scholarly journals Androgen Derivatives Improve Blood Counts and Elongate Telomere Length in Patients with Dyskeratosis Congenita

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 2585-2585 ◽  
Author(s):  
Martin Kirschner ◽  
Monica Sofia Ventura Ferreira ◽  
Anne-Sophie Bouillon ◽  
Marcin W. Wlodarski ◽  
Michaela Schwarz ◽  
...  
Keyword(s):  
Telomere Length ◽  
Peripheral Blood ◽  
Research Funding ◽  
Somatic Mutations ◽  
Bone Marrow Failure ◽  
Dyskeratosis Congenita ◽  
Telomere Maintenance ◽  
Treatment Start ◽  
Increased Risk

Abstract Introduction: Classical Dyskeratosis Congenita (DKC) is a systemic disorder characterized mainly by mucocutaneous features and bone marrow failure. DKC is caused by mutations affecting proper telomere maintenance leading to premature telomere shortening. Clinically, assessment of telomere length (TL) is being used for screening and diagnosis of DKC. Previous studies showed that androgen derivatives (AD) such as danazol or oxymetholone can improve blood counts and reduce transfusion frequency in patients with DKC. Reports from in vitro studies suggest that AD can increase the expression of telomerase and elongate telomeres reversing at least partially the mutation-related haploinsufficiency of the telomerase complex. However, whether telomere elongation can be observed in vivo is still controversial. Patients with DKC have an increased risk of developing solid tumors and acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS). Malignant transformation occurs mostly by chromosomal instability mediated by critical short telomeres and not via clonal hematopoiesis (CHIP) and eventual selection for MDS-related somatic mutations. The question whether increased telomerase activity by AD increases the risk for additional MDS-related mutations is unclear. In our study, we aimed to investigate TL and MDS-related somatic mutations in DKC patients undergoing treatment with AD. Methods and Patients: 5 patients enrolled in the Aachen Telomeropathy Registry (ATR) that underwent AD treatment were included in the analysis. All patients had molecularly confirmed DKC (4 patients having mutations in TERC, 1 patient in TERT). TERC mutated patients received danazol treatment (mean dosage 625 mg per day) while the patient with TERT mutation was treated with low dose oxymetholone (0.22mg/kg) per day. Patients were at a median age of 43.1 (range from 21.7 to 53.8) years. Median duration of treatment with AD was 14 months (3 to 29 mo) and is actually ongoing in all patients treated with danazol. Follow-up for blood counts and TL length assessment was carried out after median 14 months after treatment start with AD. TL assessment and blood counts of the patient receiving oxymetholone was carried out at the end of AD treatment after 29 months. All patients underwent next-generation sequencing (NGS) analysis using custom NGS-panel including frequent genes implicated in MDS development. Quality parameters of the NGS analysis were satisfactory (Q30>85%) and 95% of the expected area was covered at minimum 300x. To minimize risk of detecting sequencing errors, a threshold of 10 (absolute) and 5% (relative) variant allele frequency (VAF) was chosen. TL assessment of peripheral blood granulocytes and lymphocytes was carried out by Flow-FISH and all results are given in kb. Results: Analysis of the peripheral blood counts revealed a significant increase in platelets counts from mean 56/nl ±50 S.D. before treatment to 88/nl ±49 (p=0.03) during treatment. Similar results were observed for leukocyte counts increasing significantly from 3.83/µl±1.86 to 4.70/µl±2.88 (p=0.04). Hemoglobin counts showed a non-significant increase from 8.9 g/dl ±2.6 to 10.2 g/dl ±2.9 (p=0.13, all student paired t-test). Focusing on TL, lymphocyte TL increased significantly from 4.32kb±0.47 to 5.13kb ±0.57 (p=0.001). TL in the granulocyte subpopulation increased from 4.73kb±0.33 before treatment start to 6.10kb±0.50 under treatment (p=0.026). Calculated median increase in TL per months for lymphocytes and granulocytes was 0.092 kb (0.019 to 0.223 kb) and 0.166 kb (0.019kb to 0.513kb). Finally, NGS analysis for possible MDS-related mutations did not reveal any mutations before and under AD treatment. Conclusions: Based on our data in this genetically homogenous cohort of 5 patients with mutations in the telomerease genes TERC and TERT and short TL, AD significantly improve blood counts and elongate telomeres in granulocytes and lymphocytes. No MDS-related somatic mutations were observed during telomerase activation with AD. Pending longer follow up, treatment with AD seems to represent an efficient and safe therapy for patients with TERT or TERC mutations. Whether AD persistently elongate telomeres in DKC patients and how much this is dependent on the underlying DKC-related mutation requires further investigation. Disclosures Kirschner: Basilea Pharmaceutica: Other: travel support; BMS: Consultancy; Bayer: Consultancy; Roche: Consultancy. Wilop:Medizinwelten-Services GmbH: Honoraria; Amgen: Consultancy; Celgene: Consultancy, Honoraria, Other: Travel grant; Bristol-Myers Squibb: Honoraria. Brümmendorf:Pfizer: Consultancy, Research Funding; Janssen: Consultancy; Novartis: Consultancy, Research Funding; Takeda: Consultancy; Merck: Consultancy. Beier:Gilead: Other: travel support; Celgene: Other: travel support.

