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Wang L, Bu T, Wu X, Li L, Sun F, Cheng CY. Motor proteins, spermatogenesis and testis function. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2024; 141:381-445. [PMID: 38960481 DOI: 10.1016/bs.apcsb.2024.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
The role of motor proteins in supporting intracellular transports of vesicles and organelles in mammalian cells has been known for decades. On the other hand, the function of motor proteins that support spermatogenesis is also well established since the deletion of motor protein genes leads to subfertility and/or infertility. Furthermore, mutations and genetic variations of motor protein genes affect fertility in men, but also a wide range of developmental defects in humans including multiple organs besides the testis. In this review, we seek to provide a summary of microtubule and actin-dependent motor proteins based on earlier and recent findings in the field. Since these two cytoskeletons are polarized structures, different motor proteins are being used to transport cargoes to different ends of these cytoskeletons. However, their involvement in germ cell transport across the blood-testis barrier (BTB) and the epithelium of the seminiferous tubules remains relatively unknown. It is based on recent findings in the field, we have provided a hypothetical model by which motor proteins are being used to support germ cell transport across the BTB and the seminiferous epithelium during the epithelial cycle of spermatogenesis. In our discussion, we have highlighted the areas of research that deserve attention to bridge the gap of research in relating the function of motor proteins to spermatogenesis.
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Affiliation(s)
- Lingling Wang
- The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, P.R. China; Department of Urology and Andrology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China
| | - Tiao Bu
- Department of Urology and Andrology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China
| | - Xiaolong Wu
- Department of Urology and Andrology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China
| | - Linxi Li
- The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, P.R. China
| | - Fei Sun
- Department of Urology and Andrology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China
| | - C Yan Cheng
- The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, P.R. China; Department of Urology and Andrology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China.
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2
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Blasius TL, Yue Y, Prasad R, Liu X, Gennerich A, Verhey KJ. Sequences in the stalk domain regulate auto-inhibition and ciliary tip localization of the immotile kinesin-4 KIF7. J Cell Sci 2021; 134:269104. [PMID: 34114033 DOI: 10.1242/jcs.258464] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 05/27/2021] [Indexed: 12/31/2022] Open
Abstract
The kinesin-4 member KIF7 plays critical roles in Hedgehog signaling in vertebrate cells. KIF7 is an atypical kinesin as it binds to microtubules but is immotile. We demonstrate that, like conventional kinesins, KIF7 is regulated by auto-inhibition, as the full-length protein is inactive for microtubule binding in cells. We identify a segment, the inhibitory coiled coil (inhCC), that is required for auto-inhibition of KIF7, whereas the adjacent regulatory coiled coil (rCC) that contributes to auto-inhibition of the motile kinesin-4s KIF21A and KIF21B is not sufficient for KIF7 auto-inhibition. Disease-associated mutations in the inhCC relieve auto-inhibition and result in strong microtubule binding. Surprisingly, uninhibited KIF7 proteins did not bind preferentially to or track the plus ends of growing microtubules in cells, as suggested by previous in vitro work, but rather bound along cytosolic and axonemal microtubules. Localization to the tip of the primary cilium also required the inhCC, and could be increased by disease-associated mutations regardless of the auto-inhibition state of the protein. These findings suggest that loss of KIF7 auto-inhibition and/or altered cilium tip localization can contribute to the pathogenesis of human disease.
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Affiliation(s)
- T Lynne Blasius
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Yang Yue
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - RaghuRam Prasad
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Xinglei Liu
- Department of Anatomy and Structural Biology and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, New York, NY 10461, USA
| | - Arne Gennerich
- Department of Anatomy and Structural Biology and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, New York, NY 10461, USA
| | - Kristen J Verhey
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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3
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Massa F, Tammaro R, Prado MA, Cesana M, Lee BH, Finley D, Franco B, Morleo M. The deubiquitinating enzyme Usp14 controls ciliogenesis and Hedgehog signaling. Hum Mol Genet 2020; 28:764-777. [PMID: 30388222 DOI: 10.1093/hmg/ddy380] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 10/11/2018] [Accepted: 10/16/2018] [Indexed: 12/20/2022] Open
Abstract
Primary cilia are hair-like organelles that play crucial roles in vertebrate development, organogenesis and when dysfunctional result in pleiotropic human genetic disorders called ciliopathies, characterized by overlapping phenotypes, such as renal and hepatic cysts, skeletal defects, retinal degeneration and central nervous system malformations. Primary cilia act as communication hubs to transfer extracellular signals into intracellular responses and are essential for Hedgehog (Hh) signal transduction in mammals. Despite the renewed interest in this ancient organelle of growing biomedical importance, the molecular mechanisms that trigger cilia formation, extension and ciliary signal transduction are still not fully understood. Here we provide, for the first time, evidence that the deubiquitinase ubiquitin-specific protease-14 (Usp14), a major regulator of the ubiquitin proteasome system (UPS), controls ciliogenesis, cilia elongation and Hh signal transduction. Moreover, we show that pharmacological inhibition of Usp14 positively affects Hh signal transduction in a model of autosomal dominant polycystic kidney disease. These findings provide new insight into the spectrum of action of UPS in cilia biology and may provide novel opportunities for therapeutic intervention in human conditions associated with ciliary dysfunction.
