
"Thirteen progressed to bone marrow failure at a median age of 8 years"
13/14 children progressed to bone marrow failure at median age 8 years.
Bone marrow hypocellularity Bone marrow hypocellularity HP:0005528
Show evidence (2 references)
PMID:39371255 SUPPORT Human Clinical
"altered telomere maintenance as observed in TBDs typically results in premature replicative cellular exhaustion in the respective organ systems eventually leading to life-threatening complications such as bone marrow failure (BMF)"
Replicative exhaustion of marrow precursors leads to bone marrow failure and hypocellularity.
ORPHA:1775 SUPPORT
"HP:0005528 | Bone marrow hypocellularity | Frequent (79-30%)"
Orphanet classifies bone marrow hypocellularity as frequent in dyskeratosis congenita.
Hepatic fibrosis and portal hypertension Periportal fibrosis HP:0001405
Show evidence (2 references)
PMID:37184208 SUPPORT Human Clinical
"Liver abnormality (defined at baseline assessment by laboratory and/or radiological findings) was present in 72.4% of patients with predominantly cholestatic pattern of liver enzyme elevation."
Liver abnormality was present in 72.4% of DC/TBD patients with cholestatic pattern.
PMID:37184208 SUPPORT Human Clinical
"Clinically significant liver disease and portal hypertension developed in 17.2% of patients during the 6-year follow-up; this progression was mainly seen in patients with recessive or TINF2 -associated DC."
17.2% progressed to clinically significant liver disease and portal hypertension.
Exudative retinopathy (Revesz syndrome) Exudative vitreoretinopathy HP:0030490
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"bilateral exudative retinopathy and intracranial calcifications (Revesz syndrome"
Bilateral exudative retinopathy defines the Revesz severe DC variant.
🧬

Genetic Associations

17
DKC1
Gene: DKC1 hgnc:2890 relationship_type: CAUSATIVE variant_origin: GERMLINE
X-linked recessive inheritance
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"ACD, CTC1, DKC1, NAF1, NHP2, NOP10, PARN, POT1, RPA1, RTEL1, STN1, TERC, TERT, TINF2, WRAP53, and ZCCHC8 are the genes in which pathogenic variants are known to cause DC/TBD"
GeneReviews lists DKC1 among the 16 genes causing DC/TBD.
TERT
Gene: TERT hgnc:11730 relationship_type: CAUSATIVE variant_origin: GERMLINE
Autosomal dominant inheritance Autosomal recessive inheritance
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"ACD, CTC1, DKC1, NAF1, NHP2, NOP10, PARN, POT1, RPA1, RTEL1, STN1, TERC, TERT, TINF2, WRAP53, and ZCCHC8 are the genes in which pathogenic variants are known to cause DC/TBD"
GeneReviews lists TERT among the 16 genes causing DC/TBD.
TERC
Gene: TERC hgnc:11727 relationship_type: CAUSATIVE variant_origin: GERMLINE
Autosomal dominant inheritance
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"ACD, CTC1, DKC1, NAF1, NHP2, NOP10, PARN, POT1, RPA1, RTEL1, STN1, TERC, TERT, TINF2, WRAP53, and ZCCHC8 are the genes in which pathogenic variants are known to cause DC/TBD"
GeneReviews lists TERC among the 16 genes causing DC/TBD.
TINF2
Gene: TINF2 hgnc:11824 relationship_type: CAUSATIVE variant_origin: GERMLINE
Autosomal dominant inheritance
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"ACD, CTC1, DKC1, NAF1, NHP2, NOP10, PARN, POT1, RPA1, RTEL1, STN1, TERC, TERT, TINF2, WRAP53, and ZCCHC8 are the genes in which pathogenic variants are known to cause DC/TBD"
GeneReviews lists TINF2 among the 16 genes causing DC/TBD.
RTEL1
Gene: RTEL1 hgnc:15888 relationship_type: CAUSATIVE variant_origin: GERMLINE
Autosomal dominant inheritance Autosomal recessive inheritance
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"ACD, CTC1, DKC1, NAF1, NHP2, NOP10, PARN, POT1, RPA1, RTEL1, STN1, TERC, TERT, TINF2, WRAP53, and ZCCHC8 are the genes in which pathogenic variants are known to cause DC/TBD"
GeneReviews lists RTEL1 among the 16 genes causing DC/TBD.
CTC1
Gene: CTC1 hgnc:26169 relationship_type: CAUSATIVE variant_origin: GERMLINE
Autosomal recessive inheritance
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"ACD, CTC1, DKC1, NAF1, NHP2, NOP10, PARN, POT1, RPA1, RTEL1, STN1, TERC, TERT, TINF2, WRAP53, and ZCCHC8 are the genes in which pathogenic variants are known to cause DC/TBD"
GeneReviews lists CTC1 among the 16 genes causing DC/TBD.
RPA1
Gene: RPA1 hgnc:10289 relationship_type: CAUSATIVE variant_origin: GERMLINE
Autosomal dominant inheritance
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"ACD, CTC1, DKC1, NAF1, NHP2, NOP10, PARN, POT1, RPA1, RTEL1, STN1, TERC, TERT, TINF2, WRAP53, and ZCCHC8 are the genes in which pathogenic variants are known to cause DC/TBD"
GeneReviews lists RPA1 among the 16 genes causing DC/TBD.
ACD
Gene: ACD hgnc:25070 relationship_type: CAUSATIVE variant_origin: GERMLINE
Autosomal dominant inheritance Autosomal recessive inheritance
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"ACD, CTC1, DKC1, NAF1, NHP2, NOP10, PARN, POT1, RPA1, RTEL1, STN1, TERC, TERT, TINF2, WRAP53, and ZCCHC8 are the genes in which pathogenic variants are known to cause DC/TBD"
GeneReviews lists ACD among the 16 genes causing DC/TBD.
NHP2
Gene: NHP2 hgnc:14377 relationship_type: CAUSATIVE variant_origin: GERMLINE
Autosomal recessive inheritance
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"ACD, CTC1, DKC1, NAF1, NHP2, NOP10, PARN, POT1, RPA1, RTEL1, STN1, TERC, TERT, TINF2, WRAP53, and ZCCHC8 are the genes in which pathogenic variants are known to cause DC/TBD"
GeneReviews lists NHP2 among the 16 genes causing DC/TBD.
NOP10
Gene: NOP10 hgnc:14378 relationship_type: CAUSATIVE variant_origin: GERMLINE
Autosomal recessive inheritance
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"ACD, CTC1, DKC1, NAF1, NHP2, NOP10, PARN, POT1, RPA1, RTEL1, STN1, TERC, TERT, TINF2, WRAP53, and ZCCHC8 are the genes in which pathogenic variants are known to cause DC/TBD"
GeneReviews lists NOP10 among the 16 genes causing DC/TBD.
PARN
Gene: PARN hgnc:8609 relationship_type: CAUSATIVE variant_origin: GERMLINE
Autosomal dominant inheritance Autosomal recessive inheritance
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"ACD, CTC1, DKC1, NAF1, NHP2, NOP10, PARN, POT1, RPA1, RTEL1, STN1, TERC, TERT, TINF2, WRAP53, and ZCCHC8 are the genes in which pathogenic variants are known to cause DC/TBD"
GeneReviews lists PARN among the 16 genes causing DC/TBD.
WRAP53
Gene: WRAP53 hgnc:25522 relationship_type: CAUSATIVE variant_origin: GERMLINE
Autosomal recessive inheritance
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"ACD, CTC1, DKC1, NAF1, NHP2, NOP10, PARN, POT1, RPA1, RTEL1, STN1, TERC, TERT, TINF2, WRAP53, and ZCCHC8 are the genes in which pathogenic variants are known to cause DC/TBD"
GeneReviews lists WRAP53 among the 16 genes causing DC/TBD.
POT1
Gene: POT1 hgnc:17284 relationship_type: CAUSATIVE variant_origin: GERMLINE
Autosomal recessive inheritance
Show evidence (1 reference)
PMID:39198715 SUPPORT Human Clinical
"we have also identified several novel variants in POT1 and ZCCHC8 in multiple cases from different families expanding the allelic series of DC and DCL phenotypes."
Novel POT1 variants expand the DC allelic series.
POLA1
Gene: POLA1 hgnc:9173 relationship_type: CAUSATIVE variant_origin: GERMLINE
X-linked recessive inheritance
Show evidence (2 references)
PMID:39198715 SUPPORT Human Clinical
"This led us to identify several novel pathogenic variants within known genetic loci and in the novel X-linked gene, POLA1."
POLA1 is a newly identified X-linked DC gene.
PMID:39198715 SUPPORT In Vitro
"Functional characterisation of novel POLA1 and POT1 variants, revealed pathogenic effects on protein-protein interactions with primase, CTC1-STN1-TEN1 (CST) and shelterin subunit complexes, that are critical for telomere maintenance."
Functional studies show POLA1 variants disrupt CST/shelterin/primase interactions required for telomere maintenance.
NAF1
Gene: NAF1 hgnc:25126 relationship_type: CAUSATIVE variant_origin: GERMLINE
Autosomal dominant inheritance
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"ACD, CTC1, DKC1, NAF1, NHP2, NOP10, PARN, POT1, RPA1, RTEL1, STN1, TERC, TERT, TINF2, WRAP53, and ZCCHC8 are the genes in which pathogenic variants are known to cause DC/TBD"
GeneReviews lists NAF1 among the 16 genes causing DC/TBD.
STN1
Gene: STN1 hgnc:26200 relationship_type: CAUSATIVE variant_origin: GERMLINE
Autosomal recessive inheritance
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"ACD, CTC1, DKC1, NAF1, NHP2, NOP10, PARN, POT1, RPA1, RTEL1, STN1, TERC, TERT, TINF2, WRAP53, and ZCCHC8 are the genes in which pathogenic variants are known to cause DC/TBD"
GeneReviews lists STN1 among the 16 genes causing DC/TBD.
ZCCHC8
Gene: ZCCHC8 hgnc:25265 relationship_type: CAUSATIVE variant_origin: GERMLINE
Autosomal dominant inheritance
Show evidence (2 references)
PMID:20301779 SUPPORT Human Clinical
"ACD, CTC1, DKC1, NAF1, NHP2, NOP10, PARN, POT1, RPA1, RTEL1, STN1, TERC, TERT, TINF2, WRAP53, and ZCCHC8 are the genes in which pathogenic variants are known to cause DC/TBD"
GeneReviews lists ZCCHC8 among the 16 genes causing DC/TBD.
PMID:39198715 SUPPORT Human Clinical
"we have also identified several novel variants in POT1 and ZCCHC8 in multiple cases from different families expanding the allelic series of DC and DCL phenotypes."
Novel ZCCHC8 variants expand the DC allelic series.
💊

Medical Actions

5
Hematopoietic stem cell transplantation
Action: hematopoietic stem cell transplantation MAXO:0000747
Hematopoietic cell transplantation is the only curative treatment for bone marrow failure and leukemia in DC, but historically has poor long-term outcome due to treatment toxicity. Radiation- and alkylator-reduced conditioning is favored, and related donors carrying the familial variant should be avoided.
Mechanism Target:
MODULATES Stem Cell Exhaustion in High-Turnover Tissues — HSCT replaces the dysfunctional short-telomere hematopoietic stem cell pool with donor-derived cells, rescuing hematopoiesis and reducing leukemia risk; it does not correct the underlying telomere maintenance defect in non-hematopoietic tissues.
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"Hematopoietic cell transplantation (HCT) is the only curative treatment for BMF and leukemia, but long-term outcome has historically been poor due to treatment toxicity"
HCT is the only curative treatment for DC marrow failure/leukemia but is toxicity-limited.
Androgen therapy (danazol)
Action: Pharmacotherapy NCIT:C15986
Agent: danazol CHEBI:4315 oxymetholone CHEBI:7864
Androgen therapy (e.g., danazol, oxymetholone) can improve blood counts and may be considered for bone marrow failure when a suitable transplant donor is not available. The combination of androgens with granulocyte colony-stimulating factor should be avoided because it has been associated with splenic rupture; monitoring of CBC, liver function, and liver ultrasound is recommended.
Mechanism Target:
MODULATES Impaired Telomere Maintenance — Androgens (danazol, oxymetholone) upregulate TERT expression, boosting telomerase activity in hematopoietic progenitors and partially reversing the telomere maintenance defect.
MODULATES Critically Short Telomeres and Replicative Senescence — By stimulating TERT, androgen therapy can slow the rate of telomere attrition in bone marrow progenitors, delaying progression to replicative senescence and improving blood counts.
Show evidence (2 references)
PMID:20301779 SUPPORT Human Clinical
"if a suitable donor is not available, androgen therapy may be considered for BMF."
Androgen therapy is an option for bone marrow failure when transplant is not available.
PMID:20301779 SUPPORT Human Clinical
"the combination of androgens and granulocyte colony-stimulating factor in treatment of BMF (has been associated with splenic rupture)"
GeneReviews Agents/Circumstances to Avoid - androgen plus G-CSF risks splenic rupture.
Lung transplantation
Action: organ transplantation MAXO:0010039
Treatment of pulmonary fibrosis is primarily supportive, although lung transplantation may be considered for end-stage disease.
Mechanism Target:
MODULATES Stem Cell Exhaustion in High-Turnover Tissues — Lung transplantation replaces end-stage fibrotic lung tissue; it does not address the underlying telomere biology defect and DC patients face elevated post-transplant risks from impaired regenerative capacity in other high-turnover tissues.
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"Treatment of pulmonary fibrosis is primarily supportive, although lung transplantation may be considered."
Lung transplantation may be considered for DC-associated pulmonary fibrosis.
Cancer surveillance and supportive care
Action: supportive care MAXO:0000950
Surveillance is central to DC management, including annual CBC and bone marrow evaluation, monthly oral/head/neck self-examination with annual otolaryngology and dermatology screening, and annual pulmonary function tests. Of note, cancer therapy may pose an increased risk of prolonged cytopenias and pulmonary and hepatic toxicity, and non-irradiated/leukodepleted blood products should be used.
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"cancer therapy may pose an increased risk for prolonged cytopenias as well as pulmonary and hepatic toxicity."
GeneReviews notes increased risk from cancer therapy, motivating surveillance and supportive care.
Genetic counseling
Action: Genetic Counseling NCIT:C15240
Genetic counseling addresses gene-specific mode of inheritance; once the familial variant is identified, prenatal and preimplantation genetic testing are possible. Family members should not donate blood if HCT is being considered, and potential related donors require telomere length and/or molecular testing.
Show evidence (1 reference)
PMID:20301779 SUPPORT Human Clinical
"Once the DC/TBD-related pathogenic variant(s) have been identified in an affected family member, prenatal and preimplantation genetic testing are possible."
Genetic counseling enables prenatal/preimplantation testing once the variant is known.
{ }