A Novel hTERC Deletion Manifesting with Features of Dyskeratosis Congenita and Genetic Anticipation.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4157-4157
Author(s):  
Stan Benke ◽  
D. S. Houston ◽  
Inderjeet Dokal ◽  
Tom Vulliamy
Keyword(s):  
Bone Marrow ◽  
Telomere Length ◽  
Peripheral Blood ◽  
Autosomal Dominant ◽  
Bone Marrow Failure ◽  
Macrocytic Anemia ◽  
Phenotypic Expression ◽  
Dyskeratosis Congenita ◽  
Sequencing Analysis ◽  
Genetic Anticipation

Abstract The gene encoding the RNA component of human telomerase (hTERC) is mutated in families with the autosomal dominant form of dyskeratosis congenita (DC). The phenomenon of genetic anticipation has recently been reported to accompany this form of DC, with disease severity increasing in offspring of affected individuals. It has been postulated that anticipation in these families relates to the adverse impact of hTERC mutations on inherited telomere length, with progressive telomere shortening seen in succeeding generations (Nat Gen2004; 36:447). We describe here a novel hTERC mutation, with affected individuals presenting in adulthood with mild mucocutaneous abnormalities, bone marrow failure and a pattern of penetrance supporting the presence of disease anticipation. The proband in the family studied presented at age 49 with squamous cell carcinoma of the tongue and a history of oral leukoplakia which he had developed at age 30. Peripheral blood on presentation was remarkable only for a mild macrocytic anemia. During treatment of his malignancy, severe and irreversible bone marrow hypoplasia was precipitated by a single cycle of cisplatinum chemotherapy. The patient’s brother at age 25 had been previously diagnosed with severe aplastic anemia; this was refractory to standard immunosuppression with cyclosporine and antithymocyte globulin. No somatic abnormailites were identified in this patient. Testing for Fanconi anemia in both siblings was negative. Direct sequencing analysis of hTERC in these patients revealed both to be heterozygous for a novel hTERC mutation (79 deletion C). Further studies among family members documented heterozygosity for the mutation in the mother of these two siblings. At age 77, she displayed none of the mucocutaneous signs associated with DC, while the only abnormality seen in her peripheral blood was an elevated mean corpuscular volume. The hTERC mutation seen in this family most likely exerts its effects through disruption of the pseudoknot domain. The findings of an individual with normal longevity, minimal phenotypic expression and affected offspring are further evidence of genetic anticipation being an important feature of autosomal dominant DC. Correlation with determination of telomere length has been initiated.

Accelerated Telomere Shortening Identifies a Subgroup of Patients with Myelodysplastic Syndrome and Isolated 5q Minus Deletion with a Higher Probability of Response to Lenalidomide Treatment

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 3809-3809
Author(s):  
Fabian Beier ◽  
Ralph P Schneider ◽  
Guntram Buesche ◽  
Jens Panse ◽  
Ulrich Germing ◽  
...  
Keyword(s):  
Stem Cell ◽  
Telomere Length ◽  
Peripheral Blood ◽  
Preliminary Analysis ◽  
Research Funding ◽  
Disease Duration ◽  
Treatment Initiation ◽  
Telomere Shortening ◽  
Length Analysis

