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Dyskeratosis congenita (DC) is a rare inherited bone marrow failure syndrome, caused by genetic mutations that principally affect telomere biology. Approximately 35% of cases remain uncharacterised at the genetic level. To explore the genetic landscape, we conducted genetic studies on a large collection of clinically diagnosed cases of DC as well as cases exhibiting features resembling DC, referred to as 'DC-like' (DCL). This led us to identify several novel pathogenic variants within known genetic loci and in the novel X-linked gene, POLA1. In addition, 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. 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. ZCCHC8 variants demonstrated ZCCHC8 deficiency and signs of pervasive transcription, triggering inflammation in patients' blood. In conclusion, our studies expand the current genetic architecture and broaden our understanding of disease mechanisms underlying DC and DCL disorders. Synopsis: The evolving genetic landscape of inherited bone marrow failure syndrome dyskeratosis congenita reveals new pathogenic variants that broadens our understanding of current genetic and molecular mechanisms underlying this disorder. Several novel pathogenic variants within known susceptibility loci, as well as in the novel X-linked locus POLA1, are part of the evolving DC and DCL genetic landscape. Telomere maintenance is impacted by novel variants in POLA1 and POT1, while pervasive transcription and inflammation are caused by ZCCHC8 variants. Current knowledge on disease mechanisms beyond the regulation of long non-coding RNA TERC is extended by the clinical, genetic, and molecular similarity between DC and DCL cases. The evolving genetic landscape of inherited bone marrow failure syndrome dyskeratosis congenita reveals new pathogenic variants that broadens our understanding of current genetic and molecular mechanisms underlying this disorder. [ABSTRACT FROM AUTHOR]

ABSTRACT Dyskeratosis congenita (DC) is a rare inherited bone marrow disease that classically presents with the triad of oral leukoplakia, nail dystrophy, and reticular hyperpigmentation. It is most commonly caused by a defect in the DKC1 gene involved in telomere stability. Malignant progression of oral leukoplakia to squamous cell carcinoma (SCC) is rare in DC, especially in younger patients, and cutaneous SCC is only reported in 1.5% of cases of DC. Here we report a case of a 12‐year‐old female with a familial heterozygous RTEL1 (regulator of telomere elongation helicase 1) gene mutation associated with a severe phenotype of DC characterized by multiple cutaneous SCCs. [ABSTRACT FROM AUTHOR]

Background: Dyskeratosis congenita (DKC), also known as Zinsser–Cole–Engman syndrome, is a progressive genetic disease with a triad of reticulate skin pigmentation, nail dystrophy, and leukoplakia. Approximately 8–10% of patients with DKC develop malignancies, and cases of colorectal cancer with DKC in young people have been reported previously. Case presentation: A 25-year-old man with DKC since approximately 10 years of age developed fever and lower abdominal discomfort. Diagnostic imaging revealed locally advanced rectal cancer with lymph node metastasis, direct invasion of the prostate, and pelvic abscess due to tumor microperforation (cT4bN2M0 cStage IIIC). Biopsy showed well to moderately differentiated ductal adenocarcinoma. Genetic testing was negative for RAS and BRAF gene mutations, and microsatellite instability (MSI) testing was also negative. After sigmoid colostomy, the patient was treated with total neoadjuvant therapy (TNT) with systemic chemotherapy (six courses of FOLFOX + panitumumab) followed by chemoradiation therapy (50.4 Gy with capecitabine). After TNT, the primary tumor and metastatic lymph nodes shrank. According to the findings of colonoscopy and magnetic resonance image (MRI), we diagnosed near complete response (near-CR) and decided to follow the patient without surgery by every 3 months re-evaluation. However, 5 months after TNT, tumor regrowth was detected on colonoscopy and imaging, and the patient underwent total pelvic exenteration. He developed paralytic ileus as a postoperative complication, and was discharged on the 38th postoperative day. Pathological examination revealed a residual tumor with invasion of the periprostatic tissue. There was no metastasis in the pararectal and lateral pelvic lymph nodes, but one extramural non-contiguous cancerous extension (tumor deposit) was observed (ypT4bN1cM0 ypStage IIIC). The patient has been free of recurrence for one year after surgery. Conclusions: DKC often develops into various tumors in the digestive system at an early age; therefore, appropriate surveillance may be required. In addition, considering that cancers in patients with DKC occur at a young age, fertility preservation and survivorship are also important, and adequate explanations and care should be provided to patients before and after treatment. [ABSTRACT FROM AUTHOR]

Telomere biology disorders (TBD) are a complex set of inherited illnesses characterized by short telomeres. Dyskeratosis congenita (DC), which is now considered a severe TBD phenotype, is characterized by reticulated pigmentary changes, nail dystrophy, premalignant oral leukoplakia, and systemic involvement. This case describes a 2‐year‐old female with reticulated pigmentary changes and Terry's nails who was found to have a TERT variant and short telomeres; she lacked other mucocutaneous and systemic features of TBD. This report describes a unique clinical presentation of TBD and highlights the importance of upholding suspicion for TBD in individuals with limited or subtle features of classic DC. [ABSTRACT FROM AUTHOR]