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Affiliation(s)
- Filomena Massa
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, Pozzuoli, Naples, Italy
| | - Roberta Tammaro
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, Pozzuoli, Naples, Italy
| | - Miguel A Prado
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Marcella Cesana
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, Pozzuoli, Naples, Italy
| | - Byung-Hoon Lee
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA.,Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology, Daegu, Korea
| | - Daniel Finley
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Brunella Franco
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, Pozzuoli, Naples, Italy.,Medical Genetics, Department of Translational Medicine, University of Naples Federico II, Via Sergio Pansini 5, Naples, Italy
| | - Manuela Morleo
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, Pozzuoli, Naples, Italy.,Medical Genetics, Department of Translational Medicine, University of Naples Federico II, Via Sergio Pansini 5, Naples, Italy
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4
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Chen Y, Renfree MB. Hormonal and Molecular Regulation of Phallus Differentiation in a Marsupial Tammar Wallaby. Genes (Basel) 2020; 11:genes11010106. [PMID: 31963388 PMCID: PMC7017150 DOI: 10.3390/genes11010106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 12/24/2019] [Accepted: 01/14/2020] [Indexed: 11/16/2022] Open
Abstract
Congenital anomalies in phalluses caused by endocrine disruptors have gained a great deal of attention due to its annual increasing rate in males. However, the endocrine-driven molecular regulatory mechanism of abnormal phallus development is complex and remains largely unknown. Here, we review the direct effect of androgen and oestrogen on molecular regulation in phalluses using the marsupial tammar wallaby, whose phallus differentiation occurs after birth. We summarize and discuss the molecular mechanisms underlying phallus differentiation mediated by sonic hedgehog (SHH) at day 50 pp and phallus elongation mediated by insulin-like growth factor 1 (IGF1) and insulin-like growth factor binding protein 3 (IGFBP3), as well as multiple phallus-regulating genes expressed after day 50 pp. We also identify hormone-responsive long non-coding RNAs (lncRNAs) that are co-expressed with their neighboring coding genes. We show that the activation of SHH and IGF1, mediated by balanced androgen receptor (AR) and estrogen receptor 1 (ESR1) signalling, initiates a complex regulatory network in males to constrain the timing of phallus differentiation and to activate the downstream genes that maintain urethral closure and phallus elongation at later stages.
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Affiliation(s)
- Yu Chen
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL 32603, USA
- School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia
- Correspondence: (Y.C.); (M.B.R.)
| | - Marilyn B. Renfree
- School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia
- Correspondence: (Y.C.); (M.B.R.)
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5
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Mohanty HS, Shirodkar KK, Sharma N, Bind MK, Nandikoor S. Intracranial cystic lesions and polydactyly associated with acrocallosal syndrome: Sonographic findings in two cases. JOURNAL OF CLINICAL ULTRASOUND : JCU 2019; 47:497-500. [PMID: 31318057 DOI: 10.1002/jcu.22761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 03/16/2019] [Accepted: 07/09/2019] [Indexed: 06/10/2023]
Abstract
We describe two cases of intracranial cystic lesions associated with acrocallosal syndrome. These fetal anomalies were detected on antenatal sonography and confirmed postnatally. Imaging findings include corpus callosum agenesis with interhemispheric cysts and craniofacial anomalies associated with polydactyly. Identifying the above imaging features is of importance to plan management and provide supportive care that may be required.
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Affiliation(s)
- Himansu S Mohanty
- Department of Radiology, Hamdard Imaging Center, Hamdard Institute of Medical Sciences & Research, New Delhi, India
| | | | - Nikhil Sharma
- Department of Radiology, Hamdard Imaging Center, Hamdard Institute of Medical Sciences & Research, New Delhi, India
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6
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Tabler JM, Rigney MM, Berman GJ, Gopalakrishnan S, Heude E, Al-Lami HA, Yannakoudakis BZ, Fitch RD, Carter C, Vokes S, Liu KJ, Tajbakhsh S, Egnor SR, Wallingford JB. Cilia-mediated Hedgehog signaling controls form and function in the mammalian larynx. eLife 2017; 6. [PMID: 28177282 PMCID: PMC5358977 DOI: 10.7554/elife.19153] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 02/06/2017] [Indexed: 12/30/2022] Open
Abstract
Acoustic communication is fundamental to social interactions among animals, including humans. In fact, deficits in voice impair the quality of life for a large and diverse population of patients. Understanding the molecular genetic mechanisms of development and function in the vocal apparatus is thus an important challenge with relevance both to the basic biology of animal communication and to biomedicine. However, surprisingly little is known about the developmental biology of the mammalian larynx. Here, we used genetic fate mapping to chart the embryological origins of the tissues in the mouse larynx, and we describe the developmental etiology of laryngeal defects in mice with disruptions in cilia-mediated Hedgehog signaling. In addition, we show that mild laryngeal defects correlate with changes in the acoustic structure of vocalizations. Together, these data provide key new insights into the molecular genetics of form and function in the mammalian vocal