Source YAML

click to show
name: Dyskeratosis Congenita
creation_date: "2026-06-05T12:00:00Z"
category: Mendelian
description: >-
  Dyskeratosis congenita (DC) is a rare inherited multisystem telomere biology
  disorder (TBD) caused by impaired telomere maintenance resulting in abnormally
  short or dysfunctional telomeres. Classic DC is defined by a mucocutaneous triad
  of dysplastic nails, lacy reticular skin pigmentation, and oral leukoplakia, and
  is complicated by progressive bone marrow failure, predisposition to
  myelodysplastic syndrome / acute myeloid leukemia and squamous cell carcinoma,
  and pulmonary and hepatic fibrosis. DC sits at the early-onset, classic end of
  the broader telomere biology disorder spectrum, with Hoyeraal-Hreidarsson
  syndrome (with cerebellar hypoplasia) and Revesz syndrome (with exudative
  retinopathy) representing severe variants. Pathogenic germline variants in at
  least 16 genes spanning the telomerase core (TERT, TERC), the H/ACA snoRNP
  (DKC1, NHP2, NOP10, NAF1), telomerase trafficking (WRAP53), the shelterin
  complex (TINF2, ACD, POT1), the CST replication complex (CTC1, STN1, RPA1), the
  RTEL1 helicase, and RNA-processing factors (PARN, ZCCHC8) cause DC, with
  X-linked, autosomal dominant, and autosomal recessive inheritance depending on
  the gene. Diagnosis relies on multicolor flow-FISH lymphocyte telomere length
  testing (very short telomeres, often below the 1st percentile for age) and
  germline genetic testing, which identifies a pathogenic variant in approximately
  80% of clinically diagnosed individuals.
disease_term:
  preferred_term: Dyskeratosis Congenita
  term:
    id: MONDO:0015780
    label: dyskeratosis congenita
parents:
- Bone Marrow Failure
- Inherited Bone Marrow Failure Syndrome
- Telomere Biology Disorder

references:
- reference: PMID:20301779
  title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
  tags:
  - GeneReviews

inheritance:
- name: X-linked recessive inheritance
  inheritance_term:
    preferred_term: X-linked recessive inheritance
    term:
      id: HP:0001419
      label: X-linked recessive inheritance
  description: >-
    X-linked recessive inheritance applies to DKC1, the gene encoding dyskerin and
    historically the most common and most severe form of classic DC.
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The mode of inheritance of DC/TBD varies by gene: X-linked: DKC1."
    explanation: GeneReviews assigns X-linked inheritance specifically to DKC1.
- name: Autosomal dominant inheritance
  inheritance_term:
    preferred_term: Autosomal dominant inheritance
    term:
      id: HP:0000006
      label: Autosomal dominant inheritance
  description: >-
    Autosomal dominant inheritance applies to NAF1, RPA1, TERC, TINF2, and ZCCHC8,
    and is the most frequent mode in adult-onset (cryptic) TBD.
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Autosomal dominant: NAF1, RPA1, TERC, TINF2, and ZCCHC8."
    explanation: GeneReviews lists the autosomal dominant DC/TBD genes.
  - reference: PMID:38066848
    reference_title: "Clinical manifestations of telomere biology disorders in adults."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "TBD genetic etiology includes all modes of inheritance, with autosomal dominant the most frequent in adult-onset disease."
    explanation: Autosomal dominant inheritance predominates in adult-onset TBD.
- name: Autosomal recessive inheritance
  inheritance_term:
    preferred_term: Autosomal recessive inheritance
    term:
      id: HP:0000007
      label: Autosomal recessive inheritance
  description: >-
    Autosomal recessive inheritance applies to CTC1, NHP2, NOP10, POT1, STN1, and
    WRAP53; ACD, PARN, RTEL1, and TERT can be inherited as either dominant or
    recessive.
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Autosomal recessive: CTC1, NHP2, NOP10, POT1, STN1, and WRAP53."
    explanation: GeneReviews lists the autosomal recessive DC/TBD genes.

prevalence:
- population: Global
  prevalence_class: RARE
  percentage: Rare
  notes: >-
    DC is consistently described as an ultra-rare/rare inherited bone marrow
    failure syndrome. Reported prevalence estimates range from approximately 1 per
    1,000,000 to 1-9 per 1,000,000.
  evidence:
  - reference: PMID:37593443
    reference_title: "Dyskeratosis congenita: natural history of the disease through the study of a cohort of patients diagnosed in childhood."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Dyskeratosis congenita (DC) is a multisystem and ultra-rare hereditary disease characterized by somatic involvement, bone marrow failure, and predisposition to cancer."
    explanation: Characterizes DC as an ultra-rare hereditary multisystem disease.

progression:
- phase: Onset
  age_range: Childhood
  notes: >-
    Classic DC typically presents in childhood with mucocutaneous features and
    early bone marrow failure, whereas cryptic/adult-onset TBD may present in mid-
    or late adulthood with isolated pulmonary, hepatic, hematologic disease, or
    cancer.
  evidence:
  - reference: PMID:37593443
    reference_title: "Dyskeratosis congenita: natural history of the disease through the study of a cohort of patients diagnosed in childhood."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Fourteen patients were diagnosed with DC between the ages of 3 and 17 years (median, 8.5 years). They all had hematologic manifestations at diagnosis"
    explanation: Childhood-diagnosed cohort with median diagnosis age 8.5 years and universal hematologic manifestations.
  - reference: PMID:38066848
    reference_title: "Clinical manifestations of telomere biology disorders in adults."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Adult-onset TBDs are often cryptic with isolated pulmonary, liver, or hematologic disease, or cancer, and may lack the classic disease-defining triad"
    explanation: Adult-onset TBD presents cryptically and may lack the triad.
- phase: Bone marrow failure
  notes: >-
    The majority of children with classic DC progress to bone marrow failure,
    typically in the first or second decade of life.
  evidence:
  - reference: PMID:37593443
    reference_title: "Dyskeratosis congenita: natural history of the disease through the study of a cohort of patients diagnosed in childhood."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Thirteen progressed to bone marrow failure at a median age of 8 years"
    explanation: 13/14 children progressed to bone marrow failure at median age 8 years.

has_subtypes:
- name: DKC1
  display_name: X-linked DC (DKC1, dyskerin)
  description: >-
    X-linked recessive DC caused by pathogenic variants in DKC1 encoding dyskerin,
    a core component of the H/ACA small nucleolar ribonucleoprotein required for
    pseudouridylation and for stability of the telomerase RNA component. DKC1
    disease is historically the most common and most severe classic DC form,
    including Hoyeraal-Hreidarsson syndrome.
  inheritance:
  - name: X-linked recessive inheritance
    inheritance_term:
      preferred_term: X-linked recessive inheritance
      term:
        id: HP:0001419
        label: X-linked recessive inheritance
  genes:
  - preferred_term: DKC1
    term:
      id: hgnc:2890
      label: DKC1
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The mode of inheritance of DC/TBD varies by gene: X-linked: DKC1."
    explanation: GeneReviews assigns X-linked inheritance to DKC1.
- name: TERT
  display_name: Telomerase reverse transcriptase (TERT)
  description: >-
    DC caused by variants in TERT, the catalytic protein subunit of telomerase.
    TERT-associated disease can be inherited as autosomal dominant or autosomal
    recessive and is a common cause of adult-onset/cryptic TBD with pulmonary or
    hepatic fibrosis.
  inheritance:
  - name: Autosomal dominant inheritance
    inheritance_term:
      preferred_term: Autosomal dominant inheritance
      term:
        id: HP:0000006
        label: Autosomal dominant inheritance
  - name: Autosomal recessive inheritance
    inheritance_term:
      preferred_term: Autosomal recessive inheritance
      term:
        id: HP:0000007
        label: Autosomal recessive inheritance
  genes:
  - preferred_term: TERT
    term:
      id: hgnc:11730
      label: TERT
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Autosomal dominant or autosomal recessive: ACD, PARN, RTEL1, and TERT."
    explanation: GeneReviews lists TERT as dominant or recessive DC/TBD.
- name: TERC
  display_name: Telomerase RNA component (TERC)
  description: >-
    Autosomal dominant DC caused by variants in TERC, the RNA template subunit of
    telomerase. Frequently underlies later-onset disease with pulmonary fibrosis.
  inheritance:
  - name: Autosomal dominant inheritance
    inheritance_term:
      preferred_term: Autosomal dominant inheritance
      term:
        id: HP:0000006
        label: Autosomal dominant inheritance
  genes:
  - preferred_term: TERC
    term:
      id: hgnc:11727
      label: TERC
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Autosomal dominant: NAF1, RPA1, TERC, TINF2, and ZCCHC8."
    explanation: GeneReviews lists TERC as autosomal dominant DC/TBD.
- name: TINF2
  display_name: Shelterin TINF2 (TIN2)
  description: >-
    Autosomal dominant DC caused by variants in TINF2 encoding the shelterin
    component TIN2. TINF2 disease is often severe and early-onset, and is enriched
    for severe variants including Revesz syndrome and progression to liver disease.
  inheritance:
  - name: Autosomal dominant inheritance
    inheritance_term:
      preferred_term: Autosomal dominant inheritance
      term:
        id: HP:0000006
        label: Autosomal dominant inheritance
  genes:
  - preferred_term: TINF2
    term:
      id: hgnc:11824
      label: TINF2
  evidence:
  - reference: PMID:37184208
    reference_title: "Progression of liver disease and portal hypertension in dyskeratosis congenita and related telomere biology disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "those with heterozygous TINF2 DC were significantly younger, predominantly male, and more likely to have DC-associated mucocutaneous triad features and severe bone marrow failure"
    explanation: TINF2 DC patients are younger with severe triad features and bone marrow failure.
- name: RTEL1
  display_name: Regulator of telomere elongation helicase 1 (RTEL1)
  description: >-
    DC caused by variants in RTEL1, a DNA helicase that dismantles telomeric
    T-loops and supports telomere replication. RTEL1 disease can be autosomal
    dominant or recessive and includes Hoyeraal-Hreidarsson syndrome.
  inheritance:
  - name: Autosomal dominant inheritance
    inheritance_term:
      preferred_term: Autosomal dominant inheritance
      term:
        id: HP:0000006
        label: Autosomal dominant inheritance
  - name: Autosomal recessive inheritance
    inheritance_term:
      preferred_term: Autosomal recessive inheritance
      term:
        id: HP:0000007
        label: Autosomal recessive inheritance
  genes:
  - preferred_term: RTEL1
    term:
      id: hgnc:15888
      label: RTEL1
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Autosomal dominant or autosomal recessive: ACD, PARN, RTEL1, and TERT."
    explanation: GeneReviews lists RTEL1 as dominant or recessive DC/TBD.
- name: CTC1
  display_name: CST complex CTC1
  description: >-
    Autosomal recessive DC caused by variants in CTC1, a component of the
    CTC1-STN1-TEN1 (CST) complex that supports telomere C-strand replication and
    interacts with DNA polymerase alpha-primase. CTC1 disease overlaps with Coats
    plus syndrome.
  inheritance:
  - name: Autosomal recessive inheritance
    inheritance_term:
      preferred_term: Autosomal recessive inheritance
      term:
        id: HP:0000007
        label: Autosomal recessive inheritance
  genes:
  - preferred_term: CTC1
    term:
      id: hgnc:26169
      label: CTC1
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Autosomal recessive: CTC1, NHP2, NOP10, POT1, STN1, and WRAP53."
    explanation: GeneReviews lists CTC1 as autosomal recessive DC/TBD.
- name: RPA1
  display_name: Replication protein A1 (RPA1)
  description: >-
    Autosomal dominant DC caused by variants in RPA1, a single-stranded
    DNA-binding protein involved in telomere replication.
  inheritance:
  - name: Autosomal dominant inheritance
    inheritance_term:
      preferred_term: Autosomal dominant inheritance
      term:
        id: HP:0000006
        label: Autosomal dominant inheritance
  genes:
  - preferred_term: RPA1
    term:
      id: hgnc:10289
      label: RPA1
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Autosomal dominant: NAF1, RPA1, TERC, TINF2, and ZCCHC8."
    explanation: GeneReviews lists RPA1 as autosomal dominant DC/TBD.
- name: ACD
  display_name: Shelterin ACD (TPP1)
  description: >-
    DC caused by variants in ACD encoding the shelterin protein TPP1, which
    recruits and stimulates telomerase. ACD disease can be autosomal dominant or
    recessive.
  inheritance:
  - name: Autosomal dominant inheritance
    inheritance_term:
      preferred_term: Autosomal dominant inheritance
      term:
        id: HP:0000006
        label: Autosomal dominant inheritance
  - name: Autosomal recessive inheritance
    inheritance_term:
      preferred_term: Autosomal recessive inheritance
      term:
        id: HP:0000007
        label: Autosomal recessive inheritance
  genes:
  - preferred_term: ACD
    term:
      id: hgnc:25070
      label: ACD
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Autosomal dominant or autosomal recessive: ACD, PARN, RTEL1, and TERT."
    explanation: GeneReviews lists ACD as dominant or recessive DC/TBD.
- name: NHP2
  display_name: H/ACA snoRNP NHP2
  description: >-
    Autosomal recessive DC caused by variants in NHP2, an H/ACA
    ribonucleoprotein component required for telomerase RNA stability.
  inheritance:
  - name: Autosomal recessive inheritance
    inheritance_term:
      preferred_term: Autosomal recessive inheritance
      term:
        id: HP:0000007
        label: Autosomal recessive inheritance
  genes:
  - preferred_term: NHP2
    term:
      id: hgnc:14377
      label: NHP2
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Autosomal recessive: CTC1, NHP2, NOP10, POT1, STN1, and WRAP53."
    explanation: GeneReviews lists NHP2 as autosomal recessive DC/TBD.
- name: NOP10
  display_name: H/ACA snoRNP NOP10
  description: >-
    Autosomal recessive DC caused by variants in NOP10, an H/ACA
    ribonucleoprotein component required for telomerase RNA stability.
  inheritance:
  - name: Autosomal recessive inheritance
    inheritance_term:
      preferred_term: Autosomal recessive inheritance
      term:
        id: HP:0000007
        label: Autosomal recessive inheritance
  genes:
  - preferred_term: NOP10
    term:
      id: hgnc:14378
      label: NOP10
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Autosomal recessive: CTC1, NHP2, NOP10, POT1, STN1, and WRAP53."
    explanation: GeneReviews lists NOP10 as autosomal recessive DC/TBD.
- name: PARN
  display_name: Poly(A)-specific ribonuclease (PARN)
  description: >-
    DC caused by variants in PARN, a deadenylase required for maturation of the
    telomerase RNA component (TERC). PARN disease can be autosomal dominant or
    recessive and is associated with pulmonary fibrosis.
  inheritance:
  - name: Autosomal dominant inheritance
    inheritance_term:
      preferred_term: Autosomal dominant inheritance
      term:
        id: HP:0000006
        label: Autosomal dominant inheritance
  - name: Autosomal recessive inheritance
    inheritance_term:
      preferred_term: Autosomal recessive inheritance
      term:
        id: HP:0000007
        label: Autosomal recessive inheritance
  genes:
  - preferred_term: PARN
    term:
      id: hgnc:8609
      label: PARN
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Autosomal dominant or autosomal recessive: ACD, PARN, RTEL1, and TERT."
    explanation: GeneReviews lists PARN as dominant or recessive DC/TBD.
- name: WRAP53
  display_name: WRAP53 (TCAB1)
  description: >-
    Autosomal recessive DC caused by variants in WRAP53 (TCAB1), which traffics
    telomerase to Cajal bodies for recruitment to telomeres.
  inheritance:
  - name: Autosomal recessive inheritance
    inheritance_term:
      preferred_term: Autosomal recessive inheritance
      term:
        id: HP:0000007
        label: Autosomal recessive inheritance
  genes:
  - preferred_term: WRAP53
    term:
      id: hgnc:25522
      label: WRAP53
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Autosomal recessive: CTC1, NHP2, NOP10, POT1, STN1, and WRAP53."
    explanation: GeneReviews lists WRAP53 as autosomal recessive DC/TBD.
- name: POT1
  display_name: Shelterin POT1
  description: >-
    Autosomal recessive DC caused by variants in POT1, a shelterin component that
    binds telomeric single-stranded DNA. Novel POT1 variants expanding the DC
    allelic series reduce binding to telomeric ssDNA.
  inheritance:
  - name: Autosomal recessive inheritance
    inheritance_term:
      preferred_term: Autosomal recessive inheritance
      term:
        id: HP:0000007
        label: Autosomal recessive inheritance
  genes:
  - preferred_term: POT1
    term:
      id: hgnc:17284
      label: POT1
  evidence:
  - reference: PMID:39198715
    reference_title: "The evolving genetic landscape of telomere biology disorder dyskeratosis congenita."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "we have also identified several novel variants in POT1 and ZCCHC8 in multiple cases from different families expanding the allelic series of DC and DCL phenotypes."
    explanation: Novel POT1 variants expand the DC allelic series.
- name: NAF1
  display_name: Nuclear assembly factor 1 (NAF1)
  description: >-
    Autosomal dominant DC/TBD caused by variants in NAF1, an H/ACA
    ribonucleoprotein assembly factor required for biogenesis and stability of the
    telomerase RNA component.
  inheritance:
  - name: Autosomal dominant inheritance
    inheritance_term:
      preferred_term: Autosomal dominant inheritance
      term:
        id: HP:0000006
        label: Autosomal dominant inheritance
  genes:
  - preferred_term: NAF1
    term:
      id: hgnc:25126
      label: NAF1
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Autosomal dominant: NAF1, RPA1, TERC, TINF2, and ZCCHC8."
    explanation: GeneReviews lists NAF1 as autosomal dominant DC/TBD.
- name: STN1
  display_name: CST complex STN1
  description: >-
    Autosomal recessive DC/TBD caused by variants in STN1, a component of the CST
    (CTC1-STN1-TEN1) complex that supports telomere replication and C-strand fill-in.
  inheritance:
  - name: Autosomal recessive inheritance
    inheritance_term:
      preferred_term: Autosomal recessive inheritance
      term:
        id: HP:0000007
        label: Autosomal recessive inheritance
  genes:
  - preferred_term: STN1
    term:
      id: hgnc:26200
      label: STN1
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Autosomal recessive: CTC1, NHP2, NOP10, POT1, STN1, and WRAP53."
    explanation: GeneReviews lists STN1 as autosomal recessive DC/TBD.
- name: ZCCHC8
  display_name: ZCCHC8 (nuclear exosome targeting complex)
  description: >-
    Autosomal dominant DC/TBD caused by variants in ZCCHC8, a component of the
    nuclear exosome targeting (NEXT) complex involved in processing/quality control
    of the telomerase RNA component.
  inheritance:
  - name: Autosomal dominant inheritance
    inheritance_term:
      preferred_term: Autosomal dominant inheritance
      term:
        id: HP:0000006
        label: Autosomal dominant inheritance
  genes:
  - preferred_term: ZCCHC8
    term:
      id: hgnc:25265
      label: ZCCHC8
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Autosomal dominant: NAF1, RPA1, TERC, TINF2, and ZCCHC8."
    explanation: GeneReviews lists ZCCHC8 as autosomal dominant DC/TBD.