Background: Telomeres are the end-capping structures of all eukaryotic chromosomes thereby protecting the genome from damage and degradation. During the aging process, telomeres shorten continuously with each cell division until critically short telomeres prevent further proliferation whereby cells undergo terminal differentiation, senescence, or apoptosis. Premature aging due to critically short telomere length (TL) can also result from pathogenic germline variants in the telomerase complex or related genes that typically counteract replicative telomere shortening in germline and certain somatic cell populations, e.g., hematopoetic stem cells. Inherited diseases that result in altered telomere maintenance are summarized under the term telomere biology disorder (TBD). Summary: Since TL both reflects but more importantly restricts the replicative capacity of various human tissues, a sufficient telomere reserve is particularly important in cells with high proliferative activity (e.g., hematopoiesis, immune cells, intestinal cells, liver, lung, and skin). Consequently, 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. Key Messages: The recognition of a potential congenital origin in approximately 10% of adult patients with clinical BMF is of utmost importance for the proper diagnosis, appropriate patient and family counseling, to prevent the use of inefficient treatment and to avoid therapy-related toxicities including appropriate donor selection when patients have to undergo stem cell transplantation from related donors. This review summarizes the current state of knowledge about TBDs with particular focus on the clinical manifestation patterns in children (termed early onset TBD) compared to adults (late-onset TBD) including typical treatment- and disease course-related complications as well as their prognosis and adequate therapy. Thereby, it aims to raise awareness for a disease group that is currently still highly underdiagnosed particularly when it first manifests itself in adulthood. [ABSTRACT FROM AUTHOR]

Dyskeratosis congenita (DC) is a telomeropathy presenting diagnostic and therapeutic challenges across multiple specialties; yet, subtle dermatological signs enable early detection, altering patient prognosis. A specific DC genetic sequencing was performed according to the clinical criteria of our patient in study. Subsequently, cross-checked information in the main genetic databases was carried out. Additionally, an extensive review of the literature was made to organize the main dermatological aspects in DC. We report a novel variant of DC. Additionally, we share 10 useful and practical messages for dermatologists and any specialist caring for this group of patients. [ABSTRACT FROM AUTHOR]

Abstract Dyskeratosis congenita (DC) is a rare inherited bone marrow failure syndrome, caused by genetic mutations that principally affect telomere biology. Approximately 35% of cases remain uncharacterised at the genetic level. To explore the genetic landscape, we conducted genetic studies on a large collection of clinically diagnosed cases of DC as well as cases exhibiting features resembling DC, referred to as ‘DC-like’ (DCL). This led us to identify several novel pathogenic variants within known genetic loci and in the novel X-linked gene, POLA1. In addition, 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. 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. ZCCHC8 variants demonstrated ZCCHC8 deficiency and signs of pervasive transcription, triggering inflammation in patients’ blood. In conclusion, our studies expand the current genetic architecture and broaden our understanding of disease mechanisms underlying DC and DCL disorders.

Fanconi anemia (FA), dyskeratosis congenita-related telomere biology disorders (DC/TBD), and Diamond–Blackfan anemia (DBA) are inherited bone marrow failure syndromes (IBMFS) with high risks of bone marrow failure, leukemia, and solid tumors. Individuals with FA have reduced fertility. Previously, we showed low levels of anti-Müllerian hormone (AMH), a circulating marker of ovarian reserve, in females with IBMFS. In males, AMH may be a direct marker of Sertoli cell function and an indirect marker of spermatogenesis. In this study, we assessed serum AMH levels in pubertal and postpubertal males with FA, DC/TBD, or DBA and compared this with their unaffected male relatives and unrelated healthy male volunteers. Males with FA had significantly lower levels of AMH (median: 5 ng/mL, range: 1.18–6.75) compared with unaffected male relatives (median: 7.31 ng/mL, range: 3.46–18.82, P = 0.03) or healthy male volunteers (median: 7.66 ng/mL, range: 3.3–14.67, P = 0.008). Males with DC/TBD had lower levels of AMH (median: 3.76 ng/mL, range: 0–8.9) compared with unaffected relatives (median: 5.31 ng/mL, range: 1.2–17.77, P = 0.01) or healthy volunteers (median: 5.995 ng/mL, range: 1.57–14.67, P < 0.001). Males with DBA had similar levels of AMH (median: 3.46 ng/mL, range: 2.32–11.85) as unaffected relatives (median: 4.66 ng/mL, range: 0.09–13.51, P = 0.56) and healthy volunteers (median: 5.81 ng/mL, range: 1.57–14.67, P = 0.10). Our findings suggest a defect in the production of AMH in postpubertal males with FA and DC/TBD, similar to that observed in females. These findings warrant confirmation in larger prospective studies.

Introduction: Dyskeratosis congenita is a rare genetic disorder characterized by abnormalities of the skin, nails, and oral mucosa. Retinal involvement in this condition is uncommon. Here, we present a case of a young male patient diagnosed with presumptive cytomegalovirus retinitis, ultimately found to be concomitant with dyskeratosis congenita. Case Presentation: A non-HIV-infected young male with recurrent infections, including aspergillus pneumonia and pneumocystis pneumonia, presented with presumptive cytomegalovirus retinitis in both eyes. Systemic manifestations included cutaneous hyperpigmentation, nail dystrophy, and oral mucosal leukoplakia. Genetic testing revealed a mutation in the DKC1 gene. The final diagnosis was dyskeratosis congenita complicated by presumptive cytomegalovirus retinitis. Conclusion: Cytomegalovirus retinitis can serve as an ocular complication of dyskeratosis congenita. When a patient presents with cytomegalovirus retinitis, a comprehensive systematic examination should be conducted as it indicates severe immunodeficiency.

