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Archives of Dermatological Research Jun 2024Dyskeratosis congenita (DC) is a telomeropathy presenting diagnostic and therapeutic challenges across multiple specialties; yet, subtle dermatological signs enable... (Review)
Review
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.
Topics: Humans; Dyskeratosis Congenita; Mutation, Missense; Telomerase; Male; Female; Dermatologists; Skin
PubMed: 38940945
DOI: 10.1007/s00403-024-03050-9 -
Skin Appendage Disorders Apr 2024Bowen's disease is a squamous cell carcinoma in situ, the most common malignancy of the nail unit. Presenting more frequently in the fingernails, common risk factors...
INTRODUCTION
Bowen's disease is a squamous cell carcinoma in situ, the most common malignancy of the nail unit. Presenting more frequently in the fingernails, common risk factors include ionizing radiation, oral exposure to arsenic or pesticides, dyskeratosis congenita, and quite commonly diverse subtypes of HPV. We report the first case of multiple periungual pigmented Bowen's disease in a pediatric patient.
CASE PRESENTATION
A healthy 13-year-old boy presented with a 9-month history of a pigmented erythematous patch on the proximal nail fold of his 3rd right finger without associated symptoms. A punch biopsy was taken, and the diagnosis of Bowen's disease was made. The patient received photodynamic therapy and three cycles of imiquimod without response, and two new lesions appeared on the first and second right fingers. Surgical removal was performed on all lesions. A polymerase chain reaction detected an HPV type 16.
DISCUSSION/CONCLUSION
Multiple periungual Bowen's disease is rare, with the most frequent risk factors being HPV infection and chronic immunosuppression. Less than 10% of the cases present as longitudinal melanonychia. To date, there are no previous reports of multiple pigmented periungual Bowen's disease. HPV-induced Bowen's disease is usually present in adults aged between 22 and 89 years as persistent verrucae. In this case, koilocytosis and the fact that all lesions appeared on the right hand are suggestive of HPV infection.
PubMed: 38572196
DOI: 10.1159/000534734 -
G3 (Bethesda, Md.) Jun 2024In humans, the prevalence of congenital microphthalmia is estimated to be 0.2-3.0 for every 10,000 individuals, with nonocular involvement reported in ∼80% of cases....
In humans, the prevalence of congenital microphthalmia is estimated to be 0.2-3.0 for every 10,000 individuals, with nonocular involvement reported in ∼80% of cases. Inherited eye diseases have been widely and descriptively characterized in dogs, and canine models of ocular diseases have played an essential role in unraveling the pathophysiology and development of new therapies. A naturally occurring canine model of a syndromic disorder characterized by microphthalmia was discovered in the Portuguese water dog. As nonocular findings included tooth enamel malformations, stunted growth, anemia, and thrombocytopenia, we hence termed this disorder Canine Congenital Microphthalmos with Hematopoietic Defects. Genome-wide association study and homozygosity mapping detected a 2 Mb candidate region on canine chromosome 4. Whole-genome sequencing and mapping against the Canfam4 reference revealed a Short interspersed element insertion in exon 2 of the DNAJC1 gene (g.74,274,883ins[T70]TGCTGCTTGGATT). Subsequent real-time PCR-based mass genotyping of a larger Portuguese water dog population found that the homozygous mutant genotype was perfectly associated with the Canine Congenital Microphthalmos with Hematopoietic Defects phenotype. Biallelic variants in DNAJC21 are mostly found to be associated with bone marrow failure syndrome type 3, with a phenotype that has a certain degree of overlap with Fanconi anemia, dyskeratosis congenita, Shwachman-Diamond syndrome, Diamond-Blackfan anemia, and reports of individuals showing thrombocytopenia, microdontia, and microphthalmia. We, therefore, propose Canine Congenital Microphthalmos with Hematopoietic Defects as a naturally occurring model for DNAJC21-associated syndromes.