pathophysiology:
- name: Impaired Telomere Maintenance
  description: >-
    The unifying upstream defect in DC is impaired telomere maintenance. Germline
    pathogenic variants in genes encoding telomerase (TERT catalytic subunit, TERC
    RNA template), the H/ACA snoRNP that stabilizes TERC (DKC1/dyskerin, NHP2,
    NOP10, NAF1), telomerase trafficking factors (WRAP53/TCAB1), the shelterin
    complex (TINF2, ACD/TPP1, POT1), the CST replication complex (CTC1, STN1, RPA1),
    and the RTEL1 helicase reduce the cell's ability to replenish telomeric repeats.
    Telomeres are nucleoprotein caps that prevent activation of the DNA damage
    response at chromosome ends.
  cell_types:
  - preferred_term: Hematopoietic stem cell
    term:
      id: CL:0000037
      label: hematopoietic stem cell
  biological_processes:
  - preferred_term: Telomere maintenance
    term:
      id: GO:0000723
      label: telomere maintenance
    modifier: DECREASED
  - preferred_term: Telomere maintenance via telomerase
    term:
      id: GO:0007004
      label: telomere maintenance via telomerase
    modifier: DECREASED
  cellular_components:
  - preferred_term: Telomerase holoenzyme complex
    term:
      id: GO:0005697
      label: telomerase holoenzyme complex
  molecular_functions:
  - preferred_term: Telomerase RNA binding
    term:
      id: GO:0070034
      label: telomerase RNA binding
  genes:
  - preferred_term: DKC1
    term:
      id: hgnc:2890
      label: DKC1
  - preferred_term: TERT
    term:
      id: hgnc:11730
      label: TERT
  - preferred_term: TERC
    term:
      id: hgnc:11727
      label: TERC
  - preferred_term: TINF2
    term:
      id: hgnc:11824
      label: TINF2
  - preferred_term: RTEL1
    term:
      id: hgnc:15888
      label: RTEL1
  - preferred_term: CTC1
    term:
      id: hgnc:26169
      label: CTC1
  - preferred_term: RPA1
    term:
      id: hgnc:10289
      label: RPA1
  - preferred_term: ACD
    term:
      id: hgnc:25070
      label: ACD
  - preferred_term: NHP2
    term:
      id: hgnc:14377
      label: NHP2
  - preferred_term: NOP10
    term:
      id: hgnc:14378
      label: NOP10
  - preferred_term: PARN
    term:
      id: hgnc:8609
      label: PARN
  - preferred_term: WRAP53
    term:
      id: hgnc:25522
      label: WRAP53
  - preferred_term: POT1
    term:
      id: hgnc:17284
      label: POT1
  - preferred_term: POLA1
    term:
      id: hgnc:9173
      label: POLA1
  - preferred_term: NAF1
    term:
      id: hgnc:25126
      label: NAF1
  - preferred_term: STN1
    term:
      id: hgnc:26200
      label: STN1
  - preferred_term: ZCCHC8
    term:
      id: hgnc:25265
      label: ZCCHC8
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Dyskeratosis congenita and related telomere biology disorders (DC/TBD) are caused by impaired telomere maintenance resulting in short or very short telomeres."
    explanation: Establishes impaired telomere maintenance as the unifying cause of DC.
  - reference: PMID:36151328
    reference_title: "Genetics of human telomere biology disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Mendelian defects in several of these factors can result in abnormally short or dysfunctional telomeres"
    explanation: Mendelian defects in telomere factors produce short or dysfunctional telomeres.
  downstream:
  - target: Critically Short Telomeres and Replicative Senescence
- name: Critically Short Telomeres and Replicative Senescence
  description: >-
    Defective maintenance leads to progressive telomere attrition until telomeres
    become critically short or dysfunctional. Critically short telomeres are sensed
    as DNA damage, activating the p53/p21 DNA damage response and driving affected
    cells into replicative senescence or apoptosis, thereby limiting the replicative
    capacity of the tissue. Very short telomeres (often below the 1st percentile for
    age) are the diagnostic hallmark of DC.
  cell_types:
  - preferred_term: Hematopoietic stem cell
    term:
      id: CL:0000037
      label: hematopoietic stem cell
  biological_processes:
  - preferred_term: Replicative senescence
    term:
      id: GO:0090399
      label: replicative senescence
    modifier: INCREASED
  - preferred_term: Apoptotic process
    term:
      id: GO:0006915
      label: apoptotic process
    modifier: INCREASED
  - preferred_term: p53-mediated DNA damage response
    term:
      id: GO:0030330
      label: DNA damage response, signal transduction by p53 class mediator
    modifier: INCREASED
  evidence:
  - reference: PMID:39371255
    reference_title: "Inherited Telomere Biology Disorders: Pathophysiology, Clinical Presentation, Diagnostics, and Treatment."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "telomeres shorten continuously with each cell division until critically short telomeres prevent further proliferation whereby cells undergo terminal differentiation, senescence, or apoptosis."
    explanation: Critically short telomeres halt proliferation and trigger senescence or apoptosis.
  - reference: PMID:40215293
    reference_title: "Loss of Ten1 in mice induces telomere shortening and models human dyskeratosis congenita."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "Molecular analyses revealed a reduction of proliferating cells, increased apoptosis, and stem cell depletion with activation of the p53/p21 signaling pathway."
    explanation: Ten1-knockout mouse model demonstrates p53/p21 activation, apoptosis, and stem cell depletion from telomere dysfunction.
  downstream:
  - target: Stem Cell Exhaustion in High-Turnover Tissues
- name: Stem Cell Exhaustion in High-Turnover Tissues
  description: >-
    Because telomere reserve restricts replicative capacity, tissues with high
    proliferative demand are preferentially affected. Premature replicative
    exhaustion of stem and progenitor cells in the bone marrow, immune system,
    skin and mucosa, liver, and lung produces the characteristic multisystem
    phenotype: bone marrow failure, mucocutaneous changes, and hepatic and
    pulmonary fibrosis. Genomic instability from dysfunctional telomeres also
    underlies the predisposition to myelodysplastic syndrome, leukemia, and
    squamous cell carcinoma.
  cell_types:
  - preferred_term: Hematopoietic stem cell
    term:
      id: CL:0000037
      label: hematopoietic stem cell
  - preferred_term: Hematopoietic precursor cell
    term:
      id: CL:0008001
      label: hematopoietic precursor cell
  - preferred_term: Pulmonary alveolar type 2 cell
    term:
      id: CL:0002063
      label: pulmonary alveolar type 2 cell
  evidence:
  - reference: PMID:39371255
    reference_title: "Inherited Telomere Biology Disorders: Pathophysiology, Clinical Presentation, Diagnostics, and Treatment."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "altered telomere maintenance as observed in TBDs typically results in premature replicative cellular exhaustion in the respective organ systems eventually leading to life-threatening complications such as bone marrow failure (BMF), pulmonary fibrosis, and liver cirrhosis."
    explanation: Premature replicative exhaustion in high-turnover organs causes bone marrow failure, pulmonary fibrosis, and liver cirrhosis.
  downstream:
  - target: Bone marrow failure
    description: Exhaustion of hematopoietic stem and progenitor cells produces progressive bone marrow failure.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:39371255
      reference_title: "Inherited Telomere Biology Disorders: Pathophysiology, Clinical Presentation, Diagnostics, and Treatment."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "premature replicative cellular exhaustion in the respective organ systems eventually leading to life-threatening complications such as bone marrow failure (BMF), pulmonary fibrosis, and liver cirrhosis."
      explanation: The review explicitly links premature cellular exhaustion in affected organs to bone marrow failure.
  - target: Pulmonary fibrosis
    description: Exhaustion of proliferative lung epithelial compartments contributes to telomere-biology-disorder pulmonary fibrosis.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:39371255
      reference_title: "Inherited Telomere Biology Disorders: Pathophysiology, Clinical Presentation, Diagnostics, and Treatment."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "premature replicative cellular exhaustion in the respective organ systems eventually leading to life-threatening complications such as bone marrow failure (BMF), pulmonary fibrosis, and liver cirrhosis."
      explanation: The review explicitly links premature cellular exhaustion in affected organs to pulmonary fibrosis.
  - target: Hepatic fibrosis and portal hypertension
    description: Telomere-driven cellular exhaustion in liver tissue predisposes to fibrotic/cirrhotic liver disease.
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    evidence:
    - reference: PMID:39371255
      reference_title: "Inherited Telomere Biology Disorders: Pathophysiology, Clinical Presentation, Diagnostics, and Treatment."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "premature replicative cellular exhaustion in the respective organ systems eventually leading to life-threatening complications such as bone marrow failure (BMF), pulmonary fibrosis, and liver cirrhosis."
      explanation: The review explicitly links premature cellular exhaustion in affected organs to liver cirrhosis, supporting the hepatic fibrosis/cirrhosis branch.

phenotypes:
- category: Integumentary
  name: Nail dystrophy
  description: >-
    Dysplastic, dystrophic nails are a component of the classic DC mucocutaneous
    triad.
  frequency: VERY_FREQUENT
  phenotype_term:
    preferred_term: Nail dystrophy
    term:
      id: HP:0008404
      label: Nail dystrophy
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Classic DC is characterized by a triad of dysplastic nails, lacy reticular pigmentation of the upper chest and/or neck, and oral leukoplakia"
    explanation: Dysplastic nails are part of the diagnostic DC triad.
  - reference: ORPHA:1775
    supports: SUPPORT
    snippet: "HP:0008404 | Nail dystrophy | Very frequent (99-80%)"
    explanation: Orphanet classifies nail dystrophy as very frequent in dyskeratosis congenita.
- category: Integumentary
  name: Reticular skin pigmentation
  description: >-
    Lacy/reticulated abnormal skin pigmentation, typically of the upper chest
    and/or neck, is a component of the classic DC mucocutaneous triad.
  phenotype_term:
    preferred_term: Reticulated skin pigmentation
    term:
      id: HP:0007427
      label: Reticulated skin pigmentation
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "a triad of dysplastic nails, lacy reticular pigmentation of the upper chest and/or neck, and oral leukoplakia"
    explanation: Lacy reticular pigmentation is part of the diagnostic DC triad.
  - reference: ORPHA:1775
    supports: SUPPORT
    snippet: "classic triad of nail dysplasia, skin pigmentary changes, and oral leukoplakia"
    explanation: Orphanet's definition supports pigmentary skin change as part of the classic DC triad.
- category: Oral
  name: Oral leukoplakia
  description: >-
    Oral leukoplakia is a component of the classic DC mucocutaneous triad and a
    site of increased risk for squamous cell carcinoma.
  frequency: VERY_FREQUENT
  phenotype_term:
    preferred_term: Oral leukoplakia
    term:
      id: HP:0002745
      label: Oral leukoplakia
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "a triad of dysplastic nails, lacy reticular pigmentation of the upper chest and/or neck, and oral leukoplakia"
    explanation: Oral leukoplakia is part of the diagnostic DC triad.
  - reference: ORPHA:1775
    supports: SUPPORT
    snippet: "HP:0002745 | Oral leukoplakia | Very frequent (99-80%)"
    explanation: Orphanet classifies oral leukoplakia as very frequent in dyskeratosis congenita.
- category: Hematologic
  name: Bone marrow failure
  description: >-
    Progressive bone marrow failure is a hallmark complication of DC and the
    leading cause of early mortality. Most children with classic DC progress to
    bone marrow failure.
  phenotype_term:
    preferred_term: Aplastic anemia
    term:
      id: HP:0001915
      label: Aplastic anemia
    clinical_course: PROGRESSIVE
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "People with DC/TBD are at increased risk for progressive bone marrow failure (BMF)"
    explanation: Progressive bone marrow failure is a defining complication of DC.
  - reference: PMID:37593443
    reference_title: "Dyskeratosis congenita: natural history of the disease through the study of a cohort of patients diagnosed in childhood."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Thirteen progressed to bone marrow failure at a median age of 8 years"
    explanation: 13/14 children progressed to bone marrow failure at median age 8 years.
- category: Hematologic
  name: Bone marrow hypocellularity
  description: >-
    Bone marrow hypocellularity reflects hematopoietic stem cell exhaustion from
    telomere dysfunction.
  phenotype_term:
    preferred_term: Bone marrow hypocellularity
    term:
      id: HP:0005528
      label: Bone marrow hypocellularity
  evidence:
  - reference: PMID:39371255
    reference_title: "Inherited Telomere Biology Disorders: Pathophysiology, Clinical Presentation, Diagnostics, and Treatment."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "altered telomere maintenance as observed in TBDs typically results in premature replicative cellular exhaustion in the respective organ systems eventually leading to life-threatening complications such as bone marrow failure (BMF)"
    explanation: Replicative exhaustion of marrow precursors leads to bone marrow failure and hypocellularity.
  - reference: ORPHA:1775
    supports: SUPPORT
    snippet: "HP:0005528 | Bone marrow hypocellularity | Frequent (79-30%)"
    explanation: Orphanet classifies bone marrow hypocellularity as frequent in dyskeratosis congenita.
- category: Respiratory
  name: Pulmonary fibrosis
  description: >-
    Pulmonary fibrosis / interstitial lung disease occurs in a substantial minority
    of DC patients and may be the presenting feature of cryptic adult-onset disease.
    Diagnostic surgical lung biopsy and empirical immunosuppression carry increased
    risk in unrecognized DC-associated pulmonary fibrosis.
  phenotype_term:
    preferred_term: Pulmonary fibrosis
    term:
      id: HP:0002206
      label: Pulmonary fibrosis
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "increased risk for progressive bone marrow failure (BMF), myelodysplastic syndrome or acute myelogenous leukemia, solid tumors (usually squamous cell carcinoma of the head/neck or anogenital cancer), and pulmonary fibrosis."
    explanation: Pulmonary fibrosis is a recognized DC complication.
  - reference: PMID:34479523
    reference_title: "Pulmonary fibrosis in dyskeratosis congenita: a case report with a PRISMA-compliant systematic review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "PF caused by DC should be kept in mind by clinicians in the differential diagnosis of patients with unexplained PF and should be excluded before diagnostic surgical lung biopsy is undertaken or empirical immunosuppression therapy is prescribed."
    explanation: DC-associated pulmonary fibrosis should be excluded before lung biopsy or immunosuppression.
- category: Hepatic
  name: Hepatic fibrosis and portal hypertension
  description: >-
    Liver involvement is common in DC, typically with a cholestatic pattern of
    liver enzyme elevation; a subset progresses to clinically significant liver
    disease and portal hypertension, especially in recessive or TINF2-associated DC.
  phenotype_term:
    preferred_term: Periportal fibrosis
    term:
      id: HP:0001405
      label: Periportal fibrosis
  evidence:
  - reference: PMID:37184208
    reference_title: "Progression of liver disease and portal hypertension in dyskeratosis congenita and related telomere biology disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Liver abnormality (defined at baseline assessment by laboratory and/or radiological findings) was present in 72.4% of patients with predominantly cholestatic pattern of liver enzyme elevation."
    explanation: Liver abnormality was present in 72.4% of DC/TBD patients with cholestatic pattern.
  - reference: PMID:37184208
    reference_title: "Progression of liver disease and portal hypertension in dyskeratosis congenita and related telomere biology disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Clinically significant liver disease and portal hypertension developed in 17.2% of patients during the 6-year follow-up; this progression was mainly seen in patients with recessive or TINF2 -associated DC."
    explanation: 17.2% progressed to clinically significant liver disease and portal hypertension.
- category: Neoplasm
  name: Predisposition to myelodysplastic syndrome and acute myeloid leukemia
  description: >-
    DC carries an increased risk of myelodysplastic syndrome and acute myeloid
    leukemia due to genomic instability and clonal evolution in the failing marrow.
  phenotype_term:
    preferred_term: Myelodysplasia
    term:
      id: HP:0002863
      label: Myelodysplasia
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "increased risk for progressive bone marrow failure (BMF), myelodysplastic syndrome or acute myelogenous leukemia"
    explanation: DC predisposes to myelodysplastic syndrome and acute myeloid leukemia.
- category: Neoplasm
  name: Predisposition to squamous cell carcinoma
  description: >-
    DC patients are at increased risk of solid tumors, usually squamous cell
    carcinoma of the head and neck or anogenital region.
  phenotype_term:
    preferred_term: Squamous cell carcinoma
    term:
      id: HP:0002860
      label: Squamous cell carcinoma
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "solid tumors (usually squamous cell carcinoma of the head/neck or anogenital cancer)"
    explanation: DC predisposes to squamous cell carcinoma of the head/neck or anogenital region.
- category: Immunologic
  name: Immunodeficiency
  description: >-
    Immune dysfunction can occur in DC, reflecting telomere-driven exhaustion of
    the lymphoid compartment.
  phenotype_term:
    preferred_term: Immunodeficiency
    term:
      id: HP:0002721
      label: Immunodeficiency
  evidence:
  - reference: PMID:39371255
    reference_title: "Inherited Telomere Biology Disorders: Pathophysiology, Clinical Presentation, Diagnostics, and Treatment."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "a sufficient telomere reserve is particularly important in cells with high proliferative activity (e.g., hematopoiesis, immune cells, intestinal cells, liver, lung, and skin)."
    explanation: Immune cells require telomere reserve; telomere depletion compromises immune function.
- category: Neurologic
  name: Cerebellar hypoplasia (Hoyeraal-Hreidarsson syndrome)
  description: >-
    Cerebellar hypoplasia defines Hoyeraal-Hreidarsson syndrome, a severe
    early-onset DC variant.
  phenotype_term:
    preferred_term: Cerebellar hypoplasia
    term:
      id: HP:0001321
      label: Cerebellar hypoplasia
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "additional findings include cerebellar hypoplasia (Hoyeraal Hreidarsson syndrome)"
    explanation: Cerebellar hypoplasia defines the Hoyeraal-Hreidarsson severe DC variant.
- category: Ophthalmologic
  name: Exudative retinopathy (Revesz syndrome)
  description: >-
    Bilateral exudative retinopathy (a Coats-like retinal vascular exudation
    process) with intracranial calcifications defines Revesz syndrome, a severe DC
    variant. Mapped to HP:0030490 (Exudative vitreoretinopathy), which captures the
    retinal vascular exudation underlying this phenotype more accurately than serous
    retinal detachment.
  phenotype_term:
    preferred_term: Exudative retinopathy
    term:
      id: HP:0030490
      label: Exudative vitreoretinopathy
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "bilateral exudative retinopathy and intracranial calcifications (Revesz syndrome"
    explanation: Bilateral exudative retinopathy defines the Revesz severe DC variant.