Introduction: Dyskeratosis congenita is a rare genetic disorder characterized by abnormalities of the skin, nails, and oral mucosa. Retinal involvement in this condition is uncommon. Here, we present a case of a young male patient diagnosed with presumptive cytomegalovirus retinitis, ultimately found to be concomitant with dyskeratosis congenita. Case Presentation: A non-HIV-infected young male with recurrent infections, including aspergillus pneumonia and pneumocystis pneumonia, presented with presumptive cytomegalovirus retinitis in both eyes. Systemic manifestations included cutaneous hyperpigmentation, nail dystrophy, and oral mucosal leukoplakia. Genetic testing revealed a mutation in the DKC1 gene. The final diagnosis was dyskeratosis congenita complicated by presumptive cytomegalovirus retinitis. Conclusion: Cytomegalovirus retinitis can serve as an ocular complication of dyskeratosis congenita. When a patient presents with cytomegalovirus retinitis, a comprehensive systematic examination should be conducted as it indicates severe immunodeficiency. [ABSTRACT FROM AUTHOR]

Dyskeratosis congenita (DKC) is a rare genetic disorder characterized by lacy reticular skin hyperpigmentation, bone marrow failure, nail dystrophy, and oral leukoplakia. To the best of our knowledge, only around 200 cases were reported in the medical literature, and in this report, we present another distinctive case from Syria. This case report describes a male patient with generalized reticular pigmentation and abnormal nails since childhood. The patient reported a history of recurrent urethral stenosis and corneal density. Dermoscopic examination revealed pigmented lines arranged in a netlike pattern. Histopathological findings were nonspecific. Hematological values were unremarkable. A contrast CT scan revealed changes in the bladder wall. The final diagnosis of Dyskeratosis Congenita was made based on the clinical criteria. This disorder can present with additional cutaneous manifestations and systemic complications. Treatment are generally prescribed to maintain bone marrow function, based on the fact that it is the major cause of death. Regular monitoring and screening for associated conditions are recommended. [ABSTRACT FROM AUTHOR]

Telomeres are the nucleoprotein complex at chromosome ends essential in genomic stability. Baseline telomere length (TL) is determined by rare and common germline genetic variants but shortens with age and is susceptible to certain environmental exposures. Cellular senescence or apoptosis are normally triggered when telomeres reach a critically short length, but cancer cells overcome these protective mechanisms and continue to divide despite chromosomal instability. Rare germline variants in telomere maintenance genes cause exceedingly short telomeres for age (< 1st percentile) and the telomere biology disorders, which are associated with elevated risks of bone marrow failure, myelodysplastic syndrome, acute myeloid leukemia, and squamous cell carcinoma of the head/neck and anogenital regions. Long telomeres due to rare germline variants in the same or different telomere maintenance genes are associated with elevated risks of other cancers, such as chronic lymphocytic leukemia or sarcoma. Early epidemiology studies of TL in the general population lacked reproducibility but new methods, including creation of a TL polygenic score using common variants, have found longer telomeres associated with excess risks of renal cell carcinoma, glioma, lung cancer, and others. It has become clear that when it comes to TL and cancer etiology, not too short, not too long, but "just right" telomeres are important in minimizing cancer risk. [ABSTRACT FROM AUTHOR]

Introduction: The inherited bone marrow failure syndromes (IBMFSs) are a group of rare disorders characterized by bone marrow failure (BMF), physical abnormalities, and an increased risk of neoplasia. The National Institute of Pediatrics (INP) is a major medical institution in Mexico, where patients with BMF receive a complete approach that includes paraclinical tests. Readily recognizable features, such as the hematological and distinctive physical phenotypes, identified by clinical dysmorphologists, remain crucial for the diagnosis and management of these patients, particularly in circumstances where next-generation sequencing (NGS) is not easily available. Here, we describe a group of Mexican patients with a high clinical suspicion of an IBMFS. Methods: We performed a systematic retrospective analysis of the medical records of patients who had a high IBMFS suspicion at our institution from January 2018 to July 2021. An initial assessment included first ruling out acquired causes of BMF by the Hematology Department and referral of the patient to the Department of Human Genetics for physical examination to search for specific phenotypes suggesting an IBMFS. Patients with high suspicion of having an IBMFS were classified into two main groups: 1) specific IBMFS, including dyskeratosis congenita (DC), Diamond-Blackfan anemia (DBA), Shwachman-Diamond syndrome (SDS), thrombocytopenia with absent radii (TAR), and severe congenital neutropenia (SCN); 2) undefined IBMFS (UI). Results: We established a high suspicion of having an IBMFS in 48 patients. At initial evaluation, the most common hematologic features were bicytopenia (20%) and aplastic anemia (16%); three patients received hematopoietic stem cell transplantation. Among patients with a suspicion of an IBMFS, the most common physical abnormality was minor craniofacial features in 83% of patients and neurodevelopmental disorders in 52%. The specific suspicions that we built were DBA (31%), SDS (18%), DC (14%), TAR (4%), and SCN (4%), whereas 27% of cases remained as undefined IBMFS. SDS, TAR, and SCN were more commonly suspected at an earlier age (<1 year), followed by DBA (2 years) and DC (5 years). Conclusions: Thorough examination of reported clinical data allowed us to highly suspect a specific IBMFS in approximately 70% of patients; however, an important number of patients remained with suspicion of an undefined IBMFS. Implementation of NGS and telomere length measurement are forthcoming measures to improve IBMFS diagnosis in Mexico. [ABSTRACT FROM AUTHOR]