apparatus. DOI:http://dx.doi.org/10.7554/eLife.19153.001 Nearly all animals communicate using sound. In many cases these sounds are in the form of a voice, which in mammals is generated by a specialized organ in the throat called the larynx. Millions of people throughout the world have voice defects that make it difficult for them to communicate. Such defects are distinct from speech defects such as stuttering, and instead result from an inability to control the pitch or volume of the voice. This has a huge impact because our voice is so central to our quality of life. A wide range of human birth defects that are caused by genetic mutations are known to result in voice problems. These include disorders in which the Hedgehog signaling pathway, which allows cells to exchange information, is defective. Projections called cilia that are found on the outside of many cells transmit Hedgehog signals, and birth defects that affect the cilia (called ciliopathies) also often result in voice problems. Although the shape of the larynx has a crucial effect on voice, relatively little is known about how it develops in embryos. Mice are often studied to investigate how human embryos develop. By studying mouse embryos that had genetic mutations similar to those seen in humans with ciliopathies, Tabler, Rigney et al. now show that many different tissues interact in complex ways to form the larynx. A specific group of cells known as the neural crest was particularly important. The neural crest helps to form the face and skull and an excess of these cells causes face and skull defects in individuals with ciliopathies. Tabler, Rigney et al. show that having too many neural crest cells can also contribute towards defects in the larynx of mice with ciliopathies, despite the larynx being in the neck. Further investigation showed that the Hedgehog signaling pathway was required for the larynx to develop properly. Furthermore, recordings of the vocalizations of the mutant mice showed that they had defective voices, thus linking the defects in the shape of the larynx with changes in the vocalizations that the mice made. Overall, Tabler, Rigney et al. show that mice can be used to investigate how the genes that control the shape of the larynx affect the voice. The next step will be to use mice to investigate other genetic defects that cause voice defects in humans. Further research in other animals could also help us to understand how the larynx has evolved. DOI:http://dx.doi.org/10.7554/eLife.19153.002
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Affiliation(s)
- Jacqueline M Tabler
- Department of Molecular Biosciences, University of Texas at Austin, Austin, United States
| | - Maggie M Rigney
- Department of Molecular Biosciences, University of Texas at Austin, Austin, United States
| | - Gordon J Berman
- Department of Biology, Emory University, Atlanta, United States
| | - Swetha Gopalakrishnan
- Stem Cells and Development, CNRS UMR3738, Department of Developmental and Stem Cell Biology, Institut Pasteur, Paris, France
| | - Eglantine Heude
- Stem Cells and Development, CNRS UMR3738, Department of Developmental and Stem Cell Biology, Institut Pasteur, Paris, France
| | - Hadeel Adel Al-Lami
- Department of Craniofacial Development and Stem Cell Biology, King's College London, London, United Kingdom
| | - Basil Z Yannakoudakis
- Department of Craniofacial Development and Stem Cell Biology, King's College London, London, United Kingdom
| | - Rebecca D Fitch
- Department of Molecular Biosciences, University of Texas at Austin, Austin, United States
| | - Christopher Carter
- Department of Molecular Biosciences, University of Texas at Austin, Austin, United States
| | - Steven Vokes
- Department of Molecular Biosciences, University of Texas at Austin, Austin, United States
| | - Karen J Liu
- Department of Craniofacial Development and Stem Cell Biology, King's College London, London, United Kingdom
| | - Shahragim Tajbakhsh
- Stem Cells and Development, CNRS UMR3738, Department of Developmental and Stem Cell Biology, Institut Pasteur, Paris, France
| | - Se Roian Egnor
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United states
| | - John B Wallingford
- Department of Molecular Biosciences, University of Texas at Austin, Austin, United States
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7
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He M, Agbu S, Anderson KV. Microtubule Motors Drive Hedgehog Signaling in Primary Cilia. Trends Cell Biol 2017; 27:110-125. [PMID: 27765513 PMCID: PMC5258846 DOI: 10.1016/j.tcb.2016.09.010] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 09/08/2016] [Accepted: 09/23/2016] [Indexed: 01/05/2023]
Abstract
The mammalian Hedgehog (Hh) signaling pathway is required for development and for maintenance of adult stem cells, and overactivation of the pathway can cause tumorigenesis. All responses to Hh family ligands in mammals require the primary cilium, an ancient microtubule-based organelle that extends from the cell surface. Genetic studies in mice and humans have defined specific functions for cilium-associated microtubule motor proteins: they act in the construction and disassembly of the primary cilium, they control ciliary length and stability, and some have direct roles in mammalian Hh signal transduction. These studies highlight how integrated genetic and cell biological studies can define the molecular mechanisms that underlie cilium-associated health and disease.
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Affiliation(s)
- Mu He
- Department of Physiology and Department of Biochemistry and Biophysics, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Stephanie Agbu
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA; Biochemistry, Cell, and Molecular Biology Program, Weill Graduate School of Medical Sciences of Cornell University, 1300 York Avenue, New York, NY 10065, USA
| | - Kathryn V Anderson
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA.