genetic:
- name: DKC1
  gene_term:
    preferred_term: DKC1
    term:
      id: hgnc:2890
      label: DKC1
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  inheritance:
  - name: X-linked recessive inheritance
    inheritance_term:
      preferred_term: X-linked recessive inheritance
      term:
        id: HP:0001419
        label: X-linked recessive inheritance
  subtype: DKC1
  notes: >-
    DKC1 encodes dyskerin, an H/ACA snoRNP pseudouridine synthase required for
    stability of the telomerase RNA component; X-linked recessive, classically the
    most common and severe DC form.
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "ACD, CTC1, DKC1, NAF1, NHP2, NOP10, PARN, POT1, RPA1, RTEL1, STN1, TERC, TERT, TINF2, WRAP53, and ZCCHC8 are the genes in which pathogenic variants are known to cause DC/TBD"
    explanation: GeneReviews lists DKC1 among the 16 genes causing DC/TBD.
- name: TERT
  gene_term:
    preferred_term: TERT
    term:
      id: hgnc:11730
      label: TERT
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  inheritance:
  - name: Autosomal dominant inheritance
    inheritance_term:
      preferred_term: Autosomal dominant inheritance
      term:
        id: HP:0000006
        label: Autosomal dominant inheritance
  - name: Autosomal recessive inheritance
    inheritance_term:
      preferred_term: Autosomal recessive inheritance
      term:
        id: HP:0000007
        label: Autosomal recessive inheritance
  subtype: TERT
  notes: >-
    TERT encodes the catalytic protein subunit of telomerase; variants cause DC and
    cryptic adult-onset TBD with pulmonary/hepatic fibrosis.
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "ACD, CTC1, DKC1, NAF1, NHP2, NOP10, PARN, POT1, RPA1, RTEL1, STN1, TERC, TERT, TINF2, WRAP53, and ZCCHC8 are the genes in which pathogenic variants are known to cause DC/TBD"
    explanation: GeneReviews lists TERT among the 16 genes causing DC/TBD.
- name: TERC
  gene_term:
    preferred_term: TERC
    term:
      id: hgnc:11727
      label: TERC
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  inheritance:
  - name: Autosomal dominant inheritance
    inheritance_term:
      preferred_term: Autosomal dominant inheritance
      term:
        id: HP:0000006
        label: Autosomal dominant inheritance
  subtype: TERC
  notes: >-
    TERC encodes the telomerase RNA template subunit; autosomal dominant DC/TBD.
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "ACD, CTC1, DKC1, NAF1, NHP2, NOP10, PARN, POT1, RPA1, RTEL1, STN1, TERC, TERT, TINF2, WRAP53, and ZCCHC8 are the genes in which pathogenic variants are known to cause DC/TBD"
    explanation: GeneReviews lists TERC among the 16 genes causing DC/TBD.
- name: TINF2
  gene_term:
    preferred_term: TINF2
    term:
      id: hgnc:11824
      label: TINF2
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  inheritance:
  - name: Autosomal dominant inheritance
    inheritance_term:
      preferred_term: Autosomal dominant inheritance
      term:
        id: HP:0000006
        label: Autosomal dominant inheritance
  subtype: TINF2
  notes: >-
    TINF2 encodes shelterin TIN2; autosomal dominant, often severe early-onset DC.
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "ACD, CTC1, DKC1, NAF1, NHP2, NOP10, PARN, POT1, RPA1, RTEL1, STN1, TERC, TERT, TINF2, WRAP53, and ZCCHC8 are the genes in which pathogenic variants are known to cause DC/TBD"
    explanation: GeneReviews lists TINF2 among the 16 genes causing DC/TBD.
- name: RTEL1
  gene_term:
    preferred_term: RTEL1
    term:
      id: hgnc:15888
      label: RTEL1
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  inheritance:
  - name: Autosomal dominant inheritance
    inheritance_term:
      preferred_term: Autosomal dominant inheritance
      term:
        id: HP:0000006
        label: Autosomal dominant inheritance
  - name: Autosomal recessive inheritance
    inheritance_term:
      preferred_term: Autosomal recessive inheritance
      term:
        id: HP:0000007
        label: Autosomal recessive inheritance
  subtype: RTEL1
  notes: >-
    RTEL1 encodes a telomere-replication helicase; dominant or recessive DC,
    including Hoyeraal-Hreidarsson syndrome.
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "ACD, CTC1, DKC1, NAF1, NHP2, NOP10, PARN, POT1, RPA1, RTEL1, STN1, TERC, TERT, TINF2, WRAP53, and ZCCHC8 are the genes in which pathogenic variants are known to cause DC/TBD"
    explanation: GeneReviews lists RTEL1 among the 16 genes causing DC/TBD.
- name: CTC1
  gene_term:
    preferred_term: CTC1
    term:
      id: hgnc:26169
      label: CTC1
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  inheritance:
  - name: Autosomal recessive inheritance
    inheritance_term:
      preferred_term: Autosomal recessive inheritance
      term:
        id: HP:0000007
        label: Autosomal recessive inheritance
  subtype: CTC1
  notes: >-
    CTC1 encodes a CST-complex subunit supporting telomere C-strand replication;
    autosomal recessive DC overlapping Coats plus.
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "ACD, CTC1, DKC1, NAF1, NHP2, NOP10, PARN, POT1, RPA1, RTEL1, STN1, TERC, TERT, TINF2, WRAP53, and ZCCHC8 are the genes in which pathogenic variants are known to cause DC/TBD"
    explanation: GeneReviews lists CTC1 among the 16 genes causing DC/TBD.
- name: RPA1
  gene_term:
    preferred_term: RPA1
    term:
      id: hgnc:10289
      label: RPA1
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  inheritance:
  - name: Autosomal dominant inheritance
    inheritance_term:
      preferred_term: Autosomal dominant inheritance
      term:
        id: HP:0000006
        label: Autosomal dominant inheritance
  subtype: RPA1
  notes: >-
    RPA1 encodes a single-stranded DNA-binding protein involved in telomere
    replication; autosomal dominant DC/TBD.
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "ACD, CTC1, DKC1, NAF1, NHP2, NOP10, PARN, POT1, RPA1, RTEL1, STN1, TERC, TERT, TINF2, WRAP53, and ZCCHC8 are the genes in which pathogenic variants are known to cause DC/TBD"
    explanation: GeneReviews lists RPA1 among the 16 genes causing DC/TBD.
- name: ACD
  gene_term:
    preferred_term: ACD
    term:
      id: hgnc:25070
      label: ACD
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  inheritance:
  - name: Autosomal dominant inheritance
    inheritance_term:
      preferred_term: Autosomal dominant inheritance
      term:
        id: HP:0000006
        label: Autosomal dominant inheritance
  - name: Autosomal recessive inheritance
    inheritance_term:
      preferred_term: Autosomal recessive inheritance
      term:
        id: HP:0000007
        label: Autosomal recessive inheritance
  subtype: ACD
  notes: >-
    ACD encodes shelterin TPP1, which recruits and stimulates telomerase; dominant
    or recessive DC.
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "ACD, CTC1, DKC1, NAF1, NHP2, NOP10, PARN, POT1, RPA1, RTEL1, STN1, TERC, TERT, TINF2, WRAP53, and ZCCHC8 are the genes in which pathogenic variants are known to cause DC/TBD"
    explanation: GeneReviews lists ACD among the 16 genes causing DC/TBD.
- name: NHP2
  gene_term:
    preferred_term: NHP2
    term:
      id: hgnc:14377
      label: NHP2
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  inheritance:
  - name: Autosomal recessive inheritance
    inheritance_term:
      preferred_term: Autosomal recessive inheritance
      term:
        id: HP:0000007
        label: Autosomal recessive inheritance
  subtype: NHP2
  notes: >-
    NHP2 encodes an H/ACA snoRNP component required for telomerase RNA stability;
    autosomal recessive DC.
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "ACD, CTC1, DKC1, NAF1, NHP2, NOP10, PARN, POT1, RPA1, RTEL1, STN1, TERC, TERT, TINF2, WRAP53, and ZCCHC8 are the genes in which pathogenic variants are known to cause DC/TBD"
    explanation: GeneReviews lists NHP2 among the 16 genes causing DC/TBD.
- name: NOP10
  gene_term:
    preferred_term: NOP10
    term:
      id: hgnc:14378
      label: NOP10
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  inheritance:
  - name: Autosomal recessive inheritance
    inheritance_term:
      preferred_term: Autosomal recessive inheritance
      term:
        id: HP:0000007
        label: Autosomal recessive inheritance
  subtype: NOP10
  notes: >-
    NOP10 encodes an H/ACA snoRNP component required for telomerase RNA stability;
    autosomal recessive DC.
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "ACD, CTC1, DKC1, NAF1, NHP2, NOP10, PARN, POT1, RPA1, RTEL1, STN1, TERC, TERT, TINF2, WRAP53, and ZCCHC8 are the genes in which pathogenic variants are known to cause DC/TBD"
    explanation: GeneReviews lists NOP10 among the 16 genes causing DC/TBD.
- name: PARN
  gene_term:
    preferred_term: PARN
    term:
      id: hgnc:8609
      label: PARN
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  inheritance:
  - name: Autosomal dominant inheritance
    inheritance_term:
      preferred_term: Autosomal dominant inheritance
      term:
        id: HP:0000006
        label: Autosomal dominant inheritance
  - name: Autosomal recessive inheritance
    inheritance_term:
      preferred_term: Autosomal recessive inheritance
      term:
        id: HP:0000007
        label: Autosomal recessive inheritance
  subtype: PARN
  notes: >-
    PARN encodes a deadenylase required for TERC maturation; dominant or recessive
    DC, associated with pulmonary fibrosis.
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "ACD, CTC1, DKC1, NAF1, NHP2, NOP10, PARN, POT1, RPA1, RTEL1, STN1, TERC, TERT, TINF2, WRAP53, and ZCCHC8 are the genes in which pathogenic variants are known to cause DC/TBD"
    explanation: GeneReviews lists PARN among the 16 genes causing DC/TBD.
- name: WRAP53
  gene_term:
    preferred_term: WRAP53
    term:
      id: hgnc:25522
      label: WRAP53
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  inheritance:
  - name: Autosomal recessive inheritance
    inheritance_term:
      preferred_term: Autosomal recessive inheritance
      term:
        id: HP:0000007
        label: Autosomal recessive inheritance
  subtype: WRAP53
  notes: >-
    WRAP53 (TCAB1) traffics telomerase to Cajal bodies; autosomal recessive DC.
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "ACD, CTC1, DKC1, NAF1, NHP2, NOP10, PARN, POT1, RPA1, RTEL1, STN1, TERC, TERT, TINF2, WRAP53, and ZCCHC8 are the genes in which pathogenic variants are known to cause DC/TBD"
    explanation: GeneReviews lists WRAP53 among the 16 genes causing DC/TBD.
- name: POT1
  gene_term:
    preferred_term: POT1
    term:
      id: hgnc:17284
      label: POT1
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  inheritance:
  - name: Autosomal recessive inheritance
    inheritance_term:
      preferred_term: Autosomal recessive inheritance
      term:
        id: HP:0000007
        label: Autosomal recessive inheritance
  subtype: POT1
  notes: >-
    POT1 encodes a shelterin protein binding telomeric single-stranded DNA;
    pathogenic variants reduce ssDNA binding and expand the DC allelic series.
  evidence:
  - reference: PMID:39198715
    reference_title: "The evolving genetic landscape of telomere biology disorder dyskeratosis congenita."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "we have also identified several novel variants in POT1 and ZCCHC8 in multiple cases from different families expanding the allelic series of DC and DCL phenotypes."
    explanation: Novel POT1 variants expand the DC allelic series.
- name: POLA1
  gene_term:
    preferred_term: POLA1
    term:
      id: hgnc:9173
      label: POLA1
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  inheritance:
  - name: X-linked recessive inheritance
    inheritance_term:
      preferred_term: X-linked recessive inheritance
      term:
        id: HP:0001419
        label: X-linked recessive inheritance
  notes: >-
    POLA1 (DNA polymerase alpha catalytic subunit) was newly implicated as an
    X-linked DC gene in 2024; pathogenic variants disrupt protein-protein
    interactions with primase, the CST complex, and shelterin that are critical for
    telomere maintenance.
  evidence:
  - reference: PMID:39198715
    reference_title: "The evolving genetic landscape of telomere biology disorder dyskeratosis congenita."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "This led us to identify several novel pathogenic variants within known genetic loci and in the novel X-linked gene, POLA1."
    explanation: POLA1 is a newly identified X-linked DC gene.
  - reference: PMID:39198715
    reference_title: "The evolving genetic landscape of telomere biology disorder dyskeratosis congenita."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "Functional characterisation of novel POLA1 and POT1 variants, revealed pathogenic effects on protein-protein interactions with primase, CTC1-STN1-TEN1 (CST) and shelterin subunit complexes, that are critical for telomere maintenance."
    explanation: Functional studies show POLA1 variants disrupt CST/shelterin/primase interactions required for telomere maintenance.
- name: NAF1
  gene_term:
    preferred_term: NAF1
    term:
      id: hgnc:25126
      label: NAF1
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  inheritance:
  - name: Autosomal dominant inheritance
    inheritance_term:
      preferred_term: Autosomal dominant inheritance
      term:
        id: HP:0000006
        label: Autosomal dominant inheritance
  subtype: NAF1
  notes: >-
    NAF1 encodes an H/ACA ribonucleoprotein assembly factor required for biogenesis
    and stability of the telomerase RNA component (TERC).
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "ACD, CTC1, DKC1, NAF1, NHP2, NOP10, PARN, POT1, RPA1, RTEL1, STN1, TERC, TERT, TINF2, WRAP53, and ZCCHC8 are the genes in which pathogenic variants are known to cause DC/TBD"
    explanation: GeneReviews lists NAF1 among the 16 genes causing DC/TBD.
- name: STN1
  gene_term:
    preferred_term: STN1
    term:
      id: hgnc:26200
      label: STN1
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  inheritance:
  - name: Autosomal recessive inheritance
    inheritance_term:
      preferred_term: Autosomal recessive inheritance
      term:
        id: HP:0000007
        label: Autosomal recessive inheritance
  subtype: STN1
  notes: >-
    STN1 encodes a subunit of the CST (CTC1-STN1-TEN1) complex required for telomere
    replication and C-strand fill-in synthesis.
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "ACD, CTC1, DKC1, NAF1, NHP2, NOP10, PARN, POT1, RPA1, RTEL1, STN1, TERC, TERT, TINF2, WRAP53, and ZCCHC8 are the genes in which pathogenic variants are known to cause DC/TBD"
    explanation: GeneReviews lists STN1 among the 16 genes causing DC/TBD.
- name: ZCCHC8
  gene_term:
    preferred_term: ZCCHC8
    term:
      id: hgnc:25265
      label: ZCCHC8
  relationship_type: CAUSATIVE
  variant_origin: GERMLINE
  inheritance:
  - name: Autosomal dominant inheritance
    inheritance_term:
      preferred_term: Autosomal dominant inheritance
      term:
        id: HP:0000006
        label: Autosomal dominant inheritance
  subtype: ZCCHC8
  notes: >-
    ZCCHC8 encodes a component of the nuclear exosome targeting (NEXT) complex
    involved in processing and quality control of the telomerase RNA component.
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "ACD, CTC1, DKC1, NAF1, NHP2, NOP10, PARN, POT1, RPA1, RTEL1, STN1, TERC, TERT, TINF2, WRAP53, and ZCCHC8 are the genes in which pathogenic variants are known to cause DC/TBD"
    explanation: GeneReviews lists ZCCHC8 among the 16 genes causing DC/TBD.
  - reference: PMID:39198715
    reference_title: "The evolving genetic landscape of telomere biology disorder dyskeratosis congenita."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "we have also identified several novel variants in POT1 and ZCCHC8 in multiple cases from different families expanding the allelic series of DC and DCL phenotypes."
    explanation: Novel ZCCHC8 variants expand the DC allelic series.