Abstract Abstract 3809 Introduction: Myelodysplastic syndromes (MDS) are heterogeneous clonal stem cell disorders characterized by ineffective hematopoiesis and an increased risk for leukemic transformation. Lenalidomide (LEN) was found to be an effective treatment particularly in a subset of MDS patients with isolated 5q minus deletion (del5q). A high proportion of these patients show erythroid response with transfusion independence and even complete cytogenetic response (CCR). However, particularly in patients not responding to LEN, disease progression to acute leukemia is observed. Accelerated telomere length shortening is regularly observed in hematopoietic stem cell disorders with increased stem cell turnover and/or altered telomere maintenance. Dysfunctional telomeres have been found to play an important role in the development of chromosomal instability and malignant transformation. The aim of this study was to investigate telomere length as a potential predictive biomarker in MDS del5q patients treated with LEN with regard to disease progression and treatment response. Methods and Patients: Telomere length (TL) was determined using confocal Q-FISH on paraffin-embedded BM biopsies of 54 MDS patients enrolled in the LEMON5 study (NCT01081431). Criteria for study inclusion were isolated del5q, transfusion dependence of at least one unit per 8 weeks and IPSS low risk and intermediate-1. TL was analyzed in a blinded fashion on specimen obtained before treatment initiation with LEN, control biopsies of 11 patients with newly diagnosed Morbus Hodgkin without BM affection were used for age-adaption of TL. At the time of this preliminary analysis, the study is ongoing, initial clinical data were available for 94% (51/54) and detailed follow up data for 63% (34/54) of the patients with a median follow up of 22 months. Mean age of the MDS patients was 68.6 years (range 40–87) and average disease duration before enrolment was 2.9 years. Results: We found that TL of the 54 MDS patients was significantly shorter compared to the age-adjusted TL (−0.57 kb, p=0.02, n=54). Interestingly, analysis according to the respective IPSS showed significant shorter telomeres in the low risk group (−0.91 kb, p=0.04, n=27) than in the intermediate-1 group (−0.55 kb, p=0.24, n=19). Focusing on the peripheral blood counts, cut-off values were set according to the distribution pattern representing the approximate median value. Patients with ANC counts <2000/μl (−0.98 kb, p=0.03, n=27), haemoglobin values <9g/dl (−0.89 kb, p=0.02, n=26) and platelets counts <300/nl (−0.87 kb, p=0.01, n=27) had significantly shortened telomeres compared to the age-adjusted controls. In contrast, patients with ANC counts >2000/μl (0.06 kb, p=0.9, n=20), haemoglobin >9g/dl (−0.23 kb, p=0.23, n=25) and platelet counts >300/nl (−0.07 kb, p=0.58, n=24) did not differ from the age-adjusted TL. Furthermore, patients with a history of more than 2 years of MDS had significantly shortened age-adjusted telomere length (−0.94 kb, p=0.02, n=26), but that was not the case in patients with a short disease duration (<2 years; −0.32 kb, p=0.36, n=28). Interestingly, with regards to response to LEN, patients later achieving a CCR under LEN had significantly shortened TL at treatment initiation (−1.47 kb, n=14, p=0.005) whereas this was not the case in patients with no response, relapse or progressive disease during follow-up (−0.23 kb, n=20, p=0.62). Furthermore, correlation with treatment duration showed that patients receiving more than 12 cycles of LEN (in which 93%, i.e. 13/14 patients were responding) had significantly shorter telomeres before start of LEN (−1.41 kb, n=17, p=0.02) compared to the group of patients with less than 12 cycles (0.22 kb, n=14) in which 41%, i.e. 7/17 patients were responding. Conclusions: Patients with MDS and isolated del5q undergo significant telomere shortening. Using telomere length analysis on paraffin-embedded BM biopsies using confocal Q-FISH, we were able to identify a subgroup of patients with lower peripheral blood counts and accelerated TL shortening that seemed to preferentially profit from LEN treatment. In summary and pending further confirmation with longer follow up of this preliminary analysis within the ongoing LeMon5 study, we conclude that telomere length analysis may identify a distinct biological subentity of MDS del5q patients more likely to benefit from treatment with LEN. Disclosures: Germing: Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Brümmendorf:Celgene: Research Funding.

Telomere Length Of Granulocytes Significantly Increases During The First Six Months Of Lenalidomide Treatment In Patients With Isolated 5q- Syndrome

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 2781-2781
Author(s):  
Fabian Beier ◽  
Ulrich Germing ◽  
Guntram Büsche ◽  
Patrick Ziegler ◽  
Stefan Wilop ◽  
...  
Keyword(s):  
Telomere Length ◽  
Research Funding ◽  
Clonal Evolution ◽  
Leukemic Transformation ◽  
Telomere Elongation ◽  
Treatment Start ◽  
Potential Biomarker ◽  
Increased Risk ◽  
Pre Treatment ◽  
Telomere Biology