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8
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Poretti A, Snow J, Summers AC, Tekes A, Huisman TAGM, Aygun N, Carson KA, Doherty D, Parisi MA, Toro C, Yildirimli D, Vemulapalli M, Mullikin JC, Cullinane AR, Vilboux T, Gahl WA, Gunay-Aygun M. Joubert syndrome: neuroimaging findings in 110 patients in correlation with cognitive function and genetic cause. J Med Genet 2017; 54:521-529. [PMID: 28087721 DOI: 10.1136/jmedgenet-2016-104425] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 12/09/2016] [Accepted: 12/10/2016] [Indexed: 12/31/2022]
Abstract
BACKGROUND Joubert syndrome is a clinically and genetically heterogeneous ciliopathy. Neuroimaging findings have not been systematically evaluated in a large cohort of patients with Joubert syndrome in correlation with molecular genetic cause and cognitive function. METHODS Brain MRI of 110 patients with Joubert syndrome was included in this study. A comprehensive evaluation of brain MRI studies for infratentorial and supratentorial morphological abnormalities was performed. Genetic cause was identified by whole-exome sequencing, and cognitive functions were assessed with age-appropriate neurocognitive tests in a subset of patients. RESULTS The cerebellar hemispheres were enlarged in 18% of the patients, mimicking macrocerebellum. The posterior fossa was enlarged in 42% of the patients, resembling Dandy-Walker malformation. Abnormalities of the brainstem, such as protuberance at the ventral contour of the midbrain, were present in 66% of the patients. Abnormalities of the supratentorial brain were present in approximately one-third of the patients, most commonly malrotation of the hippocampi. Mild ventriculomegaly, which typically did not require shunting, was present in 23% of the patients. No correlation between neuroimaging findings and molecular genetic cause was apparent. A novel predictor of outcome was identified; the more severe the degree of vermis hypoplasia, the worse the neurodevelopmental outcome was. CONCLUSIONS The spectrum of neuroimaging findings in Joubert syndrome is wide. Neuroimaging does not predict the genetic cause, but may predict the neurodevelopmental outcome. A high degree of vermis hypoplasia correlates with worse neurodevelopmental outcome. This finding is important for prognostic counselling in Joubert syndrome.
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Affiliation(s)
- Andrea Poretti
- Section of Pediatric Neuroradiology, Division of Pediatric Radiology, Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Department of Neurogenetics, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Joseph Snow
- Intramural Research Program, Office of the Clinical Director, National Institute of Mental Health, National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Angela C Summers
- Intramural Research Program, Office of the Clinical Director, National Institute of Mental Health, National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Aylin Tekes
- Section of Pediatric Neuroradiology, Division of Pediatric Radiology, Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Thierry A G M Huisman
- Section of Pediatric Neuroradiology, Division of Pediatric Radiology, Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Nafi Aygun
- Division of Neuroradiology, Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Kathryn A Carson
- Department of Epidemiology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.,Division of General Internal Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Dan Doherty
- Department of Pediatrics, University of Washington, Seattle, Washington, USA.,Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Melissa A Parisi
- Intellectual and Developmental Disabilities Branch, National Institute of Child Health and Human Development, NIH, Bethesda, Maryland, USA
| | - Camilo Toro
- NIH Undiagnosed Diseases Program, Common Fund, Office of the Director, NIH, Maryland, USA
| | - Deniz Yildirimli
- Medical Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, Maryland, USA
| | - Meghana Vemulapalli
- NIH Intramural Sequencing Center, National Human Genome Research Institute, NIH, Bethesda, Maryland, USA
| | - Jim C Mullikin
- NIH Intramural Sequencing Center, National Human Genome Research Institute, NIH, Bethesda, Maryland, USA
| | | | - Andrew R Cullinane
- Medical Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, Maryland, USA.,Department of Anatomy, Howard University College of Medicine, Washington District of Columbia, USA
| | - Thierry Vilboux
- Medical Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, Maryland, USA.,Inova Translational Medicine Institute, Falls Church, Virginia, USA
| | - William A Gahl
- NIH Undiagnosed Diseases Program, Common Fund, Office of the Director, NIH, Maryland, USA.,Medical Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, Maryland, USA.,Office of the Clinical Director, National Human Genome Research Institute, NIH, Bethesda, Maryland, USA
| | - Meral Gunay-Aygun
- Medical Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, Maryland, USA.,Office of the Clinical Director, National Human Genome Research Institute, NIH, Bethesda, Maryland, USA.,Department of Pediatrics and McKusick-Nathans Institute of Genetic Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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9
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Yuan G, Singh G, Chen S, Perez KC, Wu Y, Liu B, Helms JA. Cleft Palate and Aglossia Result From Perturbations in Wnt and Hedgehog Signaling. Cleft Palate Craniofac J 2016; 54:269-280. [PMID: 27259005 DOI: 10.1597/15-178] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
OBJECTIVE The objective of this study was to explore the molecular basis for cleft secondary palate and arrested tongue development caused by the loss of the intraflagellar transport protein, Kif3a. DESIGN Kif3a mutant embryos and their littermate controls were analyzed for defects in facial development at multiple stages of embryonic development. Histology was employed to understand the effects of Kif3a deletion on palate and tongue development. Various transgenic reporter strains were used to understand how deletion of Kif3a affected Hedgehog and Wnt signaling. Immunostaining for structural elements of the tongue and for components of the Wnt pathway were performed. BrdU activity analyses were carried out to examine how the loss of Kif3a affected cell proliferation and led to palate and tongue malformations. RESULTS Kif3a deletion causes cranial neural crest cells to become unresponsive to Hedgehog signals and hyper-responsive to Wnt signals. This aberrant molecular signaling causes abnormally high cell proliferation, but paradoxically outgrowths of the tongue and the palatal processes are reduced. The basis for this enigmatic effect can be traced back to a disruption in epithelial/mesenchymal signaling that governs facial development. CONCLUSION The primary cilium is a cell surface organelle that integrates Hh and Wnt signaling, and disruptions in the function of the primary cilium cause one of the most common-of the rarest-craniofacial birth defects observed in humans. The shared molecular basis for these dysmorphologies is an abnormally high Wnt signal simultaneous with an abnormally low Hedgehog signal. These pathways are integrated in the primary cilium.