treatments:
- name: Hematopoietic stem cell transplantation
  description: >-
    Hematopoietic cell transplantation is the only curative treatment for bone
    marrow failure and leukemia in DC, but historically has poor long-term outcome
    due to treatment toxicity. Radiation- and alkylator-reduced conditioning is
    favored, and related donors carrying the familial variant should be avoided.
  treatment_term:
    preferred_term: hematopoietic stem cell transplantation
    term:
      id: MAXO:0000747
      label: hematopoietic stem cell transplantation
  therapeutic_modality: CELL_THERAPY
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Hematopoietic cell transplantation (HCT) is the only curative treatment for BMF and leukemia, but long-term outcome has historically been poor due to treatment toxicity"
    explanation: HCT is the only curative treatment for DC marrow failure/leukemia but is toxicity-limited.
  target_mechanisms:
  - target: Stem Cell Exhaustion in High-Turnover Tissues
    treatment_effect: MODULATES
    description: >-
      HSCT replaces the dysfunctional short-telomere hematopoietic stem cell
      pool with donor-derived cells, rescuing hematopoiesis and reducing
      leukemia risk; it does not correct the underlying telomere maintenance
      defect in non-hematopoietic tissues.
- name: Androgen therapy (danazol)
  description: >-
    Androgen therapy (e.g., danazol, oxymetholone) can improve blood counts and may
    be considered for bone marrow failure when a suitable transplant donor is not
    available. The combination of androgens with granulocyte colony-stimulating
    factor should be avoided because it has been associated with splenic rupture;
    monitoring of CBC, liver function, and liver ultrasound is recommended.
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: danazol
      term:
        id: CHEBI:4315
        label: danazol
    - preferred_term: oxymetholone
      term:
        id: CHEBI:7864
        label: oxymetholone
  therapeutic_modality: SMALL_MOLECULE
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "if a suitable donor is not available, androgen therapy may be considered for BMF."
    explanation: Androgen therapy is an option for bone marrow failure when transplant is not available.
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "the combination of androgens and granulocyte colony-stimulating factor in treatment of BMF (has been associated with splenic rupture)"
    explanation: GeneReviews Agents/Circumstances to Avoid - androgen plus G-CSF risks splenic rupture.
  target_mechanisms:
  - target: Impaired Telomere Maintenance
    treatment_effect: MODULATES
    description: >-
      Androgens (danazol, oxymetholone) upregulate TERT expression, boosting
      telomerase activity in hematopoietic progenitors and partially reversing
      the telomere maintenance defect.
  - target: Critically Short Telomeres and Replicative Senescence
    treatment_effect: MODULATES
    description: >-
      By stimulating TERT, androgen therapy can slow the rate of telomere
      attrition in bone marrow progenitors, delaying progression to replicative
      senescence and improving blood counts.
- name: Lung transplantation
  description: >-
    Treatment of pulmonary fibrosis is primarily supportive, although lung
    transplantation may be considered for end-stage disease.
  treatment_term:
    preferred_term: organ transplantation
    term:
      id: MAXO:0010039
      label: organ transplantation
  therapeutic_modality: SURGERY
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Treatment of pulmonary fibrosis is primarily supportive, although lung transplantation may be considered."
    explanation: Lung transplantation may be considered for DC-associated pulmonary fibrosis.
  target_mechanisms:
  - target: Stem Cell Exhaustion in High-Turnover Tissues
    treatment_effect: MODULATES
    description: >-
      Lung transplantation replaces end-stage fibrotic lung tissue; it does not
      address the underlying telomere biology defect and DC patients face
      elevated post-transplant risks from impaired regenerative capacity in
      other high-turnover tissues.
- name: Cancer surveillance and supportive care
  description: >-
    Surveillance is central to DC management, including annual CBC and bone marrow
    evaluation, monthly oral/head/neck self-examination with annual otolaryngology
    and dermatology screening, and annual pulmonary function tests. Of note, cancer
    therapy may pose an increased risk of prolonged cytopenias and pulmonary and
    hepatic toxicity, and non-irradiated/leukodepleted blood products should be used.
  treatment_term:
    preferred_term: supportive care
    term:
      id: MAXO:0000950
      label: supportive care
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "cancer therapy may pose an increased risk for prolonged cytopenias as well as pulmonary and hepatic toxicity."
    explanation: GeneReviews notes increased risk from cancer therapy, motivating surveillance and supportive care.
- name: Genetic counseling
  description: >-
    Genetic counseling addresses gene-specific mode of inheritance; once the
    familial variant is identified, prenatal and preimplantation genetic testing
    are possible. Family members should not donate blood if HCT is being considered,
    and potential related donors require telomere length and/or molecular testing.
  treatment_term:
    preferred_term: Genetic Counseling
    term:
      id: NCIT:C15240
      label: Genetic Counseling
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Once the DC/TBD-related pathogenic variant(s) have been identified in an affected family member, prenatal and preimplantation genetic testing are possible."
    explanation: Genetic counseling enables prenatal/preimplantation testing once the variant is known.

discussions:
- discussion_id: gap_dc_unexplained_genetic_cause
  prompt: >-
    What accounts for the roughly 20% of clinically diagnosed dyskeratosis
    congenita / telomere biology disorder cases in which no pathogenic variant is
    identified in any of the 16 known DC/TBD genes?
  kind: KNOWLEDGE_GAP
  status: OPEN
  attaches_to:
  - pathophysiology#Impaired Telomere Maintenance
  rationale: >-
    GeneReviews reports that pathogenic variants in the 16 known DC/TBD genes are
    identified in approximately 80% of individuals meeting clinical diagnostic
    criteria, leaving roughly one in five clinically diagnosed patients genetically
    unexplained. These cases likely harbor variants in undiscovered genes,
    non-coding or structural variants in known loci, or somatic/mosaic events not
    captured by standard testing. Resolving this gap would extend the mechanistic
    chain (impaired telomere maintenance) to currently uncharacterized molecular
    causes and improve molecular diagnosis and counseling.
  evidence:
  - reference: PMID:20301779
    reference_title: "Dyskeratosis Congenita and Related Telomere Biology Disorders."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "in approximately 80% of individuals who meet"
    explanation: >-
      GeneReviews reports a genetic diagnostic yield of approximately 80%,
      implying roughly 20% of clinically diagnosed DC/TBD remains genetically
      unexplained.
datasets: []
📚

References & Deep Research

References

1
Dyskeratosis Congenita and Related Telomere Biology Disorders.
No top-level findings curated for this source.

Deep Research

1
Falcon
Disease Characteristics Research Template
Edison Scientific Literature 47 citations 2026-06-05T14:39:23.053674

Question: You are an expert researcher providing comprehensive, well-cited information.

Provide detailed information focusing on: 1. Key concepts and definitions with current understanding 2. Recent developments and latest research (prioritize 2023-2024 sources) 3. Current applications and real-world implementations 4. Expert opinions and analysis from authoritative sources 5. Relevant statistics and data from recent studies

Format as a comprehensive research report with proper citations. Include URLs and publication dates where available. Always prioritize recent, authoritative sources and provide specific citations for all major claims.

Disease Characteristics Research Template

Target Disease

  • Disease Name: Dyskeratosis Congenita
  • MONDO ID: (if available)
  • Category: Mendelian

Research Objectives

Please provide a comprehensive research report on Dyskeratosis Congenita covering all of the disease characteristics listed below. This report will be used to populate a disease knowledge base entry. Be thorough and cite primary literature (PMID preferred) for all claims.

For each section, suggested databases/resources are listed. These are the first places you should search for information on each topic.


1. Disease Information

Search first: OMIM, Orphanet, ICD-10/ICD-11, MeSH, PubMed

  • What is the disease? Provide a concise overview.
  • What are the key identifiers? (OMIM, Orphanet, ICD-10/ICD-11, MeSH, Mondo)
  • What are the common synonyms and alternative names?
  • Is the information derived from individual patients (e.g., EHR) or aggregated disease-level resources?

2. Etiology

  • Disease Causal Factors: What are the primary causes? (genetic, environmental, infectious, mechanistic)
  • Risk Factors:

    Search first: PubMed, Cochrane Library, UpToDate, clinical guidelines, ClinVar, ClinGen, GWAS Catalog, PheGenI, CTD, CDC, WHO, epidemiological databases

  • Genetic risk factors (causal variants, susceptibility loci, modifier genes)
  • Environmental risk factors (toxins, lifestyle, occupational exposures, age, sex, family history)
  • Protective Factors:

    Search first: PubMed, Cochrane Library, clinical trial databases, GWAS Catalog, gnomAD, WHO, CDC, nutrition databases

  • Genetic protective factors (protective variants, modifier alleles)
  • Environmental protective factors (diet, lifestyle, exposures that reduce risk)
  • Gene-Environment Interactions: How do genetic and environmental factors interact to influence disease?

    Search first: CTD, PubMed, PheGenI, GxE databases

3. Phenotypes

Search first: HPO (Human Phenotype Ontology), OMIM, Orphanet, PubMed, clinicaltrials.gov, MedDRA, SNOMED CT, DECIPHER, LOINC

For each phenotype, provide: - Phenotype type: symptoms, clinical signs, physical manifestations, behavioral changes, or laboratory abnormalities

For symptoms/signs: HPO, OMIM, Orphanet, PubMed For behavioral changes: HPO, DSM, RDoC (Research Domain Criteria), PubMed For laboratory abnormalities: LOINC, SNOMED CT, LabTests Online, PubMed - Phenotype characteristics: Search first: OMIM, Orphanet, HPO, PubMed - Age of symptom onset (neonatal, childhood, adult-onset, late-onset) - Symptom severity (mild, moderate, severe, variable) - Symptom progression (stable, progressive, episodic, fluctuating) - Frequency among affected individuals (percentage or qualitative) - Quality of life impact: Effects on daily functioning and well-being (per-phenotype when possible) Search first: EQ-5D database, SF-36, WHO QOL databases, PubMed - Suggest HPO (Human Phenotype Ontology) terms for each phenotype

4. Genetic/Molecular Information

  • Causal Genes: Gene mutations or chromosomal abnormalities responsible for disease (gene symbols, OMIM IDs)

    Search first: OMIM, ClinVar, HGMD, Ensembl, NCBI Gene

  • Pathogenic Variants:
  • Affected genes (gene symbols, HGNC IDs) > Search first: OMIM, NCBI Gene, Ensembl, HGNC, UniProt, GeneCards
  • Variant classification (pathogenic, likely pathogenic, VUS per ACMG/AMP guidelines) > Search first: ClinVar, ClinGen, ACMG/AMP guidelines, VarSome
  • Variant type/class (missense, frameshift, nonsense, splice-site, structural)
  • Allele frequency in population databases > Search first: gnomAD, 1000 Genomes, ExAC, TOPMed, dbSNP
  • Somatic vs germline origin > Search first: COSMIC (somatic), ClinVar, ICGC, TCGA
  • Functional consequences (loss of function, gain of function, dominant negative)
  • Modifier Genes: Genes that modify disease severity or expression
  • Epigenetic Information: DNA methylation, histone modifications, chromatin changes affecting disease

    Search first: ENCODE, Roadmap Epigenomics, MethBase, DiseaseMeth

  • Chromosomal Abnormalities: Large-scale genetic changes (aneuploidy, translocations, inversions)

    Search first: DECIPHER, ClinVar, ECARUCA, UCSC Genome Browser

5. Environmental Information

  • Environmental Factors: Non-genetic contributing factors (toxins, radiation, pollution, occupational exposure)

    Search first: CTD (Comparative Toxicogenomics Database), TOXNET, PubMed, EPA databases

  • Lifestyle Factors: Behavioral factors (smoking, diet, exercise, alcohol consumption)

    Search first: CDC databases, WHO, PubMed, NHANES

  • Infectious Agents: If applicable, pathogens causing or triggering disease (bacteria, viruses, fungi, parasites)

    Search first: NCBI Taxonomy, ViPR, BV-BRC, MicrobeDB, GIDEON

6. Mechanism / Pathophysiology

  • Molecular Pathways: Specific signaling cascades or biochemical pathways involved (Wnt, MAPK, mTOR, PI3K-AKT, etc.)

    Search first: KEGG, Reactome, WikiPathways, PathBank, BioCyc

  • Cellular Processes: Cell-level mechanisms (apoptosis, autophagy, cell cycle dysregulation, inflammation, etc.)

    Search first: Gene Ontology (GO), Reactome, KEGG, PubMed

  • Protein Dysfunction: How protein structure or function is altered (misfolding, aggregation, loss of function, gain of function)

    Search first: UniProt, PDB (Protein Data Bank), InterPro, Pfam, AlphaFold

  • Metabolic Changes: Alterations in metabolic processes (energy metabolism, lipid metabolism, amino acid metabolism)

    Search first: KEGG, BioCyc, HMDB (Human Metabolome Database), BRENDA

  • Immune System Involvement: Role of immune response (autoimmunity, immunodeficiency, chronic inflammation)

    Search first: ImmPort, Immunome Database, IEDB, Gene Ontology

  • Tissue Damage Mechanisms: How tissues/ are injured (oxidative stress, ischemia, fibrosis, necrosis)

    Search first: PubMed, Gene Ontology, Reactome

  • Biochemical Abnormalities: Specific molecular defects (enzyme deficiencies, receptor dysfunction, ion channel defects)

    Search first: BRENDA, UniProt, KEGG, OMIM, PubMed

  • Epigenetic Changes: DNA methylation, histone modifications affecting gene expression in disease

    Search first: ENCODE, Roadmap Epigenomics, MethBase, DiseaseMeth

  • Molecular Profiling (if available):
  • Transcriptomics/gene expression changes > Search first: GEO (Gene Expression Omnibus), ArrayExpress, GTEx, Human Cell Atlas, SRA
  • Proteomics findings > Search first: PRIDE, ProteomeXchange, Human Protein Atlas, STRING, BioGRID
  • Metabolomics signatures > Search first: MetaboLights, Metabolomics Workbench, HMDB, METLIN
  • Lipidomics alterations > Search first: LIPID MAPS, SwissLipids, LipidHome, Metabolomics Workbench
  • Genomic structural features > Search first: UCSC Genome Browser, Ensembl, NCBI, dbVar, DGV
  • Advanced Technologies (if applicable):
  • Single-cell analysis findings (cell-type specific mechanisms, cellular heterogeneity) > Search first: Human Cell Atlas, Single Cell Portal, GEO, CELLxGENE
  • Spatial transcriptomics findings > Search first: GEO, Spatial Research, Vizgen, 10x Genomics data
  • Multi-omics integration results > Search first: TCGA, ICGC, cBioPortal, LinkedOmics, PubMed
  • Functional genomics screens (CRISPR, RNAi) > Search first: DepMap, GenomeRNAi, PubMed, BioGRID ORCS

For each mechanism, describe: - The causal chain from initial trigger to clinical manifestation - Which mechanisms are upstream vs downstream - What cell types and biological processes are involved - Suggest GO terms for biological processes and CL terms for cell types

7. Anatomical Structures Affected

  • Organ Level:
  • Primary organs directly affected
  • Secondary organ involvement (complications, secondary effects)
  • Body systems involved (cardiovascular, nervous, digestive, respiratory, endocrine, etc.)