Dyskeratosis Congenita (DC) is a multisystem disorder intrinsically associated with telomere dysfunction, leading to bone marrow failure (BMF). Although the pathology of DC is largely driven by mutations in telomere-associated genes, the implications of gene fusions, which emerge due to telomere-induced genomic instability, remain unexplored. We meticulously analyzed gene fusions in RNA-Seq data from DC patients to provide deeper insights into DC's progression. The most significant DC-specific gene fusions were subsequently put through in silico assessments to ascertain biophysical and structural attributes, including charge patterning, inherent disorder, and propensity for self-association. Selected candidates were then analyzed using deep learning-powered structural predictions and molecular dynamics simulations to gauge their potential for forming higher-order oligomers. Our exploration revealed that genes participating in fusion events play crucial roles in upholding genomic stability, facilitating hematopoiesis, and suppressing tumors. Notably, our analysis spotlighted a particularly disordered polyampholyte fusion protein that exhibits robust higher-order oligomerization dynamics. To conclude, this research underscores the potential significance of several high-confidence gene fusions in the progression of BMF in DC, particularly through the dysregulation of genomic stability, hematopoiesis, and tumor suppression. Additionally, we propose that these fusion proteins might hold a detrimental role, specifically in inducing proteotoxicity-driven hematopoietic disruptions. [ABSTRACT FROM AUTHOR]

Dyskeratosis congenita (DC) is a rare inherited bone marrow failure syndrome and telomere biology disorder, usullay consisting of a triad of oral leucoplakia, dystrophic nails, reticular skin pigmentation. The diagnosis in the majority of cases can be made following all the clinical findings of this triad are established. Here we report 7 years-old boy who had oral leukoplakia and nail abnormality without skin involvement, associated with bone marrow failure diagnosed with X-linked DC due to dyskerin (DKC1) mutation. Our report emphasizes the fact that clinical suspicion can prevent fatal consequences since all manifestations may not always be seen collectively. [ABSTRACT FROM AUTHOR]

Summary: Individuals with telomere biology disorders (TBDs) have very short telomeres, high risk of bone marrow failure (BMF), and reduced survival. Using data from TBD patients, a mean leukocyte Southern blot telomere length (TL) of 5 kilobases (kb) was estimated as the 'telomere brink' at which human survival is markedly reduced. However, the shortest telomere, not the mean TL, signals replicative senescence. We used the Telomere Shortest Length Assay (TeSLA) to tally TL of all 46 chromosomes in blood‐derived DNA and examined its relationship with TBDs. Patients (n = 18) had much shorter mean TL (TeSmTL) (2.54 ± 0.41 kb vs. 4.48 ± 0.52 kb, p < 0.0001) and more telomeres <3 kb than controls (n = 22) (70.43 ± 8.76% vs. 33.05 ± 6.93%, p < 0.0001). The proportion of ultrashort telomeres (<1.6 kb) was also higher in patients than controls (39.29 ± 10.69% vs. 10.40 ± 4.09%, p < 0.0001). TeS <1.6 kb was associated with severe (n = 11) compared with non‐severe (n = 7) BMF (p = 0.027). Patients with multi‐organ manifestations (n = 10) had more telomeres <1.6 kb than those with one affected organ system (n = 8) (p = 0.029). Findings suggest that TBD clinical manifestations are associated with a disproportionately higher number of haematopoietic cell telomeres reaching a telomere brink, whose length at the single telomere level is yet to be determined. [ABSTRACT FROM AUTHOR]

Purpose of Review: Telomere biology disorders (TBDs) encompass a spectrum of genetic diseases with a common pathogenesis of defects in telomerase function and telomere maintenance causing extremely short telomere lengths. Here, we review the current literature surrounding genetic testing strategies, cascade testing, reproductive implications, and the role of genetic counseling. Recent Findings: The understanding of the genetic causes and clinical symptoms of TBDs continues to expand while genetic testing and telomere length testing are nuanced tools utilized in the diagnosis of this condition. Access to genetic counseling is becoming more abundant and is valuable in supporting patients and their families in making informed decisions. Patient resources and support groups are valuable to this community. Summary: Defining which populations should be offered genetic counseling and testing is imperative to provide proper diagnoses and medical management for not only the primary patient, but also their biological relatives. [ABSTRACT FROM AUTHOR]

