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Suspitsin E, Eliseyeva D, Chiryaeva O, Belogubova E, Aleksakhina S, Sokolenko A, Imyanitov E. Asymptomatic Bloom syndrome diagnosed by chance in a patient with breast cancer. Fam Cancer 2024:10.1007/s10689-024-00420-0. [PMID: 39240481 DOI: 10.1007/s10689-024-00420-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2024] [Accepted: 09/01/2024] [Indexed: 09/07/2024]
Abstract
Bloom syndrome (BS) is a rare genetic disorder caused by biallelic inactivation of the BLM gene, which usually manifests in childhood by significant growth retardation, immune deficiency, characteristic skin lesions, cancer predisposition and other distinguishable disease features. To our knowledge, all prior instances of BS have been identified via intentional analysis of patients with clinical suspicion for this disease or DNA testing of members of affected pedigrees. We describe an incidental finding of BS, which occurred upon routine germline DNA analysis of consecutive breast cancer patients. The person with the biallelic pathogenic BLM c.1642C>T (p.Gln548Ter) variant remained clinically healthy for 38 years until she developed breast cancer. Detailed examination of this woman, which was carried out after the genetic diagnosis, revealed mild features of BS. A sister chromatid exchange (SCE) test confirmed the presence of this syndrome. The tumor exhibited triple-negative receptor status, a high proliferation rate, a low tumor mutation burden (TMB), and a moderate level of chromosomal instability (homologous recombination deficiency (HRD) score = 29). The patient showed normal tolerability to radiotherapy and several regimens of cytotoxic therapy. Thus, some BS patients may remain undiagnosed due to the mild phenotype of their disease. BLM should be incorporated in gene panels utilized for germline DNA testing of cancer patients.
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Affiliation(s)
- Evgeny Suspitsin
- Department of Tumor Growth Biology, N.N. Petrov Institute of Oncology, Saint-Petersburg, Russia
- Department of Medical Genetics, St. Petersburg State Pediatric Medical University, St. Petersburg, Russia
| | | | - Olga Chiryaeva
- Department of Medical Genetics, St. Petersburg State Pediatric Medical University, St. Petersburg, Russia
- D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, St.-Petersburg, Russia
| | - Evgeniya Belogubova
- Department of Tumor Growth Biology, N.N. Petrov Institute of Oncology, Saint-Petersburg, Russia
| | - Svetlana Aleksakhina
- Department of Tumor Growth Biology, N.N. Petrov Institute of Oncology, Saint-Petersburg, Russia
| | - Anna Sokolenko
- Department of Tumor Growth Biology, N.N. Petrov Institute of Oncology, Saint-Petersburg, Russia.
- Department of Medical Genetics, St. Petersburg State Pediatric Medical University, St. Petersburg, Russia.
| | - Evgeny Imyanitov
- Department of Tumor Growth Biology, N.N. Petrov Institute of Oncology, Saint-Petersburg, Russia
- Department of Medical Genetics, St. Petersburg State Pediatric Medical University, St. Petersburg, Russia
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Pallenberg ST, Held I, Dopfer C, Minso R, Nietert MM, Hansen G, Tümmler B, Dittrich AM. Differential effects of ELX/TEZ/IVA on organ-specific CFTR function in two patients with the rare CFTR splice mutations c.273+1G>A and c.165-2A>G. Front Pharmacol 2023; 14:1153656. [PMID: 37050906 PMCID: PMC10083416 DOI: 10.3389/fphar.2023.1153656] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Accepted: 03/15/2023] [Indexed: 03/28/2023] Open
Abstract
Introduction: Evidence for the efficiency of highly-effective triple-CFTR-modulatory therapy with elexacaftor/tezacaftor/ivacaftor (ETI), either demonstrated in clinical trials or by in vitro testing, is lacking for about 10% of people with cystic fibrosis (pwCF) with rare mutations. Comprehensive assessment of CFTR function can provide critical information on the impact of ETI on CFTR function gains for such rare mutations, lending argument of the prescription of ETI. The mutation c.165-2A>G is a rare acceptor splice mutation that has not yet been functionally characterized. We here describe the functional changes induced by ETI in two brothers who are compound heterozygous for the splice mutations c.273+1G>C and c.165-2A>G.Methods: We assessed the effects of ETI on CFTR function by quantitative pilocarpine iontophoresis (QPIT), nasal potential difference measurements (nPD), intestinal current measurements (ICM), β-adrenergic sweat secretion tests (SST) and multiple breath washout (MBW) prior to and 4 months after the initiation of ETI.Results: Functional CFTR analysis prior to ETI showed no CFTR function in the respiratory and intestinal epithelia and in the sweat gland reabsorptive duct in either brother. In contrast, β-adrenergic stimulated, CFTR-mediated sweat secretion was detectable in the CF range. Under ETI, both brothers continued to exhibit high sweat chloride concentration in QPIT, evidence of low residual CFTR function in the respiratory epithelia, but normalized β-adrenergically stimulated production of primary sweat.Discussion: Our results are the first to demonstrate that the c.165-2A>G/c.273+1G>C mutation genotype permits mutant CFTR protein expression. We showed organ-specific differences in the expression of CFTR and consecutive responses to ETI of the c.165-2A>G/c.273+1G>C CFTR mutants that are probably accomplished by non-canonical CFTR mRNA isoforms. This showcase tells us that the individual response of rare CFTR mutations to highly-effective CFTR modulation cannot be predicted from assays in standard cell cultures, but requires the personalized multi-organ assessment by CFTR biomarkers.