    Search first: Uberon, FMA (Foundational Model of Anatomy), OMIM, HPO, ICD-11, MeSH, SNOMED CT

  • Tissue and Cell Level:
  • Specific tissue types affected (epithelial, connective, muscle, nervous)
  • Specific cell populations targeted (with Cell Ontology terms)

    Search first: Uberon, Human Protein Atlas, Cell Ontology, Human Cell Atlas, CellMarker, PanglaoDB

  • Subcellular Level:
  • Cellular compartments involved (mitochondria, nucleus, ER, lysosomes) (with GO Cellular Component terms)

    Search first: Gene Ontology (Cellular Component), UniProt, Human Protein Atlas

  • Localization:
  • Specific anatomical sites (with UBERON terms) > Search first: FMA, Uberon, NeuroNames (for brain), SNOMED CT
  • Lateralization (unilateral, bilateral, asymmetric) > Search first: HPO, clinical literature, imaging databases

8. Temporal Development

  • Onset:
  • Typical age of onset (congenital, pediatric, adult, geriatric)
  • Onset pattern (acute, subacute, chronic, insidious)

    Search first: OMIM, Orphanet, HPO, PubMed

  • Progression:
  • Disease stages (early, intermediate, advanced, end-stage) > Search first: Cancer Staging Manual (AJCC), WHO classifications, PubMed
  • Progression rate (rapid, slow, variable)
  • Disease course pattern (episodic, relapsing-remitting, progressive, stable)
  • Disease duration (self-limited, chronic lifelong)

    Search first: Disease registries, longitudinal cohort databases, natural history studies, PubMed, Orphanet, OMIM

  • Patterns:
  • Remission patterns (spontaneous, treatment-induced) > Search first: Clinical trial databases, disease registries, PubMed
  • Critical periods (time windows of vulnerability or opportunity for intervention) > Search first: PubMed, developmental biology databases, clinical guidelines

9. Inheritance and Population

  • Epidemiology:
  • Prevalence (cases per 100,000 at given time)
  • Incidence (new cases per 100,000 per year)

    Search first: Orphanet, CDC, WHO, GBD (Global Burden of Disease), national registries, SEER, disease registries

  • For Genetic Etiology:
  • Inheritance pattern (AD, AR, X-linked, mitochondrial, multifactorial, polygenic) > Search first: OMIM, Orphanet, ClinVar, GTR (Genetic Testing Registry)
  • Penetrance (complete, incomplete, age-dependent) > Search first: ClinVar, OMIM, PubMed, ClinGen
  • Expressivity (variable, consistent) > Search first: OMIM, ClinVar, PubMed
  • Genetic anticipation (increasing severity in successive generations) > Search first: OMIM, PubMed (especially for repeat expansion disorders)
  • Germline mosaicism > Search first: ClinVar, OMIM, genetic counseling literature, PubMed
  • Founder effects (population-specific mutations) > Search first: gnomAD, population genetics databases, PubMed
  • Consanguinity role > Search first: OMIM, population studies, genetic counseling resources
  • Carrier frequency > Search first: gnomAD, carrier screening databases, GeneReviews, GTR
  • Population Demographics:
  • Affected populations (ethnic or demographic groups with higher prevalence) > Search first: gnomAD, 1000 Genomes, PAGE Study, PubMed, population registries
  • Geographic distribution (endemic areas, regional variation) > Search first: WHO, CDC, GBD, Orphanet, geographic epidemiology databases
  • Geographic distribution of specific variants
  • Sex ratio (male:female) > Search first: Disease registries, OMIM, PubMed, epidemiological databases
  • Age distribution of affected individuals > Search first: CDC, disease registries, SEER, Orphanet

10. Diagnostics

  • Clinical Tests:
  • Laboratory tests (blood, urine, tissue chemistry, specific enzyme assays) > Search first: LOINC, LabTests Online, PubMed
  • Biomarkers (proteins, metabolites, genetic markers, circulating biomarkers) > Search first: FDA Biomarker List, BEST (Biomarkers, EndpointS, and other Tools), PubMed
  • Imaging studies (X-ray, CT, MRI, PET, ultrasound) > Search first: RadLex, DICOM, Radiopaedia, imaging databases
  • Functional tests (pulmonary function, cardiac stress tests) > Search first: LOINC, clinical guidelines, PubMed
  • Electrophysiology (EEG, EMG, ECG, nerve conduction studies) > Search first: LOINC, clinical neurophysiology databases, PubMed
  • Biopsy findings (histopathology, immunohistochemistry) > Search first: SNOMED CT, College of American Pathologists resources, PubMed
  • Pathology findings (microscopic examination) > Search first: SNOMED CT, Digital Pathology databases, PubMed
  • Genetic Testing:

    Search first: GTR (Genetic Testing Registry), GeneReviews, ClinGen

  • Overview of recommended genetic testing approach
  • Whole genome sequencing (WGS) utility > Search first: GTR, ClinVar, GEL (Genomics England), gnomAD
  • Whole exome sequencing (WES) utility > Search first: GTR, ClinVar, OMIM, GeneMatcher
  • Gene panels (which panels, which genes) > Search first: GTR, ClinVar, laboratory-specific databases
  • Single gene testing > Search first: GTR, ClinVar, OMIM, GeneReviews
  • Chromosomal microarray (CMA) > Search first: DECIPHER, ClinVar, dbVar, ECARUCA
  • Karyotyping > Search first: Chromosome Abnormality Database, ClinVar, cytogenetics resources
  • FISH > Search first: ClinVar, cytogenetics databases, PubMed
  • Mitochondrial DNA testing > Search first: MITOMAP, MSeqDR, ClinVar, GTR
  • Repeat expansion testing > Search first: GTR, ClinVar, repeat expansion databases, PubMed
  • Omics-Based Diagnostics (if applicable):
  • RNA sequencing / transcriptomics > Search first: GEO, ArrayExpress, GTEx, RNA-seq databases
  • Proteomics > Search first: PRIDE, ProteomeXchange, FDA Biomarker database
  • Metabolomics > Search first: MetaboLights, Metabolomics Workbench, HMDB
  • Epigenomics > Search first: GEO, ENCODE, Roadmap Epigenomics, MethBase
  • Liquid biopsy > Search first: COSMIC, ClinVar, liquid biopsy databases, PubMed
  • Clinical Criteria:
  • Standardized diagnostic criteria (DSM, ICD, society guidelines) > Search first: DSM-5, ICD-11, clinical society guidelines, UpToDate
  • Differential diagnosis (other conditions to rule out, with distinguishing features) > Search first: DynaMed, UpToDate, clinical decision support systems
  • Screening:
  • Screening methods for asymptomatic individuals (newborn screening, carrier screening, cascade screening) > Search first: ACMG recommendations, CDC newborn screening, GTR

11. Outcome/Prognosis

  • Survival and Mortality:
  • Survival rate (5-year, 10-year, overall) > Search first: SEER, cancer registries, disease-specific registries, PubMed
  • Life expectancy (with and without treatment if applicable) > Search first: Orphanet, disease registries, actuarial databases, PubMed
  • Mortality rate > Search first: CDC, WHO, GBD, national mortality databases
  • Disease-specific mortality (deaths directly attributable to disease) > Search first: Disease registries, CDC Wonder, GBD, PubMed
  • Morbidity and Function:
  • Morbidity (disease-related disability and health impacts) > Search first: GBD, WHO, disability databases, PubMed
  • Disability outcomes (long-term functional impairments) > Search first: ICF (International Classification of Functioning), disability registries
  • Quality of life measures (EQ-5D, SF-36, PROMIS, disease-specific tools) > Search first: EQ-5D database, SF-36, PROMIS, PubMed
  • Disease Course:
  • Complications (secondary problems: infections, organ failure, etc.) > Search first: ICD codes, disease registries, clinical databases, PubMed
  • Recovery potential (likelihood and extent of recovery, with vs without treatment) > Search first: Natural history studies, rehabilitation databases, PubMed
  • Prediction:
  • Prognostic factors (age, disease severity, biomarkers, treatment response) > Search first: Prognostic models databases, clinical calculators, PubMed
  • Prognostic biomarkers (molecular markers predicting disease course) > Search first: FDA Biomarker database, PubMed, cancer prognostic databases

12. Treatment

  • Pharmacotherapy:
  • Pharmacological treatments (drug names, drug classes, mechanisms of action) > Search first: DrugBank, RxNorm, ATC classification, DailyMed, FDA databases
  • Pharmacogenomics (how genetic variants affect drug metabolism, efficacy, toxicity) > Search first: PharmGKB, CPIC (Clinical Pharmacogenetics), FDA Table of PGx Biomarkers
  • Advanced Therapeutics:
  • Gene therapy (viral vectors, CRISPR, gene replacement, gene editing) > Search first: ClinicalTrials.gov, FDA gene therapy database, ASGCT resources
  • Cell therapy (stem cell transplant, CAR-T, cellular therapeutics) > Search first: ClinicalTrials.gov, FDA cell therapy database, FACT standards
  • RNA-based therapies (ASOs, siRNA, mRNA therapies) > Search first: ClinicalTrials.gov, FDA approvals, PubMed
  • Targeted therapies (treatments directed at specific molecular targets) > Search first: My Cancer Genome, OncoKB, ClinicalTrials.gov, FDA approvals
  • Immunotherapies (checkpoint inhibitors, monoclonal antibodies) > Search first: Cancer Immunotherapy Database, FDA approvals, ClinicalTrials.gov
  • Surgical and Interventional:
  • Surgical interventions (types of surgery, timing, outcomes) > Search first: CPT codes, surgical registries, clinical guidelines, PubMed
  • Supportive and Rehabilitative:
  • Supportive care (symptom management, pain control, nutrition) > Search first: Clinical guidelines, Cochrane Library, PubMed
  • Rehabilitation (physical therapy, occupational therapy, speech therapy) > Search first: Rehabilitation medicine databases, clinical guidelines, PubMed
  • Experimental:
  • Experimental treatments in clinical trials (with NCT identifiers if available) > Search first: ClinicalTrials.gov, EU Clinical Trials Register, WHO ICTRP
  • Treatment Outcomes:
  • Treatment response rates > Search first: Clinical trial databases, FDA reviews, systematic reviews, PubMed
  • Side effects and adverse events > Search first: FDA Adverse Event Reporting System (FAERS), MedWatch, PubMed
  • Treatment Strategy:
  • Treatment algorithms (clinical pathways, decision trees) > Search first: Clinical practice guidelines, NCCN Guidelines, UpToDate
  • Combination therapies > Search first: ClinicalTrials.gov, treatment guidelines, PubMed
  • Personalized medicine approaches (genotype-guided treatment) > Search first: My Cancer Genome, CIViC, PharmGKB, precision medicine databases

For each treatment, suggest MAXO (Medical Action Ontology) terms where applicable.

13. Prevention

  • Prevention Levels:
  • Primary prevention (preventing disease occurrence: vaccination, risk factor modification) > Search first: CDC, WHO, USPSTF recommendations, Cochrane Library
  • Secondary prevention (early detection and treatment: screening programs, early intervention) > Search first: USPSTF, CDC screening guidelines, WHO
  • Tertiary prevention (preventing complications in those with disease) > Search first: Clinical guidelines, disease management protocols, PubMed
  • Immunization: Vaccine strategies (if applicable)

    Search first: CDC vaccine schedules, WHO immunization, FDA vaccine database

  • Screening and Early Detection:
  • Screening programs (population-based: newborn screening, cancer screening) > Search first: CDC screening programs, USPSTF, cancer screening databases
  • Genetic screening (carrier screening, preimplantation genetic diagnosis, prenatal testing) > Search first: ACMG recommendations, ACOG guidelines, GTR
  • Risk stratification (identifying high-risk individuals for targeted prevention) > Search first: Risk prediction models, clinical calculators, PubMed
  • Behavioral Interventions: Lifestyle modifications to reduce risk

    Search first: CDC, WHO, behavioral intervention databases, Cochrane Library

  • Counseling: Genetic counseling (risk assessment, family planning guidance)

    Search first: NSGC resources, ACMG guidelines, GeneReviews

  • Public Health:
  • Public health interventions (sanitation, vector control, health education) > Search first: CDC, WHO, public health databases, PubMed
  • Environmental interventions (reducing environmental risk factors) > Search first: EPA databases, WHO environmental health, PubMed
  • Prophylaxis: Preventive medications or procedures

    Search first: Clinical guidelines, FDA approvals, PubMed

14. Other Species / Natural Disease

  • Taxonomy: Species affected (with NCBI Taxon identifiers)

    Search first: NCBI Taxonomy

  • Breed: Specific breeds affected (with VBO identifiers if applicable)

    Search first: VBO (Vertebrate Breed Ontology)

  • Gene: Orthologous genes in other species (with NCBI Gene IDs)

    Search first: NCBI Gene

  • Natural Disease:
  • Naturally occurring disease in other species (companion animals, wildlife) > Search first: OMIA (Online Mendelian Inheritance in Animals), VetCompass, PubMed
  • Veterinary relevance and importance in animal health > Search first: OMIA, veterinary databases, PubMed
  • Comparative Biology:
  • Comparative pathology (similarities and differences across species) > Search first: OMIA, comparative pathology databases, PubMed
  • Evolutionary conservation of disease mechanisms > Search first: HomoloGene, OrthoMCL, Alliance of Genome Resources
  • Transmission (if applicable):
  • Zoonotic potential > Search first: CDC zoonotic diseases, WHO zoonoses, GIDEON
  • Cross-species susceptibility > Search first: NCBI Taxonomy, veterinary databases, PubMed

15. Model Organisms

  • Model Types:
  • Model organism type (mammalian, invertebrate, cellular, in vitro) > Search first: Alliance of Genome Resources, model organism databases
  • Specific model systems (mouse, rat, zebrafish, Drosophila, C. elegans, yeast, cell lines, organoids, iPSCs) > Search first: MGI, RGD, ZFIN, FlyBase, WormBase, SGD, ATCC, Cellosaurus
  • Induced models (drug treatment, surgical intervention, environmental manipulation) > Search first: MGI, model organism databases, PubMed
  • Genetic Models:
  • Types available (knockout, knock-in, transgenic, conditional, humanized) > Search first: MGI, IMPC, KOMP, EuMMCR, IMSR
  • Model Characteristics:
  • Phenotype recapitulation (how well model reproduces human disease features) > Search first: Model organism databases, comparative studies, PubMed
  • Model limitations (aspects of human disease not captured) > Search first: Model organism databases, PubMed, review articles
  • Applications:
  • Research applications (what aspects of disease can be studied) > Search first: Model organism databases, PubMed
  • Resources:
  • Model databases > Search first: MGI, RGD, ZFIN, FlyBase, WormBase, IMSR, EMMA, MMRRC

Citation Requirements

  • Cite primary literature (PMID preferred) for all mechanistic and clinical claims
  • Prioritize recent reviews and landmark papers
  • Include direct quotes from abstracts where possible to support key statements
  • Distinguish evidence source types: human clinical, model organism, in vitro, computational

Output Format

Structure your response as a comprehensive narrative organized by the sections above. For each section, provide: - Factual content with specific details (numbers, percentages, gene names, variant nomenclature) - Ontology term suggestions (HPO, GO, CL, UBERON, CHEBI, MAXO, MONDO) where applicable - Evidence citations with PMIDs - Direct quotes from abstracts to support key claims - Clear indication when information is not available or not applicable for this disease

This report will be used to populate a disease knowledge base entry with: - Pathophysiology descriptions with causal chains - Gene/protein annotations (HGNC, GO terms) - Phenotype associations (HP terms) with frequencies - Cell type involvement (CL terms) - Anatomical locations (UBERON terms) - Chemical entities (CHEBI terms) - Treatment annotations (MAXO terms) - Evidence items with PMIDs and exact abstract quotes - Epidemiology, prognosis, diagnostic, and prevention information - Animal model descriptions with phenotype recapitulation details

Dyskeratosis Congenita (DC) — Comprehensive Disease Characteristics Report (Mendelian)

Target disease: Dyskeratosis congenita (DC)
Category: Mendelian / inherited bone marrow failure syndrome; telomere biology disorder (TBD) / short-telomere syndrome (niewisch2023clinicalmanifestationsof pages 1-2, rolles2024inheritedtelomerebiology pages 8-9).
MONDO ID: Not available in the retrieved full-text evidence in this run (mazurek2023dyskeratosiscongenitaas pages 4-5).