Dyskeratosis congenita (DC) is the first genetic syndrome identified among telomeropathies. Its classical phenotype is characterized by mucocutaneous abnormalities, atrophy and pigmentation of the skin, oral leukoplakia, and nail dystrophy. Bone marrow failure and susceptibility to malignancy are rare, and DC is mostly an X-linked recessive, serious, multisystemic disease. This study aims to increase dentists' awareness of this genetic disease, accompanied by oral findings. Two cases of DC are reported in this paper, along with a short review of the literature. Oral findings of the disease include dental caries, gingival recession, short roots, gingival bleeding, severe mobility of the teeth, and alveolar bone loss. DC is clinically seen mostly in males aged 5 to 12. This case report examines dermatological and oral findings consistent with the disease of two brothers diagnosed with DC who applied to the Gülhane Health Sciences University, Faculty of Dentistry, Pediatric Dentistry Department for dental caries complaints. DC is a rare disease, and dentists should pay attention to its systemic and oral symptoms during their examinations. Despite a positive prognosis of this disease, it is important to take into account any unexpected changes in hematological values and mucocutaneous malignant alterations. INSET: 33. [ABSTRACT FROM AUTHOR]

We are presenting a case of a boy with Revesz syndrome, and through an example of his diagnostic pathway, we are presenting a differential diagnosis of pancytopenia and aplastic anaemia. Revesz syndrome is a rare and severe form of dyskeratosis congenita, belonging to the short telomere syndromes group. In addition to changes of skin and mucous membranes and aplastic anaemia, which are typical for dyskeratosis congenita, Revesz syndrome is carcinoma predisposing syndrome, characterised by microcephaly, calcifications in the brain, intrauterine growth restriction, and exudative retinopathy. We also presented a differential diagnosis of pancytopenia and aplastic anaemia through the boy‘s diagnostic pathway.

Background. Aplastic anemia proceeds with bone marrow failure and is associated with immunological suppression of normal blood stem cells’ proliferation, which lead to bone marrow aplasia. autoimmune aggression and internal defects of blood stem cell that cause abnormal hematopoiesis are being actively studied. An important role in the pathogenesis of the aplastic anemia is played by instability of telomere length (TL). determination of the initial TL makes it possible to clearly differentiate between the aplastic anemia and dyskeratosis congenita. also, it helps to identify the group of patients with short telomeres for prediction of therapy response. Aim. To investigation the TL of various blood and bone marrow cells in patients with aplastic anemia before treatment. Materials and methods. The group of patients with aplastic anemia was investigated (n = 45). blood donors (n = 32) and bone marrow donors (n = 10) of different ages were included in the reference group. adult patients with dyskeratosis congenita (n = 5) were included in the comparison group. Relative and absolute tl was identified in peripheral blood and bone marrow mononuclear cells, monocytes, lymphocytes by flow-FISH technique (combination of flow cytometry and fluorescence in situ hybridization). Results. Relative and absolute TL was comparable in different blood and bone marrow cells in patients with aplastic anemia before treatment. TL in peripheral blood and bone marrow mononuclear cells wasn’t significantly differed in groups of patients with aplastic anemia and healthy donors. Telomeres in patients with dyskeratosis congenita were identified as “ultrashort” and were significantly shorter than in patients with aplastic anemia. Conclusion. Determination of TL in patients with aplastic anemia is modern examination method, which is a necessary step of differential diagnosis between aplastic anemia and dyskeratosis congenita, which is the disease from group of constitutional bone marrow aplasia. It is preferred to identify the TL in adult patients with aplastic anemia by the flow-FISH. It is necessary to investigate the TL to predict treatment response and to identify risks of developing adverse experiences, which include relapse and clonal evolution.

Abstract Portal hypertension (PH) refers to a collection of syndromes characterized by an increase in pressure within the portal venous system and/or elevated portal venous blood flow, most commonly caused by cirrhosis. This condition is frequently associated with viral hepatitis and chronic alcohol abuse, and its complications, such as ascites, hepatic encephalopathy, and esophageal varices, have a considerable impact on mortality. Dyskeratosis congenita (DC) is a rare genetic disorder that affects multiple systems, most notably manifesting as dystrophy of the fingernails and toenails, skin pigmentation, and mucosal leukoplakia. While cirrhotic PH is an uncommon complication of DC, we present a case of a young patient who presented with PH and had no history of hepatitis or heavy alcohol use. The patient underwent splenectomy and devascularization to treat hypersplenism and esophagogastric varices caused by PH but developed portal vein thrombosis following the surgery. Given the patient's cutaneous manifestations and cirrhosis that could not be attributed to common causes, we continued to search for the underlying cause of PH until the diagnosis of DC was finally made. The patient was subsequently treated with carvedilol to prevent variceal rebleeding and showed no significant complications or bleeding during follow‐up.