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10
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Ibisler A, Hehr U, Barth A, Koch M, Epplen JT, Hoffjan S. Novel KIF7 Mutation in a Tunisian Boy with Acrocallosal Syndrome: Case Report and Review of the Literature. Mol Syndromol 2015; 6:173-80. [PMID: 26648833 DOI: 10.1159/000439414] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/23/2015] [Indexed: 12/14/2022] Open
Abstract
Acrocallosal syndrome (ACLS) is a rare autosomal recessive disorder characterized by agenesis of the corpus callosum, facial dysmorphism, postaxial polydactyly of the hands as well as preaxial polydactyly of the feet, and developmental delay. Mutations in the KIF7 gene, encoding a molecule within the Sonic hedgehog (SHH) pathway, have been identified as causative for ACLS but also for the fatal hydrolethalus syndrome and some cases of Joubert syndrome. We report here on a Tunisian boy who shows the clinical characteristics of ACLS and was found to have a novel homozygous KIF7 nonsense mutation. Further, we summarize the current knowledge about the clinical spectrum associated with KIF7 mutations as well as genetic and/or phenotypic overlap with ciliopathies and other mutations in the SHH pathway.
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Affiliation(s)
- Aysegül Ibisler
- Department of Human Genetics, Ruhr University, Bochum, Germany
| | - Ute Hehr
- Center for and Department of Human Genetics, University of Regensburg, Regensburg, Germany
| | - Andre Barth
- Children's Hospital Datteln, University Witten/Herdecke, Datteln, Germany
| | - Margarete Koch
- Children's Hospital Datteln, University Witten/Herdecke, Datteln, Germany
| | - Jörg T Epplen
- Department of Human Genetics, Ruhr University, Bochum, Germany
| | - Sabine Hoffjan
- Department of Human Genetics, Ruhr University, Bochum, Germany
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11
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Novas R, Cardenas-Rodriguez M, Irigoín F, Badano JL. Bardet-Biedl syndrome: Is it only cilia dysfunction? FEBS Lett 2015; 589:3479-91. [PMID: 26231314 DOI: 10.1016/j.febslet.2015.07.031] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 07/14/2015] [Accepted: 07/15/2015] [Indexed: 01/12/2023]
Abstract
Bardet-Biedl syndrome (BBS) is a genetically heterogeneous, pleiotropic disorder, characterized by both congenital and late onset defects. From the analysis of the mutational burden in patients to the functional characterization of the BBS proteins, this syndrome has become a model for both understanding oligogenic patterns of inheritance and the biology of a particular cellular organelle: the primary cilium. Here we briefly review the genetics of BBS to then focus on the function of the BBS proteins, not only in the context of the cilium but also highlighting potential extra-ciliary roles that could be relevant to the etiology of the disorder. Finally, we provide an overview of how the study of this rare syndrome has contributed to the understanding of cilia biology and how this knowledge has informed on the cellular basis of different clinical manifestations that characterize BBS and the ciliopathies.
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Affiliation(s)
- Rossina Novas
- Human Molecular Genetics Laboratory, Institut Pasteur de Montevideo, Mataojo 2020, Montevideo CP11400, Uruguay
| | | | - Florencia Irigoín
- Human Molecular Genetics Laboratory, Institut Pasteur de Montevideo, Mataojo 2020, Montevideo CP11400, Uruguay; Departamento de Histología y Embriología, Facultad de Medicina, Universidad de la República, Montevideo, Gral. Flores 2125, Montevideo CP11800, Uruguay
| | - Jose L Badano
- Human Molecular Genetics Laboratory, Institut Pasteur de Montevideo, Mataojo 2020, Montevideo CP11400, Uruguay.