Abstract Introduction Myelodysplastic syndromes (MDS) are a group of heterogeneous clonal stem cell disorders characterized by ineffective hematopoiesis and an increased risk for leukemic transformation. Lenalidomide (LEN) was found to be an effective treatment particularly in a subset of MDS patients with isolated 5q deletion (del5q). Telomere length (TL) predicts replicative potential of eukaryotic cells and dysfunctional telomeres have been found to play an important role in the development of chromosomal instability and malignant transformation. The aim of this study was to investigate telomere biology during LEN treatment as a potential biomarker for clonal evolution and leukemic transformation of patients with MDS del5q. Methods and Patients TL of granulocytes and lymphocytes in the peripheral blood of 45 MDS patients enrolled in the LEMON5 study (NCT01081431) and 108 healthy controls (used for age-adaption of TL) were measured using quantitative telomere flow-FISH. Criteria for study inclusion were isolated del5q, IPSS low risk and intermediate-1 as well as transfusion dependence of at least one unit per 8 weeks. Mean age of the MDS patients was 66 years (range 42-88) and follow-up measurement were carried out before as well as 6 and 12 months after treatment start, respectively. Results We found that mean age-adjusted TL in granulocytes was only slightly shortened compared to age-adjusted normal individuals (-0.31 kb, n=22). However, under LEN treatment, TL significantly increased during the first six months (ΔTL: +0.71 kb, n=17 p=0.01) and twelve months after treatment start (ΔTL: +0.86 kb, n=16, p=0.02; both time points compared to pre-treatment results, respectively). In contrast, TL of lymphocytes did not change significantly from pre-treatment (ΔTL: -0.11 kb, n=22) compared to months six (ΔTL: +0.15 kb, n=17) and months twelve (ΔTL: +0.04 kb, n=15). Interestingly, in five patients with sequential measurements of granulocytes available, the following pattern was detected: 3/5 patients showed telomere elongation, 1/5 had stable TL and 1/5 expressed telomere shortening (TS) during the first six months. Two patients were further followed up to 12 months after treatment initiation and showed either TS or elongation. Conclusions Mean telomere length in granulocytes of patients with MDS and isolated del5q increases significantly during the first year of LEN treatment while in the same time period, TL in lymphocytes remains unchanged. Whether telomere elongation is due to direct effects of LEN on telomerase and/or telomeres in clonal MDS del5q stem cells themselves (e.g. by telomerase upregulation) or due to a shift from dysplastic clonal towards normal hematopoiesis is currently under investigation. Upon validation, absolute TL and/or increase of telomere length under treatment (ΔTL) might become a promising novel biomarker for treatment response to LEN. Disclosures: Beier: Celgene: Travel grant Other. Germing:Celgene: Honoraria, Research Funding. Büsche:Celgene: Research Funding. Gattermann:Celgene: Honoraria, Research Funding; Novartis: Honoraria, Research Funding. Platzbecker:Novartis: Honoraria, Research Funding; Celgene: Honoraria, Research Funding. Götze:Celgene Corp.: Honoraria. Hofmann:Celgene: Honoraria, Research Funding. Brümmendorf:Celgene: Honoraria, Research Funding.

scholarly journals Clonal hematopoiesis in the inherited bone marrow failure syndromes

Blood ◽  
2020 ◽  
Author(s):  
Frederick D Tsai ◽  
R. Coleman Lindsley
Keyword(s):  
Bone Marrow ◽  
Tumor Suppressor ◽  
Malignant Transformation ◽  
Somatic Mutations ◽  
Bone Marrow Failure ◽  
Telomere Maintenance ◽  
Clonal Hematopoiesis ◽  
Bone Marrow Failure Syndromes ◽  
Increased Risk ◽  
Somatic Alterations

Inherited bone marrow failure syndromes (IBMFS) are characterized by ineffective hematopoiesis and increased risk of developing myeloid malignancy. The pathophysiologies of different IBMFS are variable, and can relate to defects in diverse biological processes, including DNA damage repair (Fanconi anemia), telomere maintenance (dyskeratosis congenita), and ribosome biogenesis (Diamond-Blackfan anemia, Shwachman-Diamond syndrome). Somatic mutations leading to clonal hematopoiesis have been described in IBMFS, but the distinct mechanisms by which mutations drive clonal advantage in each disease and their associations with leukemia risk are not well understood. Clinical observations and laboratory models of IBMFS suggest that the germline deficiencies establish a qualitatively impaired functional state at baseline. In this context, somatic alterations can promote clonal hematopoiesis by improving the competitive fitness of specific hematopoietic stem cell clones. Some somatic alterations relieve baseline fitness constraints by normalizing the underlying germline deficit through direct reversion or indirect compensation, while others do so by subverting senescence or tumor suppressor pathways. Clones with normalizing somatic mutations may have limited transformation potential due to retention of functionally intact fitness-sensing and tumor suppressor pathways, while those with mutations that impair cellular elimination may have increased risk of malignant transformation due to subversion of tumor suppressor pathways. Since clonal hematopoiesis is not deterministic of malignant transformation, rational surveillance strategies will thus depend on the ability to prospectively identify specific clones with increased leukemic potential. We describe a framework by which an understanding of the processes that promote clonal hematopoiesis in IBMFS may inform clinical surveillance strategies.

Significance of Telomere Length Measurement in the Diagnosis of Dyskeratosis Congenita.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 836-836
Author(s):  
Hong-Yan Du ◽  
Elena Pumbo ◽  
Akiko Shimamura ◽  
Adrianna Vlachos ◽  
Jeffrey M. Lipton ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Aplastic Anemia ◽  
Telomere Length ◽  
Bone Marrow Failure ◽  
Skin Pigmentation ◽  
Screening Method ◽  
Dyskeratosis Congenita ◽  
Telomere Maintenance ◽  
Healthy Controls ◽  
Mutation Carriers