Introduction: The inherited bone marrow failure syndromes (IBMFSs) are a group of rare disorders characterized by bone marrow failure (BMF), physical abnormalities, and an increased risk of neoplasia. The National Institute of Pediatrics (INP) is a major medical institution in Mexico, where patients with BMF receive a complete approach that includes paraclinical tests. Readily recognizable features, such as the hematological and distinctive physical phenotypes, identified by clinical dysmorphologists, remain crucial for the diagnosis and management of these patients, particularly in circumstances where next-generation sequencing (NGS) is not easily available. Here, we describe a group of Mexican patients with a high clinical suspicion of an IBMFS.Methods: We performed a systematic retrospective analysis of the medical records of patients who had a high IBMFS suspicion at our institution from January 2018 to July 2021. An initial assessment included first ruling out acquired causes of BMF by the Hematology Department and referral of the patient to the Department of Human Genetics for physical examination to search for specific phenotypes suggesting an IBMFS. Patients with high suspicion of having an IBMFS were classified into two main groups: 1) specific IBMFS, including dyskeratosis congenita (DC), Diamond–Blackfan anemia (DBA), Shwachman–Diamond syndrome (SDS), thrombocytopenia with absent radii (TAR), and severe congenital neutropenia (SCN); 2) undefined IBMFS (UI).Results: We established a high suspicion of having an IBMFS in 48 patients. At initial evaluation, the most common hematologic features were bicytopenia (20%) and aplastic anemia (16%); three patients received hematopoietic stem cell transplantation. Among patients with a suspicion of an IBMFS, the most common physical abnormality was minor craniofacial features in 83% of patients and neurodevelopmental disorders in 52%. The specific suspicions that we built were DBA (31%), SDS (18%), DC (14%), TAR (4%), and SCN (4%), whereas 27% of cases remained as undefined IBMFS. SDS, TAR, and SCN were more commonly suspected at an earlier age (

Aging is the consequence of intra- and extracellular events that promote cellular senescence. Dyskeratosis congenita (DC) is an example of a premature aging disorder caused by underlying telomere/telomerase-related mutations. Cells from these patients offer an opportunity to study telomere-related aging and senescence. Our previous work has found that telomere shortening stimulates DNA damage responses (DDRs) and increases reactive oxygen species (ROS), thereby promoting entry into senescence. This work also found that telomere elongation via TERT expression, the catalytic component of the telomere-elongating enzyme telomerase, or p53 shRNA could decrease ROS by disrupting this telomere--DDR--ROS pathway. To further characterize this pathway, we performed a CRISPR/Cas9 knockout screen to identify genes that extend life span in DC cells. Of the cellular clones isolated due to increased life span, 34% had a guide RNA (gRNA) targeting CEBPB, while gRNAs targeting WSB1, MED28, and p73 were observed multiple times. CEBPB is a transcription factor associated with activation of proinflammatory response genes suggesting that inflammation may be present in DC cells. The inflammatory response was investigated using RNA sequencing to compare DC and control cells. Expression of inflammatory genes was found to be significantly elevated (P < 0.0001) in addition to a key subset of these inflammation-related genes [IL1B, IL6, IL8, IL12A, CXCL1 (GROa), CXCL2 (GROb), and CXCL5]. which are regulated by CEBPB. Exogenous TERT expression led to downregulation of RNA/protein CEBPB expression and the inflammatory response genes suggesting a telomere length-dependent mechanism to regulate CEBPB. Furthermore, unlike exogenous TERT and p53 shRNA, CEBPB shRNA did not significantly decrease ROS suggesting that CEBPB's contribution in DC cells' senescence is ROS independent. Our findings demonstrate a key role for CEBPB in engaging senescence by mobilizing an inflammatory response within DC cells. [ABSTRACT FROM AUTHOR]

Mice with a constitutive increase in p53 activity exhibited features of dyskeratosis congenita (DC), a bone marrow failure syndrome (BMFS) caused by defective telomere maintenance. Further studies confirmed, in humans and mice, that germline mutations affecting TP53 or its regulator MDM4 may cause short telomeres and alter hematopoiesis, but also revealed features of Diamond–Blackfan anemia (DBA) or Fanconi anemia (FA), two BMFSs, respectively, caused by defects in ribosomal function or DNA repair. p53 downregulates several genes mutated in DC, either by binding to promoter sequences (DKC1) or indirectly via the DREAM repressor complex (RTEL1, DCLRE1B), and the p53-DREAM pathway represses 22 additional telomere-related genes. Interestingly, mutations in any DC-causal gene will cause telomere dysfunction and subsequent p53 activation to further promote the repression of p53-DREAM targets. Similarly, ribosomal dysfunction and DNA lesions cause p53 activation, and p53-DREAM targets include the DBA-causal gene TSR2, at least 9 FA-causal genes, and 38 other genes affecting ribosomes or the FA pathway. Furthermore, patients with BMFSs may exhibit brain abnormalities, and p53-DREAM represses 16 genes mutated in microcephaly or cerebellar hypoplasia. In sum, positive feedback loops and the repertoire of p53-DREAM targets likely contribute to partial phenotypic overlaps between BMFSs of distinct molecular origins. [ABSTRACT FROM AUTHOR]