Topics: Animals; Dogs; Microphthalmos; Disease Models, Animal; Genome-Wide Association Study; Phenotype; Genotype; Homozygote; Dog Diseases; Syndrome; Female; Male
PubMed: 38682429
DOI: 10.1093/g3journal/jkae067 -
Indian Journal of Dermatology 2024Dyskeratosis congenita (DC) is a rare inherited bone marrow failure syndrome and telomere biology disorder, usullay consisting of a triad of oral leucoplakia, dystrophic...
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.
PubMed: 38572035
DOI: 10.4103/ijd.ijd_556_23 -
Frontiers in Genetics 2023The inherited bone marrow failure syndromes (IBMFSs) are a group of rare disorders characterized by bone marrow failure (BMF), physical abnormalities, and an increased...
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. 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) , including dyskeratosis congenita (DC), Diamond-Blackfan anemia (DBA), Shwachman-Diamond syndrome (SDS), thrombocytopenia with absent radii (TAR), and severe congenital neutropenia (SCN); 2) 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). 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.
PubMed: 38327701
DOI: 10.3389/fgene.2023.1293929 -
Experimental Hematology Jun 2024Inherited bone marrow failure syndromes often result from pathogenic mutations in genes that are important for ribosome function, namely, Diamond-Blackfan anemia,...
Inherited bone marrow failure syndromes often result from pathogenic mutations in genes that are important for ribosome function, namely, Diamond-Blackfan anemia, Shwachman-Diamond syndrome, and dyskeratosis congenita. Germline mutations in SAMD9 are a frequent genetic lesion resulting in an inherited bone marrow failure syndrome with monosomy 7; some patients have severe multisystem syndromes that include myelodysplasia. The association of germline SAMD9 mutations and bone marrow failure is clear; however, to date, there is no reliable method to predict whether a novel SAMD9 mutation is pathogenic unless it is accompanied by an obvious family history and/or clinical syndrome. The difficulty with pathogenicity prediction is, in part, due to the incomplete understanding of the biological functions of SAMD9. We used a SAMD9-targeted, inducible CRISPRa system and RNA sequencing to better understand the global transcriptional changes that result from transcriptional manipulation of SAMD9. Supporting recent discoveries that SAMD9 acts as a ACNase specific for phenylalanine tRNA (tRNA-Phe), we confirmed with crosslinking and solid-phase purification that SAMD9 is an RNA binding protein and analyzed how overexpression of tRNA-Phe may reverse transcriptomic changes caused by SAMD9 activation. Our data show that overexpression of SAMD9 from the endogenous locus results in decreased cell proliferation, cell cycle progression, and global protein translation. When SAMD9 contains a gain-of-function mutation (p.E1136Q), these functional phenotypes are exacerbated but only partially rescued with tRNA-Phe overexpression, suggesting additional molecular actions of SAMD9. Additionally, we demonstrate that gene expression pathways important for ribosome biogenesis and MYC signaling are the most significantly impacted by SAMD9 overexpression.
PubMed: 38848876
DOI: 10.1016/j.exphem.2024.104249 -
Annals of Hematology Dec 2023
Topics: Humans; Dyskeratosis Congenita; RNA; Mutation; Telomerase; Telomere
PubMed: 37684378
DOI: 10.1007/s00277-023-05424-x -
Human Molecular Genetics Apr 2024Telomeres are nucleoprotein structures at the end of chromosomes that maintain their integrity. Mutations in genes coding for proteins involved in telomere protection...
Clinical mutations in the TERT and TERC genes coding for telomerase components induced oxidative stress, DNA damage at telomeres and cell apoptosis besides decreased telomerase activity.