Abstract Dyskeratosis congenita (DC) is a rare inherited bone marrow failure (BMF) syndrome. The classical features of DC include nail dystrophy, abnormal skin pigmentation, and mucosal leukoplakia. The diagnosis of DC can be difficult. Originally, the diagnosis was based on the presence of the classical mucocutaneous features. However, the identification of four genes responsible for DC (DKC1, TERC, TERT, and NOP10) showed that these mucocutaneous features are only present in a proportion of patients with DC. Additionally, screening for mutations in the affected genes is expensive and is negative in about 50% of patients with classical features of DC. The products of the genes mutated in DC are the components of the telomerase ribonucleoprotein complex, which is essential for telomere maintenance. Therefore it has been postulated that DC is a disease arising from excessive telomere shortening. Here we examined whether the measurement of telomeres could be used as a screening test to identify individuals with DC. For this purpose we examined telomere length in peripheral blood mononuclear cells from 169 patients who presented with bone marrow failure including 17 patients with DC, diagnosed by the presence of classical cutaneous features or the identification of mutations in DKC1, TERC or TERT, 28 patients with paroxysmal nocturnal hemoglobinuria, 25 patients with Diamond Blackfan anemia, 5 patients with Shwachman-Diamond syndrome, 8 patients with myelodysplastic syndrome, and 74 patients with aplastic anemia of unknown cause classified as idiopathic aplastic anemia. In addition we measured telomere length in 12 patients with idiopathic pulmonary fibrosis and in 45 individuals with a de novo deletion of chromosome 5p including the TERT gene. Their telomere lengths were compared with those of 202 age-matched healthy controls. Moreover, mutations were screened in the genes associated with DC. In cases where a mutation was identified, telomere length and mutations were also examined in all the family members. Our results show that all patients with DC and bone marrow failure have very short telomeres far below the first percentile of healthy controls. Not all mutation carriers, including some carriers of apparently dominant mutations, have very short telomeres. What is more, very short telomeres could be found in healthy individuals in these families, some of whom were not mutation carriers. These findings indicate that in patients with BMF the measurement of telomere length is a sensitive screening method for DC, whether very short telomeres in this setting are also specific for DC remains to be determined. However, in contrast to a previous study, we find that telomere length does not always identify mutation carriers in the families of DC.

TERT Mutations in Patients with Squamous Cell Carcinoma of the Tongue and Refractory Anemia

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3096-3096
Author(s):  
Geraldine Aubert ◽  
Mark Hills ◽  
Carol Cremin ◽  
Irma Vulto ◽  
Barbara McGillivray ◽  
...  
Keyword(s):  
Squamous Cell Carcinoma ◽  
Pulmonary Fibrosis ◽  
Cell Carcinoma ◽  
Telomere Length ◽  
Squamous Cell ◽  
Peripheral Blood ◽  
Dyskeratosis Congenita ◽  
Telomere Maintenance ◽  
Refractory Anemia ◽  
Normal Cells

Abstract Dyskeratosis Congenita (DC) is a marrow failure syndrome characterized by skin and nail abnormalities, oral leukoplakia and very short telomeres in circulating leukocytes. Heritable defects in telomere maintenance have been directly implicated in DC by the discovery of mutations in genes encoding components of the telomerase complex: DKC1, TERT, and TERC as well as mutations in the gene encoding the telomere binding protein TINF2. Defective telomeres in DC result in impaired hematopoiesis and predispose to myeloproliferative disorders. Heritable mutations in TERT and TERC have also been implicated in patients presenting with aplastic anemia (AA) and idiopathic pulmonary fibrosis (IPF) without clinical signs of DC. Because short telomeres appear to be associated with increased risks for various human cancers, including head and neck cancer, we sequenced TERT and TERC in two patients with oral carcinoma and anemia. The first patient presented at age 47 with invasive squamous cell carcinoma (SCC) of the tongue. The patient had a male sibling said to be also suffering from SCC which was not available for analysis and his mother died at age 37 from lymphoma. The patient displayed mild macrocytic anemia and oral leukoplakia. The telomere lengths of peripheral blood cells from the patient, determined by flow-FISH, were found to be below the first percentile expected for his age. In contrast, the leukocyte telomere lengths for the patient’s father and a female sibling were within the normal range. Bi-directional sequence analysis of TERT and TERC was conducted on DNA isolated from whole blood for the three family members. A novel mutation in exon 9 of TERT, C842T, situated within the reverse transcriptase domain of the telomerase enzyme catalytic component was identified in the patient but not in the 2 unaffected relatives. This suggested inheritance of a TERT mutation from the mother. The function of TERT C842T was compared to wildtype (WT) TERT by transfecting WT and mutant TERT cDNA into clonal Jurkat T cells and measuring telomere elongation by flow-FISH following 4 weeks of culture. TERT C842T showed 30% of the elongation obtained with WT TERT (p=0.0034). The second patient is a 60 yr old male with SCC of the tongue and refractory anemia with ring sideroblasts. The leukocyte telomere length was around the 1st percentile expected for his age. TERT sequencing revealed a three nucleotide deletion resulting in loss of 441E while retaining frame that is expected to impair telomerase activity. Our data support the concept that mutations in TERT can cause defective telomere maintenance and thereby compromise the proliferation of hematopoietic as well as epithelial cells. The resulting loss of normal cells selects for cells with defective DNA damage checkpoints that are triggered by chromosome ends without telomere repeats. Such cells are at high risk of becoming malignant because their proliferation will be stimulated by the loss of normal cells and their genome is very unstable as telomere function is compromised. Together these factors facilitate and enable clonal evolution of abnormal cells by DNA repair defects and cycles of chromosome fusions/bridge/breakage. Hematological and pathological findings consistent with Dyskeratosis Congenita together with peripheral blood telomere length measurements appear useful parameters to screen for telomere defects in patients and facilitate the discovery of mutations in “telomere maintenance” genes. The TERT mutations in patients with oral carcinomas illustrate that disease manifestations of telomere dysfunction in humans can be very diverse and range from DC, to defective hematopoiesis, pulmonary fibrosis and cancer predisposition.