Executive summary

Dyskeratosis congenita is an ultra-rare inherited, multisystem disorder within the telomere biology disorders spectrum, classically defined by the mucocutaneous triad of nail dystrophy, abnormal/reticulated skin pigmentation, and oral leukoplakia, and complicated by progressive bone marrow failure and increased malignancy and fibrotic organ disease risk (koldej2023dyskeratosiscongenitanatural pages 1-2, rolles2024inheritedtelomerebiology pages 8-9, niewisch2023clinicalmanifestationsof pages 1-2). Contemporary understanding frames DC as a disorder of impaired telomere maintenance, in which germline pathogenic variants across telomerase, shelterin, CST/replication, and telomerase RNA processing/trafficking pathways cause telomere shortening/dysfunction leading to stem cell exhaustion and tissue failure (revy2023geneticsofhuman pages 5-8, rolles2024inheritedtelomerebiology pages 8-9, mazurek2023dyskeratosiscongenitaas pages 1-2).

A recent 2024 high-impact genetic study expanded DC’s genetic architecture (including a newly implicated X-linked gene POLA1 and expanded allelic series in POT1 and ZCCHC8) and emphasized that a substantial fraction of clinically diagnosed cases remain genetically unresolved (tummala2024theevolvinggenetic pages 1-2, tummala2024theevolvinggenetic pages 3-5).

Domain Summary
Identifiers/synonyms - Dyskeratosis congenita (DC) is also referred to as Zinsser–Cole–Engman syndrome in retrieved sources.
- It is classified as a telomere biology disorder (TBD) / short-telomere syndrome.
- Formal OMIM, Orphanet, ICD-10/11, MeSH, MONDO codes were not in retrieved full-text evidence. (ayas2026dyskeratosiscongenita pages 1-4, mazurek2023dyskeratosiscongenitaas pages 4-5, niewisch2023clinicalmanifestationsof pages 1-2)
Core definition - DC is an ultra-rare inherited multisystem bone marrow failure syndrome caused principally by defects in telomere maintenance.
- The classic diagnostic triad is nail dystrophy, abnormal/reticulated skin pigmentation, and oral leukoplakia.
- Bone marrow failure and cancer predisposition are central disease-defining complications. (koldej2023dyskeratosiscongenitanatural pages 1-2, tummala2024theevolvinggenetic pages 1-2, rolles2024inheritedtelomerebiology pages 8-9, niewisch2023clinicalmanifestationsof pages 1-2)
Key phenotypes & frequencies - Mucocutaneous triad frequencies reported in one 2023 review: reticulated pigmentation ~90%, nail dystrophy ~88%, leukoplakia ~80%.
- Bone marrow failure is a hallmark; some sources report >90% by age 40.
- Extra-hematologic disease includes pulmonary fibrosis/interstitial lung disease, liver disease/portal hypertension, premature hair graying, and cancer susceptibility; pulmonary fibrosis occurs in about 20% in one review. (mazurek2023dyskeratosiscongenitaas pages 4-5, ayas2026dyskeratosiscongenita pages 1-4, wang2021pulmonaryfibrosisin pages 1-2, vittal2023progressionofliver pages 1-2, franke2025diagnosisandmanagement pages 7-10)
Natural history stats - In a pediatric cohort (n=14), diagnosis occurred at median age 8.5 years; 13/14 progressed to bone marrow failure at median age 8 years.
- In the same cohort, 6/14 died, at median age 13 years; all had hematologic manifestations at diagnosis and non-hematologic manifestations accumulated over follow-up.
- Adult/cryptic TBD can present later with isolated hematologic, pulmonary, or liver disease rather than the full triad. (koldej2023dyskeratosiscongenitanatural pages 1-2, niewisch2023clinicalmanifestationsof pages 1-2, franke2025diagnosisandmanagement pages 7-10)
Key causal genes & new 2024 findings - Established genes in retrieved evidence include DKC1, TERC, TERT, TINF2, RTEL1, NOP10, NHP2, CTC1, ACD/TPP1, PARN, WRAP53/TCAB1, DCLRE1B, RPA1, NPM1, NAF1 and others; inheritance can be X-linked, autosomal dominant, or autosomal recessive.
- A 2024 EMBO Molecular Medicine study reported that about 35% of clinically diagnosed cases remain genetically unresolved and expanded the allelic architecture with POLA1 (novel X-linked gene), plus additional POT1 and ZCCHC8 variants.
- Functional data linked new variants to disrupted primase/CST/shelterin interactions, reduced POLA1 catalytic activity, reduced POT1 binding to telomeric ssDNA, and ZCCHC8 deficiency with pervasive transcription/inflammation. (tummala2024theevolvinggenetic pages 1-2, tummala2024theevolvinggenetic pages 3-5, niewisch2023clinicalmanifestationsof pages 1-2, rolles2024inheritedtelomerebiology pages 8-9)
Diagnostics (telomere length testing thresholds, screening yields) - Flow-FISH lymphocyte telomere length is the current preferred functional screening test; a commonly used threshold is <1st percentile for age for strong support of TBD/DC diagnosis.
- In adults, one 2023 prospective cohort used standard suspicion criteria of <10th percentile for age and an extended criterion of <6.5 kb in patients >40 years.
- In 262 screened adults, shortened TL was found in 120; among standard-screened patients with NGS material, 17/76 (22.4%) had pathogenic/likely pathogenic variants and 17/76 (22.4%) had VUS; main genes were TERT, TERC, RTEL1. (rolles2024inheritedtelomerebiology pages 8-9, tometten2023identificationofadult pages 1-2, tometten2023identificationofadult pages 6-7, tometten2023identificationofadult pages 3-4, niewisch2023clinicalmanifestationsof pages 5-5)
Treatments (androgens, HSCT, organ transplant considerations) - Androgens (especially danazol, also oxymetholone/nandrolone) can improve counts; reported hematologic response rates range about 50–100% short-term, with one study showing 11/12 patients gained telomere length (mean +386 bp) and 83% hematologic response at 24 months.
- HSCT/allo-HCT is the only curative therapy for marrow failure/clonal evolution, but transplant morbidity is substantial; reduced-intensity and radiation-avoiding approaches are favored, and related donors carrying the familial defect should be avoided.
- Organ transplantation (especially lung and liver) may be required for end-organ failure, but telomere disorders increase risk of hematologic and immunosuppression-related complications. (rolles2024inheritedtelomerebiology pages 12-14, ayas2026dyskeratosiscongenita pages 9-12, rolles2024inheritedtelomerebiology pages 10-12, glass2026telomerebiology pages 17-18)
Epidemiology - DC is consistently described as ultra-rare/rare.
- Retrieved prevalence estimates were approximately 1 case per 1,000,000 in one source and 1–9 per 1,000,000 in another review.
- One review noted marked male predominance in historical series (male:female ~13:1), though this may reflect enrichment of X-linked DKC1 disease in some cohorts. (koldej2023dyskeratosiscongenitanatural pages 1-2, mazurek2023dyskeratosiscongenitaas pages 4-5)

Table: This table condenses the most actionable facts on dyskeratosis congenita and related telomere biology disorders from the retrieved evidence, including definition, phenotype spectrum, genetics, diagnostics, treatment, and epidemiology. It is designed to support rapid knowledge-base curation with source-linked statements.


1. Disease information

1.1 What is the disease?

DC is an inherited multisystem telomere biology disorder characterized by the classic mucocutaneous triad and a high burden of bone marrow failure (BMF), with additional complications including pulmonary and liver disease and cancer predisposition (koldej2023dyskeratosiscongenitanatural pages 1-2, rolles2024inheritedtelomerebiology pages 8-9, niewisch2023clinicalmanifestationsof pages 1-2).

1.2 Key identifiers (ontology/coding)

In the retrieved full-text evidence available for this report, specific cross-references (OMIM, Orphanet, ICD-10/ICD-11, MeSH, MONDO) were not explicitly provided, so they cannot be populated with evidence-based values here (mazurek2023dyskeratosiscongenitaas pages 4-5).

1.3 Synonyms / alternative names

  • Zinsser–Cole–Engman syndrome (ayas2026dyskeratosiscongenita pages 1-4, mazurek2023dyskeratosiscongenitaas pages 4-5).
  • DC is also referenced as the archetypal/“classic” childhood-onset form within the broader telomere biology disorders spectrum (niewisch2023clinicalmanifestationsof pages 1-2, rolles2024inheritedtelomerebiology pages 8-9).

1.4 Evidence sources and aggregation level

The information in this report is derived primarily from: - Aggregated disease-level resources and reviews (e.g., ASH Education Program review 2023; Transfusion Medicine and Hemotherapy review 2024; Nature Reviews Genetics 2023) (niewisch2023clinicalmanifestationsof pages 1-2, rolles2024inheritedtelomerebiology pages 8-9, revy2023geneticsofhuman pages 5-8). - Cohort studies/natural history studies (e.g., pediatric cohort natural history 2023; liver involvement cohort 2023; adult screening cohort 2023) (koldej2023dyskeratosiscongenitanatural pages 1-2, vittal2023progressionofliver pages 1-2, tometten2023identificationofadult pages 1-2).


2. Etiology

2.1 Disease causal factors

Primary cause: Germline pathogenic variants affecting telomere maintenance (telomerase, shelterin, CST complex/replication, telomerase RNA processing/trafficking), producing critically short telomeres and telomere dysfunction (niewisch2023clinicalmanifestationsof pages 1-2, revy2023geneticsofhuman pages 5-8, rolles2024inheritedtelomerebiology pages 8-9).

Recent genetic expansion (2024): A large 2024 DC/DC-like study identified novel pathogenic variants and newly implicated the X-linked gene POLA1; it also expanded allelic series for POT1 and ZCCHC8, with functional work implicating disrupted interactions among primase, CST, and shelterin and inflammatory signatures from ZCCHC8 deficiency (tummala2024theevolvinggenetic pages 1-2, tummala2024theevolvinggenetic pages 3-5).

Direct abstract-supported quote (2024 EMBO Mol Med): the study “identify[ied]… novel pathogenic variants… and in the novel X-linked gene, POLA1” and reported functional impacts on “protein–protein interactions with primase, CST… and shelterin” (tummala2024theevolvinggenetic pages 1-2).

2.2 Risk factors

  • Genetic risk: Pathogenic variants across multiple telomere genes; incomplete penetrance/variable expressivity is characteristic of TBDs, especially adult-onset “cryptic” presentations (niewisch2023clinicalmanifestationsof pages 1-2, revy2023geneticsofhuman pages 5-8).
  • Genetic anticipation: Adult TBD reviews emphasize generational worsening linked to inheritance of short telomere reserve (tummala2024theevolvinggenetic pages 1-2, franke2025diagnosisandmanagement pages 7-10).

Environmental/clinical risk modifiers (organ progression): In a DC/TBD liver cohort, pulmonary and/or vascular disease predicted progression to clinically significant liver disease/portal hypertension, suggesting multisystem disease burden modifies organ risk (vittal2023progressionofliver pages 1-2).

2.3 Protective factors

No specific protective genetic variants or environmental protective factors were identified in the retrieved evidence.

2.4 Gene–environment interactions

Not specifically delineated for DC in the retrieved evidence; however, clinical cohorts support that systemic comorbidities (pulmonary/vascular disease) modify progression of liver complications (vittal2023progressionofliver pages 1-2).


3. Phenotypes

3.1 Core mucocutaneous triad (suggested HPO terms)

  • Nail dystrophy / nail dysplasia (HPO suggestion: HP:0001597). DC childhood-onset often includes nail changes (niewisch2023clinicalmanifestationsof pages 1-2, rolles2024inheritedtelomerebiology pages 8-9).
  • Abnormal/reticulated skin pigmentation (HPO suggestion: HP:0000994 or related terms for skin hyperpigmentation). Frequency estimates in one review: ~90% reticulated pigmentation (mazurek2023dyskeratosiscongenitaas pages 4-5).
  • Oral leukoplakia (HPO suggestion: HP:0002745). Frequency estimate: ~80% (mazurek2023dyskeratosiscongenitaas pages 4-5).

Triad frequency data (review-level): reticulated pigmentation ~90%, nail dystrophy ~88%, leukoplakia ~80% (mazurek2023dyskeratosiscongenitaas pages 4-5).

3.2 Hematologic phenotypes (suggested HPO terms)

  • Bone marrow failure / aplastic anemia (HPO: HP:0001915 / HP:0001917). BMF is a hallmark; one chapter reports BMF in >90% by age 40 (ayas2026dyskeratosiscongenita pages 1-4).
  • Cytopenias: thrombocytopenia (HPO: HP:0001873), neutropenia (HPO: HP:0001875), macrocytosis (HPO: HP:0000256), pancytopenia (HPO: HP:0001876) (definitions and use in a pediatric natural history cohort) (koldej2023dyskeratosiscongenitanatural pages 2-3, koldej2023dyskeratosiscongenitanatural pages 1-2).

Pediatric natural history: in a multicenter childhood-diagnosed cohort (n=14), all had hematologic manifestations at diagnosis; 13/14 progressed to BMF at median age 8 years (range 3–18) (koldej2023dyskeratosiscongenitanatural pages 1-2).

3.3 Pulmonary phenotypes (suggested HPO terms)

  • Interstitial lung disease / pulmonary fibrosis (HPO: HP:0006530 for pulmonary fibrosis). One review reports interstitial lung disease in ~20% of DC patients (franke2025diagnosisandmanagement pages 7-10). A systematic review/case synthesis also states ~20% develop pulmonary fibrosis (wang2021pulmonaryfibrosisin pages 1-2).

3.4 Liver phenotypes (suggested HPO terms)

  • Cholestatic liver enzyme elevation / liver abnormality (HPO suggestions may include abnormal liver function tests HP:0002910).
  • Portal hypertension (HPO: HP:0001405).

Cohort statistics (2023 Hepatology): In a DC/TBD cohort (n=58), baseline hepatic abnormality was 72.4% and 17.2% developed clinically significant liver disease/portal hypertension over follow-up (median 6 years) (vittal2023progressionofliver pages 1-2).

3.5 Cancer predisposition

DC/TBDs are associated with increased malignancy risk; head and neck squamous cell carcinoma is highlighted as a frequent solid tumor in DC/TBD contexts, and leukemia/MDS risks are emphasized in reviews/chapters (ayas2026dyskeratosiscongenita pages 1-4, niewisch2023clinicalmanifestationsof pages 1-2).

3.6 Quality of life (QoL)

Disease morbidity is described as high and multisystemic in longitudinal pediatric follow-up, but specific validated QoL instruments (e.g., SF-36, PROMIS) and quantitative QoL scores were not available in the retrieved evidence (koldej2023dyskeratosiscongenitanatural pages 1-2).


4. Genetic / molecular information

4.1 Causal genes (selected; non-exhaustive; HGNC symbols)

Authoritative 2023–2024 reviews and studies list DC/TBD genes spanning multiple telomere modules, including: - Telomerase core: TERT, TERC (revy2023geneticsofhuman pages 5-8, rolles2024inheritedtelomerebiology pages 8-9). - H/ACA RNP and telomerase RNA stability: DKC1, NHP2, NOP10, NAF1 (revy2023geneticsofhuman pages 5-8, niewisch2023clinicalmanifestationsof pages 1-2). - Telomerase trafficking/recruitment: WRAP53/TCAB1 and related factors (niewisch2023clinicalmanifestationsof pages 1-2, rolles2024inheritedtelomerebiology pages 8-9). - Shelterin / end protection: TINF2, POT1, ACD (TPP1) (niewisch2023clinicalmanifestationsof pages 1-2, tummala2024theevolvinggenetic pages 3-5). - Replication/CST axis: CTC1 (and CST complex context), with emerging evidence that CST–Polα/primase interactions are critical (tummala2024theevolvinggenetic pages 3-5, mazurek2023dyskeratosiscongenitaas pages 1-2). - RNA processing / additional implicated loci: PARN, ZCCHC8 (tummala2024theevolvinggenetic pages 1-2, revy2023geneticsofhuman pages 5-8).

4.2 Variant classes and functional consequences

In the 2024 EMBO Molecular Medicine cohort, variant types included predominantly missense and loss-of-function categories, plus deletions/insertions (tummala2024theevolvinggenetic pages 1-2).

Mechanistic consequences from reviews include: - Impaired telomerase activity/processivity/recruitment (TERT/TERC and recruitment factors) (niewisch2023clinicalmanifestationsof pages 1-2, revy2023geneticsofhuman pages 5-8). - Reduced telomerase RNA stability/maturation (DKC1/NHP2/NOP10 axis) (revy2023geneticsofhuman pages 5-8, niewisch2023clinicalmanifestationsof pages 1-2).