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Tunovic S, Barañano KW, Barkovich JA, Strober JB, Jamal L, Slavotinek AM. Novel KIF7 missense substitutions in two patients presenting with multiple malformations and features of acrocallosal syndrome. Am J Med Genet A 2015; 167A:2767-76. [PMID: 26174511 DOI: 10.1002/ajmg.a.37249] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Accepted: 06/28/2015] [Indexed: 12/22/2022]
Abstract
We present two children who both had two missense mutations in the Kinesin Family Member 7 (KIF7) gene. A seven year old female with severe developmental delays, failure to thrive and growth retardation, infantile spasms, a cardiac vascular ring and right-sided aortic arch, imperforate anus, hydronephrosis with a right renal cyst, syndactyly and abnormal white matter was a compound heterozygote for c.3365C > G, predicting p.(Ser1122Trp) that was maternally inherited and c.2482G > A, predicting p.(Val828Met) that was paternally inherited. An eight year old female with severe developmental delays, epilepsy, left postaxial polydactyly of the hand and abnormalities of brain development including hydrocephalus, pachygyria and absence of the body and splenium of the corpus callous was a compound heterozygote for c.461G > A, predicting p.(Arg154Gln) and c.2959 G > A, predicting p.(Glu987Lys) that was maternally inherited and her father was unavailable for testing. The presentations in these children include features of acrocallosal syndrome, such as hypoplasia of the corpus callosum, enlarged ventricles, facial dysmorphism with a prominent forehead and broad halluces in the first child, but included atypical findings for individuals previously reported to have truncating mutations in KIF7, including imperforate anus, infantile spasms and severe growth retardation. We conclude that these phenotypes may result from the KIF7 sequence variants and abnormal hedgehog signaling, but that the full spectrum of KIF7-associated features remains to be determined.
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Affiliation(s)
- Sanjin Tunovic
- Division of Genetics, Department of Pediatrics, University of California, San Francisco, California
| | - Kristin W Barañano
- Department of Pediatric Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - James A Barkovich
- Department of Radiology and Biomolecular Imaging, University of California, San Francisco, California
| | - Jonathan B Strober
- Department of Pediatric Neurology, University of California, San Francisco, California
| | - Leila Jamal
- Department of Health Policy and Management, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Anne M Slavotinek
- Division of Genetics, Department of Pediatrics, University of California, San Francisco, California
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13
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Jafri M, Wake NC, Ascher DB, Pires DE, Gentle D, Morris MR, Rattenberry E, Simpson MA, Trembath RC, Weber A, Woodward ER, Donaldson A, Blundell TL, Latif F, Maher ER. Germline Mutations in the CDKN2B Tumor Suppressor Gene Predispose to Renal Cell Carcinoma. Cancer Discov 2015; 5:723-9. [DOI: 10.1158/2159-8290.cd-14-1096] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 04/09/2015] [Indexed: 11/16/2022]
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14
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Maga AM, Navarro N, Cunningham ML, Cox TC. Quantitative trait loci affecting the 3D skull shape and size in mouse and prioritization of candidate genes in-silico. Front Physiol 2015; 6:92. [PMID: 25859222 PMCID: PMC4374467 DOI: 10.3389/fphys.2015.00092] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 03/05/2015] [Indexed: 11/17/2022] Open
Abstract
We describe the first application of high-resolution 3D micro-computed tomography, together with 3D landmarks and geometric morphometrics, to map QTL responsible for variation in skull shape and size using a backcross between C57BL/6J and A/J inbred strains. Using 433 animals, 53 3D landmarks, and 882 SNPs from autosomes, we identified seven QTL responsible for the skull size (SCS.qtl) and 30 QTL responsible for the skull shape (SSH.qtl). Size, sex, and direction-of-cross were all significant factors and included in the analysis as covariates. All autosomes harbored at least one SSH.qtl, sometimes up to three. Effect sizes of SSH.qtl appeared to be small, rarely exceeding 1% of the overall shape variation. However, they account for significant amount of variation in some specific directions of the shape space. Many QTL have stronger effect on the neurocranium than expected from a random vector that will parcellate uniformly across the four cranial regions. On the contrary, most of QTL have an effect on the palate weaker than expected. Combined interval length of 30 SSH.qtl was about 315 MB and contained 2476 known protein coding genes. We used a bioinformatics approach to filter these candidate genes and identified 16 high-priority candidates that are likely to play a role in the craniofacial development and disorders. Thus, coupling the QTL mapping approach in model organisms with candidate gene enrichment approaches appears to be a feasible way to identify high-priority candidates genes related to the structure or tissue of interest.