Background: Telomere biology diseases (TBD) result from defective telomere maintenance, leading to bone marrow failure. The only curative treatment for aplastic anemia related to TBD is a hematopoietic cell transplant (HCT). Although reduced‐intensity conditioning (RIC) regimens decrease transplant‐related mortality, non‐hematological phenotypes represent a major challenge and are associated with poor long‐term follow‐up outcomes. Objective: To describe the outcome of TBD patients transplanted for marrow failure. Study Design: This is a retrospective, single‐center study describing the outcomes of 32 consecutive transplants on 29 patients between 1993 and 2019. Results: The median age at transplantation was 14 years (range, 3–30 years). Most patients received a RIC regimen (n = 28) and bone marrow (BM) from an unrelated donor (n = 16). Four patients received a haploidentical transplant. Chimerism was available for 27 patients with a median time to neutrophil recovery of 20 days (13–36 days). Primary graft failure occurred in one patient, whereas second graft failure occurred in two. Acute GVHD grade II‐IV and moderate to severe chronic GVHD occurred in 22% of patients at risk. Fourteen patients were alive after HCT at the last follow‐up (median, 6 years; 1.4–19 years). The 5‐year overall survival was better after matched sibling donor (MSD) transplantation compared to other hematopoietic stem cell sources (88.9% vs. 47.7%; p =.05; CI = 95%). Overall, 15 patients died after HCT, most of them (n = 11) after the first year of transplant, due to non‐hematological disease progression or complication of chronic GVHD. Conclusions: Hematopoietic cell transplantation is a potentially curative treatment option for TBD, nonetheless the poor outcome reflects the progression of non‐hematologic disease manifestations, which should be considered when transplantation is indicated. [ABSTRACT FROM AUTHOR]

Background. Telomeres inhibit DNA damage response at the ends of the chromosome to suppress cell cycle arrest as well as ensure genome stability. Dyskeratosis congenita (DC), a telomere-related disease, includes the classical triad involving oral leukoplakia, dysplastic nails, and lacy reticular pigment in the neck and/or upper chest. Hoyeraal-Hreidarrson syndrome (HHS), a severe manifestation of DC, frequently occurs during childhood, and patients with HHS often show short-term survival and thus do not exhibit all mucocutaneous manifestations or syndromic features. Case. We report here a patient with HHS characterized by the proband's clinical attributes, such as growth delay, bone marrow failure, microcephaly, defects in body development, and the absence of cerebellar hypoplasia combined with Blake's pouch cyst. By using exome sequencing, novel compound heterozygous mutations (c.1451C>T and c.1266+3del78bp) were detected in the RTEL1 (regulator of telomere elongation helicase 1) gene. Conclusions. The DNA helicase RTEL1 plays a role in genome stability, DNA replication, telomere maintenance, and genome repair. Terminal restriction fragment length analysis revealed a significantly shorter telomere length of the proband. Our findings provided evidence that compound heterozygous RTEL1 mutations cause HHS. [ABSTRACT FROM AUTHOR]

Dyskeratosis congenita (DC) is a rare multisystem clinical entity caused by genetic mutations associated with telomere biology disorder. The symptoms include bone marrow dysfunction as well as skin and mucosal abnormalities. In severe cases, DC is characterized by high mortality rates among children. In milder subtypes, it is less detectable in adults, due to the occurrence of cryptic forms of the disease. To date, more than 15 mutated genes have been shown as causative for DC. The aim of this study was to provide a brief description of the currently known clinical and genetic characteristics of DC, and to elucidate the molecular pathogenesis. [ABSTRACT FROM AUTHOR]

Inherited bone marrow failure syndromes are disorders of hematopoiesis that are mostly encountered in childhood. Taking the basis from genetics, they are characterized by pancytopenia, increased risk of developing myelodysplastic syndrome and malignancy. Extrahematopoietic presentations are observed often in addition to symptoms related to defective hematopoiesis (also known as bone marrow failure). The biology, clinical features, and management of the main syndromes such as Fanconi anemia, dyskeratosis congenita, Shwachman-Diamond syndrome, congenital amegakaryocytic thrombocytopenia, Diamond-Blackfan anemia, and severe congenital neutropenia are briefly summarized in this review.

Inherited bone marrow failure syndromes (IBMFSs) include Fanconi anemia, Diamond–Blackfan anemia, Shwachman–Diamond syndrome, dyskeratosis congenita, severe congenital neutropenia, and other rare entities such as GATA2 deficiency and SAMD9/9L mutations. The IBMFS monogenic disorders were first recognized by their phenotype. Exome sequencing has validated their classification, with clusters of gene mutations affecting DNA damage response (Fanconi anemia), ribosome structure (Diamond–Blackfan anemia), ribosome assembly (Shwachman–Diamond syndrome), or telomere maintenance/stability (dyskeratosis congenita). The pathogenetic mechanisms of IBMFSs remain to be characterized fully, but an overarching hypothesis states that different stresses elicit TP53-dependent growth arrest and apoptosis of hematopoietic stem, progenitor, and precursor cells. Here, we review the IBMFSs and propose a role for pro-inflammatory cytokines, such as TGF-β, IL-1β, and IFN-α, in mediating the cytopenias. We suggest a pathogenic role for cytokines in the transformation to myeloid neoplasia and hypothesize a role for anti-inflammatory therapies. [ABSTRACT FROM AUTHOR]