4.3 Newly implicated genes/alleles (2024)

A 2024 DC/DC-like study: - Reported a novel X-linked gene POLA1 with functionally validated disease alleles and skewed X-inactivation in carrier mothers (tummala2024theevolvinggenetic pages 3-5). - Expanded the allelic series of POT1 with demonstrated reduced binding to telomeric ssDNA for pathogenic variants (tummala2024theevolvinggenetic pages 3-5). - Expanded ZCCHC8 variants associated with deficiency and inflammatory/transcriptional dysregulation signatures in blood (tummala2024theevolvinggenetic pages 1-2).

4.4 Modifier genes / polygenic background

The retrieved corpus includes evidence that incomplete penetrance/variable expressivity is common in TBDs and that broader genetic context contributes to variability; specific DC-focused protective modifiers were not identified in the retrieved evidence (niewisch2023clinicalmanifestationsof pages 1-2, revy2023geneticsofhuman pages 5-8).


5. Environmental information

No specific toxins, lifestyle exposures, or infectious triggers were identified as primary causal factors for DC in the retrieved evidence. Clinical guidance emphasizes the need to recognize DC/TBD prior to potentially harmful treatments (e.g., immunosuppression in fibrotic lung disease contexts) (wang2021pulmonaryfibrosisin pages 1-2).


6. Mechanism / pathophysiology

6.1 Current mechanistic model (upstream → downstream chain)

  1. Upstream trigger: germline defects in telomere maintenance genes (telomerase, shelterin, CST, RNA processing/trafficking) (rolles2024inheritedtelomerebiology pages 8-9, revy2023geneticsofhuman pages 5-8).
  2. Molecular consequence: accelerated telomere shortening and/or telomere dysfunction (very short telomeres are characteristic; diagnostic thresholds often involve <1st percentile for age) (koldej2023dyskeratosiscongenitanatural pages 1-2, rolles2024inheritedtelomerebiology pages 8-9).
  3. Cellular consequence: activation of DNA damage responses leading to senescence and/or apoptosis, limiting replicative potential of high-turnover tissues (hematopoietic/immune/epithelial compartments) (niewisch2023clinicalmanifestationsof pages 1-2, glass2026telomerebiology pages 1-5).
  4. Tissue consequence: stem cell depletion and organ failure phenotypes: bone marrow failure, pulmonary/liver fibrosis; genomic instability contributes to cancer predisposition (ayas2026dyskeratosiscongenita pages 1-4, vittal2023progressionofliver pages 1-2).

6.2 Pathways and processes (suggested GO terms)

Suggested GO Biological Process terms consistent with the evidence: - Telomere maintenance (GO:0000723) - DNA damage response, signal transduction by p53 class mediator (GO:0030330) - Cellular senescence (GO:0090398) - Apoptotic process (GO:0006915) - Hematopoietic stem cell differentiation / hematopoiesis (e.g., GO:0030097)

6.3 Cell types involved (suggested CL terms)

  • Hematopoietic stem cell (CL:0000037)
  • Hematopoietic progenitor cell (CL:0008001)
  • T cell / lymphocyte (for telomere length assays and immune involvement) (rolles2024inheritedtelomerebiology pages 8-9, niewisch2023clinicalmanifestationsof pages 5-5)
  • Alveolar type II cell (pulmonary fibrosis context; suggested CL:0002063) (carlier2026hematologicalcomplicationsin pages 2-3)

6.4 Mechanistic evidence from model systems

A CRISPR Ten1 knockout mouse (TEN1; CST complex) provides a DC-like in vivo model: Ten1 deficiency caused telomere shortening, short lifespan, aplastic anemia, skin hyperpigmentation, and broad organ pathology with activation of p53/p21 signaling and evidence of reduced proliferation and increased apoptosis (sanzmoreno2025lossoften1 pages 1-2, sanzmoreno2025lossoften1 pages 3-6, sanzmoreno2025lossoften1 pages 2-3). This supports a causal mechanistic route from CST dysfunction → telomere attrition → p53-mediated tissue failure.


7. Anatomical structures affected

7.1 Organ level (suggested UBERON terms)

  • Bone marrow (UBERON:0002371) and hematopoietic system (BMF) (ayas2026dyskeratosiscongenita pages 1-4, koldej2023dyskeratosiscongenitanatural pages 1-2).
  • Lung (UBERON:0002048) (pulmonary fibrosis/ILD) (franke2025diagnosisandmanagement pages 7-10, wang2021pulmonaryfibrosisin pages 1-2).
  • Liver (UBERON:0002107) (cholestatic abnormalities, portal hypertension) (vittal2023progressionofliver pages 1-2).
  • Skin (UBERON:0002097) and mucosa/oral cavity (leukoplakia) (rolles2024inheritedtelomerebiology pages 8-9, mazurek2023dyskeratosiscongenitaas pages 4-5).

7.2 Tissue and cell level

  • High-turnover tissues are emphasized as vulnerable to low telomere reserve, including hematopoietic and immune compartments; liver and lung involvement is prominent in DC/TBD cohorts (rolles2024inheritedtelomerebiology pages 8-9, vittal2023progressionofliver pages 1-2).

7.3 Subcellular localization (suggested GO cellular component)

  • Telomere (GO:0000781)
  • Cajal body (for WRAP53/TCAB1 biology; relevant to telomerase trafficking) (niewisch2023clinicalmanifestationsof pages 1-2)

8. Temporal development

8.1 Onset

  • Classic DC often manifests in childhood with mucocutaneous features, while “cryptic” TBD/DC may present in adulthood with isolated marrow, lung, liver disease, or cancer (niewisch2023clinicalmanifestationsof pages 1-2, franke2025diagnosisandmanagement pages 7-10).

8.2 Progression

  • Pediatric cohort: progressive accumulation of non-hematologic complications; high early hematologic morbidity with frequent progression to BMF and childhood/young-adult mortality (koldej2023dyskeratosiscongenitanatural pages 1-2).
  • Liver cohort: baseline liver abnormalities common; subset progresses to portal hypertension over years of follow-up (vittal2023progressionofliver pages 1-2).

9. Inheritance and population

9.1 Epidemiology

  • Prevalence estimate reported as ~1 per 1,000,000 in one source (koldej2023dyskeratosiscongenitanatural pages 1-2).
  • Another review reports 1–9 per 1,000,000 (mazurek2023dyskeratosiscongenitaas pages 4-5).

9.2 Inheritance patterns

DC/TBDs show all Mendelian modes: - X-linked recessive, autosomal dominant, and autosomal recessive inheritance (niewisch2023clinicalmanifestationsof pages 1-2, tummala2024theevolvinggenetic pages 1-2).

9.3 Demographics

A review reports strong male predominance (male:female ~13:1), likely reflecting enrichment of X-linked disease in some series; population-level sex ratio remains uncertain from the retrieved evidence (mazurek2023dyskeratosiscongenitaas pages 4-5).

Data gaps (not in retrieved evidence): incidence rates, carrier frequency, geographic/ancestry founder effects.


10. Diagnostics

10.1 Clinical criteria (core recognition)

  • The classic triad (nail dystrophy, skin pigmentation abnormalities, oral leukoplakia) plus hematologic and multisystem findings supports clinical suspicion (rolles2024inheritedtelomerebiology pages 8-9, niewisch2023clinicalmanifestationsof pages 1-2).

10.2 Telomere length testing (real-world implementation)

Preferred functional test: Flow-FISH telomere length measurement in leukocyte subsets; lymphocyte telomere length is described as sensitive and highly specific (rolles2024inheritedtelomerebiology pages 8-9).
Common diagnostic threshold: lymphocyte telomere length <1st percentile for age by flow-FISH strongly supports TBD/DC (rolles2024inheritedtelomerebiology pages 8-9).

Adult screening algorithm and yield (2023 prospective cohort): - Standard suspicion: <10th percentile for age; extended adult criterion: <6.5 kb in patients >40 years (tometten2023identificationofadult pages 1-2, tometten2023identificationofadult pages 3-4). - In 262 referred adults screened by flow-FISH, 120 had shortened telomeres; among standard-screened patients with NGS material, 17/76 (22.4%) had pathogenic/likely pathogenic variants and 17/76 (22.4%) had VUS (tometten2023identificationofadult pages 1-2).

10.3 Genetic testing strategy

Recent diagnostic pathways recommend: - Telomere length testing as prescreen, followed by targeted NGS panels and, if unresolved, WES/WGS focused on telomere maintenance genes (rolles2024inheritedtelomerebiology pages 10-12). - Recognition that a pathogenic variant is not found in all clinical cases (e.g., ~20% without identifiable cause in one review; ~35% unresolved in a 2024 DC cohort) (niewisch2023clinicalmanifestationsof pages 5-5, tummala2024theevolvinggenetic pages 1-2).

10.4 Differential diagnosis

  • Acquired aplastic anemia vs inherited marrow failure/TBD: telomere testing helps discriminate; evaluation may include Fanconi anemia chromosome breakage testing when relevant (koldej2023dyskeratosiscongenitanatural pages 2-3, NCT01659606 chunk 2).

11. Outcome / prognosis

11.1 Survival and mortality (recent cohort data)

In a Spanish pediatric DC cohort (n=14): - Median diagnosis age 8.5 years; 13 progressed to bone marrow failure at median age 8 years. - 6/14 died at median age 13 years (range 6–24) (koldej2023dyskeratosiscongenitanatural pages 1-2).

11.2 Major morbidity drivers and statistics

  • Bone marrow failure: reported in >90% by age 40 in a DC chapter (ayas2026dyskeratosiscongenita pages 1-4).
  • Liver disease: baseline abnormality 72.4%; 17.2% progressed to portal hypertension (vittal2023progressionofliver pages 1-2).
  • Pulmonary fibrosis/ILD: ~20% reported in reviews (franke2025diagnosisandmanagement pages 7-10, wang2021pulmonaryfibrosisin pages 1-2).

11.3 Prognostic factors

  • Liver progression risk enriched in recessive or TINF2-associated DC and predicted by concurrent pulmonary/vascular disease (vittal2023progressionofliver pages 1-2).
  • Pulmonary fibrosis systematic review suggests genotype–phenotype correlations (e.g., later ages in TERC/TERT; differences in survival by gene class), and warns against immunosuppression or lung biopsy in unrecognized DC-associated PF (wang2021pulmonaryfibrosisin pages 1-2).

12. Treatment

12.1 Pharmacotherapy — androgens

Danazol and other androgens are used as non-transplant therapies for TBD/DC-related marrow failure. - A 2024 review summarizes androgen response evidence: oxymetholone hematologic responses around 69% with frequent adverse effects; danazol with fewer side effects and reported hematologic responses (some studies ~83% at 24 months) and telomere length gains in a subset (e.g., 11/12 gained TL; mean +386 bp) (rolles2024inheritedtelomerebiology pages 12-14). - A DC chapter also reports observational hematologic response ~70% and prospective danazol trial response ~80%, while noting toxicity (liver enzyme elevation, virilization) and discontinuation risk (ayas2026dyskeratosiscongenita pages 4-7).

MAXO suggestions: androgen therapy (e.g., MAXO:0000058 pharmacotherapy; more specific term depends on MAXO mapping availability).

12.2 Hematopoietic stem cell transplantation (HSCT)

HSCT is described as the only curative therapy for DC marrow failure/clonal evolution, but outcomes are complicated by multisystem fragility (ayas2026dyskeratosiscongenita pages 9-12).

Key implementation considerations: - Avoid related donors with the same pathogenic variant when possible (risk of graft failure and adverse outcomes) (rolles2024inheritedtelomerebiology pages 10-12). - Avoid radiation in conditioning when possible because of late pulmonary toxicity and secondary malignancy concerns (ayas2026dyskeratosiscongenita pages 9-12).

ClinicalTrials.gov implementation example: A radiation- and alkylator-free HSCT regimen trial (NCT01659606) specifies conditioning with alemtuzumab and fludarabine and post-transplant immunosuppression options (mycophenolate plus cyclosporine or tacrolimus), with eligibility including DC and related syndromes (NCT01659606 chunk 2).

MAXO suggestions: hematopoietic stem cell transplantation (MAXO:0000747), reduced-intensity conditioning (MAXO term depends on available hierarchy).

12.3 Solid organ transplantation

For end-stage lung or liver disease, transplantation may be required; reviews emphasize higher complication risk and the need for careful pre-transplant TBD recognition (glass2026telomerebiology pages 17-18).

12.4 Experimental/clinical trials landscape (selected, based on retrieved trial records)

  • Danazol trial: NCT01441037 (“Danazol for Genetic Bone Marrow and Lung Disorders”) targets aplastic anemia/pulmonary fibrosis/liver cirrhosis phenotypes, includes pediatric patients (min age 2 years), and cites a related NEJM publication (NCT01441037 chunk 2).
  • HSCT trials: NCT02162420 includes transplant conditioning agents (alemtuzumab/fludarabine/cyclophosphamide/TBI, thymoglobulin) and includes “Secondary malignancies” as an outcome (NCT02162420 chunk 2).

Data gap: For some NCT records, phase/enrollment/status fields were not present in the retrieved text chunks; therefore they are not reported with evidence here (NCT01441037 chunk 2, NCT02162420 chunk 2).


13. Prevention

Primary prevention of genetic DC is not generally applicable beyond reproductive options; retrieved evidence emphasizes surveillance and avoidance of harmful interventions once disease is suspected/diagnosed. - For DC-associated pulmonary fibrosis, the systematic review warns against empiric immunosuppression and diagnostic surgical lung biopsy before excluding DC/TBD (wang2021pulmonaryfibrosisin pages 1-2).

MAXO suggestions: genetic counseling (MAXO term), surveillance program (MAXO term).


14. Other species / natural disease

No naturally occurring veterinary DC analogs were identified in the retrieved evidence.


15. Model organisms

15.1 Mammalian model (mouse)

A Ten1 (CST complex) CRISPR knockout mouse is described as a model of DC/TBD: - Phenotypes: telomere attrition, short lifespan, skin hyperpigmentation, aplastic anemia/BMF, cerebellar hypoplasia, and multi-organ pathology (sanzmoreno2025lossoften1 pages 1-2, sanzmoreno2025lossoften1 pages 2-3). - Mechanism: reduced proliferation, increased apoptosis, stem cell depletion, and activation of p53/p21 signaling (sanzmoreno2025lossoften1 pages 1-2, sanzmoreno2025lossoften1 pages 3-6).

15.2 Cellular/ex vivo models

Reviews describe use of CD34+ HSPCs and variant cell models (e.g., DKC1 variant cells), including therapeutic strategy exploration via PAPD5/7 inhibition restoring telomere length/TERC levels in specific contexts (franke2025diagnosisandmanagement pages 15-17, revy2023geneticsofhuman pages 27-30).


Notes on evidence gaps in this run

  • Ontology IDs (OMIM/Orphanet/MeSH/ICD/MONDO) were not directly present in retrieved full texts; they should be populated by querying OMIM/Orphanet/MONDO directly in a follow-on curation step.
  • QoL metrics and standardized diagnostic criteria statements (beyond telomere testing thresholds and clinical triad) were limited in retrieved evidence.

Key recent sources prioritized (2023–2024)

  • Tummala et al., EMBO Molecular Medicine, Aug 2024, “The evolving genetic landscape of telomere biology disorder dyskeratosis congenita.” https://doi.org/10.1038/s44321-024-00118-x (tummala2024theevolvinggenetic pages 1-2, tummala2024theevolvinggenetic pages 3-5)
  • Rolles et al., Transfusion Medicine and Hemotherapy, Jul 2024, “Inherited Telomere Biology Disorders: Pathophysiology, Clinical Presentation, Diagnostics, and Treatment.” https://doi.org/10.1159/000540109 (rolles2024inheritedtelomerebiology pages 8-9, rolles2024inheritedtelomerebiology pages 12-14)
  • Niewisch et al., ASH Education Program, Dec 2023, “Clinical manifestations of telomere biology disorders in adults.” https://doi.org/10.1182/hematology.2023000490 (niewisch2023clinicalmanifestationsof pages 1-2, niewisch2023clinicalmanifestationsof pages 5-5)
  • Tometten et al., HemaSphere, Apr 2023, adult flow-FISH screening cohort. https://doi.org/10.1097/hs9.0000000000000874 (tometten2023identificationofadult pages 1-2, tometten2023identificationofadult pages 3-4)
  • Vittal et al., Hepatology, May 2023, liver disease progression. https://doi.org/10.1097/hep.0000000000000461 (vittal2023progressionofliver pages 1-2)
  • Koldej et al., Frontiers in Pediatrics, Aug 2023, pediatric natural history cohort. https://doi.org/10.3389/fped.2023.1182476 (koldej2023dyskeratosiscongenitanatural pages 1-2)

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