Telomeres are nucleoprotein structures at the end of chromosomes that maintain their integrity. Mutations in genes coding for proteins involved in telomere protection and elongation produce diseases such as dyskeratosis congenita or idiopathic pulmonary fibrosis known as telomeropathies. These diseases are characterized by premature telomere shortening, increased DNA damage and oxidative stress. Genetic diagnosis of telomeropathy patients has identified mutations in the genes TERT and TERC coding for telomerase components but the functional consequences of many of these mutations still have to be experimentally demonstrated. The activity of twelve TERT and five TERC mutants, five of them identified in Spanish patients, has been analyzed. TERT and TERC mutants were expressed in VA-13 human cells that express low telomerase levels and the activity induced was analyzed. The production of reactive oxygen species, DNA oxidation and TRF2 association at telomeres, DNA damage response and cell apoptosis were determined. Most mutations presented decreased telomerase activity, as compared to wild-type TERT and TERC. In addition, the expression of several TERT and TERC mutants induced oxidative stress, DNA oxidation, DNA damage, decreased recruitment of the shelterin component TRF2 to telomeres and increased apoptosis. These observations might indicate that the increase in DNA damage and oxidative stress observed in cells from telomeropathy patients is dependent on their TERT or TERC mutations. Therefore, analysis of the effect of TERT and TERC mutations of unknown function on DNA damage and oxidative stress could be of great utility to determine the possible pathogenicity of these variants.
Topics: Humans; Apoptosis; DNA; DNA Damage; Dyskeratosis Congenita; Mutation; Oxidative Stress; RNA; Telomerase; Telomere
PubMed: 38641551
DOI: 10.1093/hmg/ddae015 -
Journal of Pediatric Hematology/oncology Jan 2024Dyskeratosis congenita is a rare inherited disease with classic cutaneous symptoms, sometimes accompanied with more severe extracutaneous manifestations such as bone...
Dyskeratosis congenita is a rare inherited disease with classic cutaneous symptoms, sometimes accompanied with more severe extracutaneous manifestations such as bone marrow failure, which can be lethal. Eltrombopag is an orally available thrombopoietin receptor agonist in clinical use for increasing platelet levels in patients with immune thrombocytopenia and aplastic anemia. Here, 3 pediatric patients with dyskeratosis congenita are presented with varying disease severity, in which off-label eltrombopag treatment had no clinical effect on bone marrow failure. This, in addition to the negative results in a previous case report, supports the preclusion of eltrombopag use in dyskeratosis congenita.
Topics: Humans; Child; Dyskeratosis Congenita; Bone Marrow Failure Disorders; Anemia, Aplastic; Pancytopenia; Thrombocytopenia
PubMed: 37885072
DOI: 10.1097/MPH.0000000000002775 -
ERJ Open Research Jan 2024Pulmonary fibrosis is a severe disease which can be familial. A genetic cause can only be found in ∼40% of families. Searching for shared novel genetic variants may...
INTRODUCTION
Pulmonary fibrosis is a severe disease which can be familial. A genetic cause can only be found in ∼40% of families. Searching for shared novel genetic variants may aid the discovery of new genetic causes of disease.
METHODS
Whole-exome sequencing was performed in 152 unrelated patients with a suspected genetic cause of pulmonary fibrosis from the St Antonius interstitial lung disease biobank. Variants of interest were selected by filtering for novel, potentially deleterious variants that were present in at least three unrelated pulmonary fibrosis patients.
RESULTS
The novel c.586G>A p.(E196K) variant in the gene was observed in three unrelated patients: two familial patients and one sporadic patient, who was later genealogically linked to one of the families. The variant was identified in nine additional relatives with pulmonary fibrosis and other telomere-related phenotypes, such as pulmonary arterial venous malformations, emphysema, myelodysplastic syndrome, acute myeloid leukaemia and dyskeratosis congenita. One family showed incomplete segregation, with absence of the variant in one pulmonary fibrosis patient who carried a variant. The majority of variant carriers showed short telomeres in blood. ZCCHC8 protein was located in different lung cell types, including alveolar type 2 (AT2) pneumocytes, the culprit cells in pulmonary fibrosis. AT2 cells showed telomere shortening and increased DNA damage, which was comparable to patients with sporadic pulmonary fibrosis and those with pulmonary fibrosis carrying a telomere-related gene variant, respectively.
DISCUSSION
The c.586G>A variant confirms the involvement of ZCCHC8 in pulmonary fibrosis and short-telomere syndromes and underlines the importance of including the gene in diagnostic gene panels for these diseases.
PubMed: 38375433
DOI: 10.1183/23120541.00487-2023