scholarly journals Very short telomere length by flow fluorescence in situ hybridization identifies patients with dyskeratosis congenita

Blood ◽  
2007 ◽  
Vol 110 (5) ◽  
pp. 1439-1447 ◽  
Author(s):  
Blanche P. Alter ◽  
Gabriela M. Baerlocher ◽  
Sharon A. Savage ◽  
Stephen J. Chanock ◽  
Babette B. Weksler ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
In Situ Hybridization ◽  
Fluorescence In Situ Hybridization ◽  
Telomere Length ◽  
Bone Marrow Failure ◽  
Correct Diagnosis ◽  
Dyskeratosis Congenita ◽  
Telomere Maintenance

Abstract Dyskeratosis congenita (DC) is an inherited bone marrow failure syndrome in which the known susceptibility genes (DKC1, TERC, and TERT) belong to the telomere maintenance pathway; patients with DC have very short telomeres. We used multicolor flow fluorescence in situ hybridization analysis of median telomere length in total blood leukocytes, granulocytes, lymphocytes, and several lymphocyte subsets to confirm the diagnosis of DC, distinguish patients with DC from unaffected family members, identify clinically silent DC carriers, and discriminate between patients with DC and those with other bone marrow failure disorders. We defined “very short” telomeres as below the first percentile measured among 400 healthy control subjects over the entire age range. Diagnostic sensitivity and specificity of very short telomeres for DC were more than 90% for total lymphocytes, CD45RA+/CD20− naive T cells, and CD20+ B cells. Granulocyte and total leukocyte assays were not specific; CD45RA− memory T cells and CD57+ NK/NKT were not sensitive. We observed very short telomeres in a clinically normal family member who subsequently developed DC. We propose adding leukocyte subset flow fluorescence in situ hybridization telomere length measurement to the evaluation of patients and families suspected to have DC, because the correct diagnosis will substantially affect patient management.

scholarly journals Common Variable Immunodeficiency (CVID) in Adults As First Manifestation of (cryptic) Dyskeratosis Congenita

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1217-1217
Author(s):  
Benjamin Rolles ◽  
Alla Bulashevska ◽  
Michele Proietti ◽  
Sigune Goldacker ◽  
Klaus Warnatz ◽  
...  
Keyword(s):  
Common Variable Immunodeficiency ◽  
Research Funding ◽  
Bone Marrow Failure ◽  
Clinical Signs ◽  
Dyskeratosis Congenita ◽  
Adult Patients ◽  
Telomere Maintenance ◽  
Control Group ◽  
Fish Analysis ◽  
Common Variable