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Affiliation(s)
- A Murat Maga
- Division of Craniofacial Medicine, Department of Pediatrics, University of Washington Seattle, WA, USA ; Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute Seattle, WA, USA
| | - Nicolas Navarro
- Laboratoire PALEVO, Ecole Pratique des Hautes Etudes Dijon, France ; UMR uB/CNRS 6282 - Biogéosciences, Université de Bourgogne Dijon, France
| | - Michael L Cunningham
- Division of Craniofacial Medicine, Department of Pediatrics, University of Washington Seattle, WA, USA ; Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute Seattle, WA, USA
| | - Timothy C Cox
- Division of Craniofacial Medicine, Department of Pediatrics, University of Washington Seattle, WA, USA ; Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute Seattle, WA, USA ; Department of Anatomy and Developmental Biology, Monash University Clayton, VIC, Australia
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15
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Rao Damerla R, Gabriel GC, Li Y, Klena NT, Liu X, Chen Y, Cui C, Pazour GJ, Lo CW. Role of cilia in structural birth defects: insights from ciliopathy mutant mouse models. ACTA ACUST UNITED AC 2015; 102:115-25. [PMID: 24975753 DOI: 10.1002/bdrc.21067] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 06/11/2014] [Indexed: 11/06/2022]
Abstract
Structural birth defect (SBD) is a major cause of morbidity and mortality in the newborn period. Although the etiology of SBD is diverse, a wide spectrum of SBD associated with ciliopathies points to the cilium as having a central role in the pathogenesis of SBDs. Ciliopathies are human diseases arising from disruption of cilia structure and/or function. They are associated with developmental anomalies in one or more organ systems and can involve defects in motile cilia, such as those in the airway epithelia or from defects in nonmotile (primary cilia) that have sensory and cell signaling function. Availability of low cost next generation sequencing has allowed for explosion of new knowledge in genetic etiology of ciliopathies. This has led to the appreciation that many genes are shared in common between otherwise clinically distinct ciliopathies. Further insights into the relevance of the cilium in SBD has come from recovery of pathogenic mutations in cilia-related genes from many large-scale mouse forward genetic screens with differing developmental phenotyping focus. Our mouse mutagenesis screen for congenital heart disease (CHD) using noninvasive fetal echocardiography has yielded a marked enrichment for pathogenic mutations in genes required for motile or primary cilia function. These novel mutant mouse models will be invaluable for modeling human ciliopathies and further interrogating the role of the cilium in the pathogenesis of SBD and CHD. Overall, these findings suggest a central role for the cilium in the pathogenesis of a wide spectrum of developmental anomalies associated with CHD and SBDs.
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Affiliation(s)
- Rama Rao Damerla
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
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16
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Jia Y, Wang Y, Xie J. The Hedgehog pathway: role in cell differentiation, polarity and proliferation. Arch Toxicol 2015; 89:179-91. [PMID: 25559776 PMCID: PMC4630008 DOI: 10.1007/s00204-014-1433-1] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 12/04/2014] [Indexed: 02/07/2023]
Abstract
Hedgehog (Hh) is first described as a genetic mutation that has "spiked" phenotype in the cuticles of Drosophila in later 1970s. Since then, Hh signaling has been implicated in regulation of differentiation, proliferation, tissue polarity, stem cell population and carcinogenesis. The first link of Hh signaling to cancer was established through discovery of genetic mutations of Hh receptor gene PTCH1 being responsible for Gorlin syndrome in 1996. It was later shown that Hh signaling is associated with many types of cancer, including skin, leukemia, lung, brain and gastrointestinal cancers. Another important milestone for the Hh research field is the FDA approval for the clinical use of Hh inhibitor Erivedge/Vismodegib for treatment of locally advanced and metastatic basal cell carcinomas. However, recent clinical trials of Hh signaling inhibitors in pancreatic, colon and ovarian cancer all failed, indicating a real need for further understanding of Hh signaling in cancer. In this review, we will summarize recent progress in the Hh signaling mechanism and its role in human cancer.
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Affiliation(s)
- Yanfei Jia
- Central Laboratory, Jinan Central Hospital Affiliated to Shandong, University, Jinan, China
- Division of Hematology and Oncology, Department of Pediatrics, Wells Center for Pediatric Research, Indiana University Simon Cancer Center, Indiana University, Indianapolis, IN 46202, USA
| | - Yunshan Wang
- Central Laboratory, Jinan Central Hospital Affiliated to Shandong, University, Jinan, China
| | - Jingwu Xie
- Division of Hematology and Oncology, Department of Pediatrics, Wells Center for Pediatric Research, Indiana University Simon Cancer Center, Indiana University, Indianapolis, IN 46202, USA
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Investigation of genetic factors underlying typical orofacial clefts: mutational screening and copy number variation. J Hum Genet 2014; 60:17-25. [PMID: 25391604 DOI: 10.1038/jhg.2014.96] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 10/01/2014] [Accepted: 10/10/2014] [Indexed: 12/13/2022]
Abstract
Typical orofacial clefts (OFCs) comprise cleft lip, cleft palate and cleft lip and palate. The complex etiology has been postulated to involve chromosome rearrangements, gene mutations and environmental factors. A group of genes including IRF6, FOXE1, GLI2, MSX2, SKI, SATB2, MSX1 and FGF has been implicated in the etiology of OFCs. Recently, the role of the copy number variations (CNVs) has been studied in genetic defects and diseases. CNVs act by modifying gene expression, disrupting gene sequence or altering gene dosage. The aims of this study were to screen the above-mentioned genes and to investigate CNVs in patients with OFCs. The sample was composed of 23 unrelated individuals who were grouped according to phenotype (associated with other anomalies or isolated) and familial recurrence. New sequence variants in GLI2, MSX1 and FGF8 were detected in patients, but not in their parents, as well as in 200 control chromosomes, indicating that these were rare variants. CNV screening identified new genes that can influence OFC pathogenesis, particularly highlighting TCEB3 and KIF7, that could be further analyzed. The findings of the present study suggest that the mechanism underlying CNV associated with sequence variants may play a role in the etiology of OFC.