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Affiliation(s)
- Sophia T. Pallenberg
- Department of Pediatric Pneumology, Allergology and Neonatology, Hannover Medical School, Hannover, Germany
- German Center for Lung Research, Biomedical Research in Endstage and Obstructive Lung Disease (BREATH), Hannover Medical School, Hannover, Germany
- *Correspondence: Sophia T. Pallenberg,
| | - Inka Held
- Kinderärzte Friesenweg—CF-Zentrum Altona (Ambulanz), Hamburg, Germany
| | - Christian Dopfer
- Department of Pediatric Pneumology, Allergology and Neonatology, Hannover Medical School, Hannover, Germany
| | - Rebecca Minso
- Department of Pediatric Pneumology, Allergology and Neonatology, Hannover Medical School, Hannover, Germany
- German Center for Lung Research, Biomedical Research in Endstage and Obstructive Lung Disease (BREATH), Hannover Medical School, Hannover, Germany
| | - Manuel M. Nietert
- Department of Medical Bioinformatics, University Medical Center Göttingen, Göttingen, Germany
| | - Gesine Hansen
- Department of Pediatric Pneumology, Allergology and Neonatology, Hannover Medical School, Hannover, Germany
- German Center for Lung Research, Biomedical Research in Endstage and Obstructive Lung Disease (BREATH), Hannover Medical School, Hannover, Germany
| | - Burkhard Tümmler
- Department of Pediatric Pneumology, Allergology and Neonatology, Hannover Medical School, Hannover, Germany
- German Center for Lung Research, Biomedical Research in Endstage and Obstructive Lung Disease (BREATH), Hannover Medical School, Hannover, Germany
| | - Anna-Maria Dittrich
- Department of Pediatric Pneumology, Allergology and Neonatology, Hannover Medical School, Hannover, Germany
- German Center for Lung Research, Biomedical Research in Endstage and Obstructive Lung Disease (BREATH), Hannover Medical School, Hannover, Germany
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Rossi A, Kontarakis Z. Beyond Mendelian Inheritance: Genetic Buffering and Phenotype Variability. PHENOMICS (CHAM, SWITZERLAND) 2022; 2:79-87. [PMID: 36939776 PMCID: PMC9590499 DOI: 10.1007/s43657-021-00030-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 09/29/2021] [Accepted: 10/08/2021] [Indexed: 06/18/2023]
Abstract
Understanding the way genes work amongst individuals and across generations to shape form and function is a common theme for many genetic studies. The recent advances in genetics, genome engineering and DNA sequencing reinforced the notion that genes are not the only players that determine a phenotype. Due to physiological or pathological fluctuations in gene expression, even genetically identical cells can behave and manifest different phenotypes under the same conditions. Here, we discuss mechanisms that can influence or even disrupt the axis between genotype and phenotype; the role of modifier genes, the general concept of genetic redundancy, genetic compensation, the recently described transcriptional adaptation, environmental stressors, and phenotypic plasticity. We furthermore highlight the usage of induced pluripotent stem cells (iPSCs), the generation of isogenic lines through genome engineering, and sequencing technologies can help extract new genetic and epigenetic mechanisms from what is hitherto considered 'noise'.
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Affiliation(s)
- Andrea Rossi
- Genome Engineering and Model Development Lab (GEMD), IUF-Leibniz Research Institute for Environmental Medicine, 40225 Düsseldorf, Germany
| | - Zacharias Kontarakis
- Genome Engineering and Measurement Laboratory (GEML), Eidgenössische Technische Hochschule (ETH) Zurich, Zurich, Switzerland
- Functional Genomics Center Zurich of ETH Zurich, University of Zurich, 8093 Zurich, Switzerland
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