Introduction: Dyskeratosis Congenita (DKC) is caused by mutations in genes related to telomere maintenance resulting in prematurely shortened telomeres. Clinically, classical DKC is characterized by mucocutaneous abnormalities, bone marrow failure and other variable features such as lung or liver fibrosis. In adults, mono- or oligosymptomatic DKC is typically presenting with a clinically more heterogeneous and often cryptic picture without classical symptoms of DKC. Data on immunodeficiency as a predominant symptom in DKC patients is limited. The common variable immunodeficiency (CVID) represents a heterogenous group of disease with no universally accepted definition. Typically, patients show hypogammaglobulinaemia and impaired vaccine response. In most cases the genetic basis of CVID remains unknown and to date, the disease is primarily via exclusion of other reasons for hypogammaglobulinaemia. In this study, we aimed to retrospectively analyze the frequency and characteristics of adult patients with altered telomere maintenance (manifesting themselves as "cryptic DKC") within a well-defined cohort of patients with clinical findings of CVID. Materials and Methods: 200 patients of the Freiburg registry of adult CVID patients underwent whole-exome sequencing (WES). Diagnosis of CVID was established based on the recommendations of the European Society of Immune Deficiencies. Retrospectively, all patients were screened for mutations/variants in the following DKC causing genes: TERT, RTEL1, DKC1, NHP2, TERC, NOP10, TCAB1, TIN2 and CTC1. Screening identified 23 patients (age: 45 +/- 13 years; mean +/- S.D.) with mutations/polymorphisms in these genes. All identified variants were heterozygous. One patient showed polymorphisms in three different genes. To analyze the functional consequences on telomere maintenance, telomere length (TL) of peripheral blood mononuclear cells (PBMCs) were analyzed via MM-Q-PCR in all 23 patients. Furthermore, Flow-FISH analysis of lymphocytes as well as granulocytes was carried out in 22 and 14 patients, respectively. Results: TL analysis measured with MM-Q-PCR showed in most of the 23 patients shortened TL compared to an age-matched control group. We measured premature TL shortening below the 1% percentile in 44% (10/23) and below the 10% percentile in 52% (12/23). TL determined via flow-FISH showed TL in lymphocytes below the 10% percentile in 64% (14/22) and below 1% in 27% (6/22). WES revealed 24 polymorphisms/mutations in RTEL1 (n=5), TERT (n=3), NHP2 (n=6), DKC1 (n=8) and CTC1 (n=2). Based on bioinformatic prediction, 78 % (19/24) of all polymorphisms were classified as likely benign variants. Two patients with pathogenic mutations were identified: One 30 year old patient with previously described pathogenic TERT mutation (c.1234C>T, p.His412Tyr) was identified showing lymphocyte and granulocyte TL with flow-FISH between the 1% and 10% percentile and below the 1% percentile using MM-Q-PCR. One 23 year old patient with a bioinformatic predicted pathogenic mutation in RTEL1 (c.2313_2315delAGA, p.Glu771del) showed TL in flow-FISH and MM-Q-PCR below the 1% percentile. Of note, this patient developed few years after initial CVID diagnosis severe interstitial lung disease. Three patients were identified with possible DKC showing variants of unknown significance in the RTEL1 (41 years: c.380G>A, p.Arg127Gln) and TERT (65 years: c.3257G>A, p.Arg1086His and 42 years: c.1843G>A, p.Ala615Thr) gene having both TL in lymphocytes/granulocytes (flow-FISH) and leukocytes (MM-Q-PCR) below the 5% percentile. Conclusions: Clinical signs of immunodeficiency can be a rare first manifestation of cryptic/late-onset DKC in adult patients. We found out that at least 1% of all patients with CVID syndrome is caused by mutations typically found in DKC. Our data adds a further important clinical manifestation to the broad clinical spectrum of cryptic DKC. In return, awareness of CVID as a possible first manifestation of cryptic DKC can improve patient management. TL analysis in addition to genetic work-up provides a valuable tool to identify DKC as underlying disease of CVID and other disorders characterized by impaired replicative potential. Disclosures Brümmendorf: Ariad: Consultancy; Merck: Consultancy; University Hospital of the RWTH Aachen: Employment; Pfizer: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Janssen: Consultancy. Beier:Novartis: Honoraria; Repeat Dx: Other: Partner.

scholarly journals Dyskerin Is a Component of the Arabidopsis Telomerase RNP Required for Telomere Maintenance

2008 ◽  
Vol 28 (7) ◽  
pp. 2332-2341 ◽  
Author(s):  
Kalpana Kannan ◽  
Andrew D. L. Nelson ◽  
Dorothy E. Shippen
Keyword(s):  
Telomere Length ◽  
Bone Marrow Failure ◽  
Telomerase Activity ◽  
Dyskeratosis Congenita ◽  
Dominant Negative ◽  
Telomere Maintenance ◽  
Dependent Manner ◽  
Missense Mutations

ABSTRACT Dyskerin binds the H/ACA box of human telomerase RNA and is a core telomerase subunit required for RNP biogenesis and enzyme function in vivo. Missense mutations in dyskerin result in dyskeratosis congenita, a complex syndrome characterized by bone marrow failure, telomerase enzyme deficiency, and progressive telomere shortening. Here we demonstrate that dyskerin also contributes to telomere maintenance in Arabidopsis thaliana. We report that both AtNAP57, the Arabidopsis dyskerin homolog, and AtTERT, the telomerase catalytic subunit, accumulate in the plant nucleolus, and AtNAP57 associates with active telomerase RNP particles in an RNA-dependent manner. Furthermore, AtNAP57 interacts in vitro with AtPOT1a, a novel component of Arabidopsis telomerase. Although a null mutation in AtNAP57 is lethal, AtNAP57, like AtTERT, is not haploinsufficient for telomere maintenance in Arabidopsis. However, introduction of an AtNAP57 allele containing a T66A mutation decreased telomerase activity in vitro, disrupted telomere length regulation on individual chromosome ends in vivo, and established a new, shorter telomere length set point. These results imply that T66A NAP57 behaves as a dominant-negative inhibitor of telomerase. We conclude that dyskerin is a conserved component of the telomerase RNP complex in higher eukaryotes that is required for maximal enzyme activity in vivo.

scholarly journals The Presence of MDS-like Phenotypic Abnormalities (MDS-PA) Identifies Newly Diagnosed Multiple Myeloma (MM) Patients with MDS/AML-Related Somatic Mutations and Inferior Survival

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 375-375
Author(s):  
Bruno Paiva ◽  
Noemi Puig ◽  
Maria Teresa Cedena ◽  
Iria Vazquez ◽  
Carmen Chillon ◽  
...  
Keyword(s):  
Research Funding ◽  
Somatic Mutations ◽  
Prognostic Significance ◽  
Hematological Toxicity ◽  
Erythroid Cells ◽  
Newly Diagnosed ◽  
Similar Frequency ◽  
Hematopoietic Stem ◽  
Increased Risk