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Clark GR, Sciacovelli M, Gaude E, Walsh DM, Kirby G, Simpson MA, Trembath RC, Berg JN, Woodward ER, Kinning E, Morrison PJ, Frezza C, Maher ER. Germline FH mutations presenting with pheochromocytoma. J Clin Endocrinol Metab 2014; 99:E2046-50. [PMID: 25004247 DOI: 10.1210/jc.2014-1659] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
CONTEXT At least a third of the patients with pheochromocytoma (PCC) or paraganglioma (PGL) harbor an underlying germline mutation in a known PCC/PGL gene. Mutations in genes (SDHB, SDHD, SDHC, and SDHA) encoding a component of the tricarboxylic acid cycle, succinate dehydrogenase (SDH), are a major cause of inherited PCC and PGL. SDHB mutations are also, albeit less frequently, associated with inherited renal cell carcinoma. Inactivation of SDH and another tricarboxylic acid cycle component, fumarate hydratase (FH), have both been associated with abnormalities of cellular metabolism, responsible for the activation of hypoxic gene response pathways and epigenetic alterations (eg, DNA methylation). However, the clinical phenotype of germline mutations in SDHx genes and FH is usually distinct, with FH mutations classically associated with hereditary cutaneous and uterine leiomyomatosis and renal cell carcinoma, although recently an association with PCC/PGL has been reported. OBJECTIVE AND DESIGN To identify potential novel PCC/PGL predisposition genes, we initially undertook exome resequencing studies in a case of childhood PCC, and subsequently FH mutation analysis in a further 71 patients with PCC, PGL, or head and neck PGL. RESULTS After identifying a candidate FH missense mutation in the exome study, we then detected a further candidate missense mutation (p.Glu53Lys) by candidate gene sequencing. In vitro analyses demonstrated that both missense mutations (p.Cys434Tyr and p.Glu53Lys) were catalytically inactive. CONCLUSIONS These findings 1) confirm that germline FH mutations may present, albeit rarely with PCC or PGL; and 2) extend the clinical phenotype associated with FH mutations to pediatric PCC.
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Affiliation(s)
- Graeme R Clark
- Department of Medical Genetics (G.R.C., E.R.M.), University of Cambridge and National Institute for Health Research, Cambridge Biomedical Research Centre, Cambridge CB2 0QQ, United Kingdom; Medical Research Council (MRC) Cancer Unit (M.S., E.G., C.F.), University of Cambridge, Hutchison/MRC Research Centre, Cambridge CB2 0XZ, United Kingdom; Centre for Rare Diseases and Personalized Medicine (D.M.W., G.K., E.R.W.), University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom; West Midlands Regional Genetics Service (G.K., E.R.W.), Birmingham Women's Hospital, Birmingham B15 2TG, United Kingdom; Division of Genetics and Molecular Medicine (M.A.S., R.C.T.), King's College London School of Medicine, Guy's Hospital, London WC2R 2LS, United Kingdom; Department of Clinical Genetics (J.N.B.), University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, United Kingdom; Department of Clinical Genetics (E.K.), Royal Hospital for Sick Children (Yorkhill), Glasgow G3 8SJ, United Kingdom; and Department of Medical Genetics (P.J.M.), Queen's University Belfast, Belfast Health and Social Care Trust, Belfast BT9 7AB, United Kingdom
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Cooper DN, Krawczak M, Polychronakos C, Tyler-Smith C, Kehrer-Sawatzki H. Where genotype is not predictive of phenotype: towards an understanding of the molecular basis of reduced penetrance in human inherited disease. Hum Genet 2013; 132:1077-130. [PMID: 23820649 PMCID: PMC3778950 DOI: 10.1007/s00439-013-1331-2] [Citation(s) in RCA: 417] [Impact Index Per Article: 37.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 06/15/2013] [Indexed: 02/06/2023]
Abstract
Some individuals with a particular disease-causing mutation or genotype fail to express most if not all features of the disease in question, a phenomenon that is known as 'reduced (or incomplete) penetrance'. Reduced penetrance is not uncommon; indeed, there are many known examples of 'disease-causing mutations' that fail to cause disease in at least a proportion of the individuals who carry them. Reduced penetrance may therefore explain not only why genetic diseases are occasionally transmitted through unaffected parents, but also why healthy individuals can harbour quite large numbers of potentially disadvantageous variants in their genomes without suffering any obvious ill effects. Reduced penetrance can be a function of the specific mutation(s) involved or of allele dosage. It may also result from differential allelic expression, copy number variation or the modulating influence of additional genetic variants in cis or in trans. The penetrance of some pathogenic genotypes is known to be age- and/or sex-dependent. Variable penetrance may also reflect the action of unlinked modifier genes, epigenetic changes or environmental factors. At least in some cases, complete penetrance appears to require the presence of one or more genetic variants at other loci. In this review, we summarize the evidence for reduced penetrance being a widespread phenomenon in human genetics and explore some of the molecular mechanisms that may help to explain this enigmatic characteristic of human inherited disease.
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Affiliation(s)
- David N. Cooper
- Institute of Medical Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XN UK
| | - Michael Krawczak
- Institute of Medical Informatics and Statistics, Christian-Albrechts University, 24105 Kiel, Germany
| | | | - Chris Tyler-Smith
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA UK
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