Reticulate pigmentary disorders (RPDs) are a group of inherited and acquired skin conditions characterized by hyperpigmented and/or hypopigmented macules. Inherited RPDs include dyschromatosis symmetrica hereditaria (DSH), dyschromatosis universalis hereditaria (DUH), reticulate acropigmentation of Kitamura (RAK), Dowling-Degos disease (DDD), dyskeratosis congenita (DKC), Naegeli–Franceschetti–Jadassohn syndrome (NFJS), dermatopathia pigmentosa reticularis (DPR), and X-linked reticulate pigmentary disorder. Although reticulate pattern of pigmentation is a common characteristic of this spectrum of disorders, the distribution of pigmentation varies among these disorders, and there may be clinical manifestations beyond pigmentation. DSH, DUH, and RAK are mostly reported in East Asian ethnicities. DDD is more common in Caucasians, although it is also reported in Asian countries. Other RPDs show no racial predilection. This article reviews the clinical, histological, and genetic variations of inherited RPDs. [ABSTRACT FROM AUTHOR]

Background & Aims: Dyskeratosis congenita (DC) is a telomere biology disorder caused primarily by mutations in the DKC1 gene. Patients with DC and related telomeropathies resulting from premature telomere dysfunction experience multiorgan failure. In the liver, DC patients present with nodular hyperplasia, steatosis, inflammation, and cirrhosis. However, the mechanism responsible for telomere dysfunction–induced liver disease remains unclear. Methods: We used isogenic human induced pluripotent stem cells (iPSCs) harboring a causal DC mutation in DKC1 or a CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/Cas9)–corrected control allele to model DC liver pathologies. We differentiated these iPSCs into hepatocytes (HEPs) or hepatic stellate cells (HSCs) followed by generation of genotype-admixed hepatostellate organoids. Single-cell transcriptomics were applied to hepatostellate organoids to understand cell type–specific genotype-phenotype relationships. Results: Directed differentiation of iPSCs into HEPs and stellate cells and subsequent hepatostellate organoid formation revealed a dominant phenotype in the parenchyma, with DC HEPs becoming hyperplastic and also eliciting a pathogenic hyperplastic, proinflammatory response in stellate cells independent of stellate cell genotype. Pathogenic phenotypes in DKC1-mutant HEPs and hepatostellate organoids could be rescued via suppression of serine/threonine kinase AKT (protein kinase B) activity, a central regulator of MYC-driven hyperplasia downstream of DKC1 mutation. Conclusions: Isogenic iPSC-derived admixed hepatostellate organoids offer insight into the liver pathologies in telomeropathies and provide a framework for evaluating emerging therapies.

Objectives Dyskeratosis congenita (DC) is a rare inherited disease characterized by the triad of reticulate hyperpigmentation, nail dystrophy and oral leukoplakia. DC patients are considered vulnerable to external pressure, such as immunochemotherapy. There are very few cases reporting severe therapy-induced toxicities in patients with DC.Methods A 27-year-old woman was admitted to our hospital with a 4-month history of pancytopenia and a 7-day history of dyspnea with coughing. She was diagnosed with non-Hodgkin’s lymphoma 5 months ago. She received immunochemotherapy due to non-Hodgkin’s lymphoma but experienced recurrent fever, oral ulcer, pancytopenia, dyspnea and other symptoms during immunochemotherapy. On admission, she experienced an aggravation of respiratory symptoms, recurrent infections and acute heart failure.Results Laboratory examination confirmed pancytopenia, and chest computed tomography showed interstitial lung disease (ILD). Genetic analysis results confirmed the presence of DC and a TINF2 gene mutation. With continuous supportive and anti-infection treatment, her condition finally stabilized. She was discharged from the hospital after nearly 2 months.Discussion We reviewed similar cases and found common features that could be useful. However, the reported cases are very limited. More cases and studies are needed.Conclusion These cases indicate that DC patients seem more vulnerable to therapy toxicities; thus, physicians should be careful when treating these patients with chemotherapy drugs or radiation therapy. Reduced-intensity therapy may be considered.

Classic dyskeratosis congenita is a hereditary disease where the majority of patients present with bone marrow failure and mucocutaneous changes: mainly skin pigmentation, nail dystrophy, oral premalignant leukoplakia, in addition to increased risk for malignancies. A 63-year-old man with a long history of untreated chronic pulmonary disease, a smoker in the past, presented initially with pancytopenia and a clinical diagnosis of myelodysplastic syndrome with excess blasts returned a month later with leukocytosis (WBC 215.9 × 106/μL) and diagnosed with acute myeloid leukemia (AML) with deletion of chromosome 7 and FLT3-TKD mutation. The patient’s mother and sister died in their 6th decade from rapidly progressing fulminant pulmonary fibrosis. He had abnormal skin pigmentation and oral leukoplakia on presentation. He was induced with 7 + 3 chemotherapy and started on midostaurin but experienced prolonged cytopenias, complicated by hypoxic acute on chronic respiratory failure requiring intubation and mechanical ventilation. D + 28 and D + 36 bone marrow examination showed trilineage hypoplasia but no blasts, though the D + 28 bone marrow biopsy revealed one metaphase with del (7) that was cleared on D + 35. The constellation of clinical features and strong family history along with del 7 and FLT3-TKD AML with preceding MDS highly suggests a germline predisposition state dyskeratosis congenita. Germline predispositions are often underrecognized as delayed onset conditions leading to AML and may have treatment and preventative implications especially genetic counseling for blood-related family members.