Abstract MM patients are living longer with increasingly effective therapies, but long-term complications including second primary malignancies (SPMs) are becoming new challenges in designing optimal patient care. It has been demonstrated in large studies that amongst others, risk is particularly high for SPMs such as myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). Importantly, such increased risk of MDS/AML has also been observed in MGUS patients, suggesting that increased risk for MDS/AML may not only be treatment related but inheritably high in MGUS/MM. Thus, there is need to investigate for biomarkers that uncover cellular alterations predisposing for higher risk of MDS/AML in MM. Here, we started by investigating in 312 newly diagnosed MM patients the presence of MDS-like phenotypic abnormalities (MDS-PA) in bone marrow (BM) neutrophil, monocytic, and erythroid lineages, using multidimensional flow cytometry 8 color combinations (CD138, CD27, CD38, CD56, CD45, CD19, CD117, CD81; and HLADR, CD45, CD36, CD13, CD34, CD117, CD11b, CD71). Up to 33/312 (11%) patients showed MDS-PA at diagnosis, which were more frequently observed in the neutrophil lineage (6%), followed by monocytic (4%) and erythroid (4%) lineages. Four cases had multilineage MDS-PA. Afterwards, we investigated if the presence of MDS-PA was associated with underlying somatic mutations by performing targeted sequencing of 54 MDS/AML related genes (depth ≥500x) in 44 patients from the previous series (10 with MDS-PA and 34 without). Next generation sequencing was performed, at diagnosis and after HDT/ASCT in FACS sorted CD34+ hematopoietic stem cells (HSCs) and dysplastic cell lineages from patients with MDS-PA, as well as in HSC from cases without MDS-PA. CD138+ BM plasma cells (PCs) from both cohorts were also sequenced using the same panel. Six out of the 10 cases with MDS-PA showed somatic mutations. Namely, HSCs from one patient had two mutations in TET2 [allele fraction (AF): 18%, ≥ 26017x] one in CALR (AF: 14%, 1158x) and another in ASXL1 (AF: 7%, 1339x). None of these mutations were present in myeloid/erythroid cells. A second patient had NPM1 mutated in HSCs (AF: 7%, 12825x), which was absent in neutrophils. A third case had TET2 mutated in HSCs (AF: 16%, 1233x) as well as in dysplastic monocytes (AF: 27%, 16647x) and neutrophils (AF: 23%, 21719x). In the fourth case, a mutation in BCORL1 was noted in dysplastic erythroid cells (AF: 10%, 796x). The fifth patient had TET2 mutated in both HSCs and dysplastic monocytes (AF: 45%-63%; ≥21799x). The sixth case had PHF6 mutated in HSCs (AF: 8%; 800x). In none of the patients were the mutations found in HSCs and/or dysplastic lineages, present in PCs. Within the control cohort of the 34 patients without MDS-PA, only two of them displayed somatic mutations in HSCs; one case had DNMT3A mutated (AF: 26%, 1900x) and the other TET2 (AF: 13%, 3400x). After demonstrating a correlation between MDS-PA and MDS/AML-related somatic mutations, we sought to analyze the prognostic significance of such alterations in MM. Since the follow-up of the present series of 312 cases is relatively short, we focused on a large series of 965 patients with longer follow up (median of 6.5 years) enrolled in GEM clinical trials, and for which the presence of CD56+ aberrant monocytes could be readily investigated. Noteworthy, this particular MDS-PA was again observed in a similar frequency as noted above (n=63; 6.5%) and as compared to the overall MM population, patients with MDS-PA showed significantly higher age, lower hemoglobin values and higher BMPC infiltration at diagnosis. Furthermore, they experienced more frequently hematological toxicity including anemia and neutropenia during treatment. Most interestingly, as compared to the overall MM population, patients with MDS-PA had significantly inferior progression-free (medians of 24 vs 37 months; P=.006) and overall survival (medians of 47 vs 73 months; P=.01). In conclusion, we showed for the first time that a fraction of newly diagnosed MM patients harbors MDS/AML-related somatic mutations in HSCs and myeloid/erythroid lineages, and that such patients could be predicted through flow-based screening for MDS-PA. The presence of MDS-PA identifies a subset of patients that experience more frequently hematological toxicity and display inferior survival; accordingly, screening for MDS-PA could become an important biomarker to tailor treatment in MM. Disclosures Paiva: Celgene: Honoraria, Research Funding; Janssen: Honoraria; Takeda: Honoraria, Research Funding; Sanofi: Consultancy, Research Funding; EngMab: Research Funding; Amgen: Honoraria; Binding Site: Research Funding. Oriol:Amgen: Honoraria, Other: Expert board committee; Janssen: Honoraria, Other: Expert board committee. Mateos:Amgen: Honoraria; Takeda: Honoraria; Celgene: Honoraria; Janssen: Honoraria.

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