1
|
Yao Y, Gu X, Xu X, Ge S, Jia R. Novel insights into RB1 mutation. Cancer Lett 2022; 547:215870. [PMID: 35964818 DOI: 10.1016/j.canlet.2022.215870] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 08/05/2022] [Accepted: 08/05/2022] [Indexed: 01/09/2023]
Abstract
Since the discovery of the retinoblastoma susceptibility gene (RB1) decades ago, RB1 has been regarded as a prototype tumor suppressor gene providing a paradigm for tumor genetic research. Constant research has updated the understanding of RB1-related pathways and their impact on tumor and nontumor diseases. Mutation of RB1 gene has been observed in multiple types of malignant tumors including prostate cancer, lung cancer, breast cancer, and almost every familial and sporadic case of retinoblastoma. Even if well-known and long-investigated, the application potential of RB1 mutation has not been fully tapped. In this review, we focus on the mechanism underlying RB1 mutation during oncogenesis. Therapeutically, we have further discussed potential clinical strategies by targeting RB1-mutated cancers. The unsolved problems and prospects of RB1 mutation are also discussed.
Collapse
Affiliation(s)
- Yiran Yao
- Department of Ophthalmology, Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Shanghai, China.
| | - Xiang Gu
- Department of Ophthalmology, Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Shanghai, China.
| | - Xiaofang Xu
- Department of Ophthalmology, Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Shanghai, China.
| | - Shengfang Ge
- Department of Ophthalmology, Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Shanghai, China.
| | - Renbing Jia
- Department of Ophthalmology, Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Orbital Diseases and Ocular Oncology, Shanghai, China.
| |
Collapse
|
2
|
Lan X, Xu W, Tang X, Ye H, Song X, Lin L, Ren X, Yu G, Zhang H, Wu S. Spectrum of RB1 Germline Mutations and Clinical Features in Unrelated Chinese Patients With Retinoblastoma. Front Genet 2020; 11:142. [PMID: 32218800 PMCID: PMC7080181 DOI: 10.3389/fgene.2020.00142] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 02/06/2020] [Indexed: 11/13/2022] Open
Abstract
Retinoblastoma (Rb) is a primary intraocular malignant tumor that occurs primarily in children, and results from loss-of-function mutations in the RB transcriptional corepressor 1 (RB1) gene. Genetic testing forms the basis of genetic counseling for affected families, as well as for clinical management of this disease. The aim of this study was to identify germline RB1 mutations and correlate the identified mutations with the clinical features of Rb patients. Genomic DNA was isolated from peripheral blood of 180 unrelated Rb patients and their parents (118 unilaterally and 62 bilaterally affected probands). Mutations in the RB1 gene, including the promoter region and exons 1-27 with flanking intronic sequences, were identified by Sanger sequencing. The samples with negative sequencing results were further subjected to methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) to detect gross deletions or duplications. Sixty-three distinct mutations were identified in 75 of the 180 (41.7%) probands. Of the 75 patients carrying RB1 mutations, 56 developed bilateral Rb, while 19 developed unilateral Rb. The total detection rates for bilateral and unilateral Rb were 90.3% (56/62) and 16.1% (19/118), respectively. Among the 75 patients, the spectrum of mutation types comprised 29.3% (22/75) nonsense mutations, 22.7% (17/75) splicing mutations, 17.3% (13/75) small insertions/deletions, 16.0% (12/75) large deletions/duplications, and 13.3% (10/75) missense mutations, while only 1% (1/75) of the mutations were in the promoter region of the RB1 gene. Age at diagnosis was significantly different (p < 0.01) between patients with positive and negative test results for germline RB1 mutations. A c.2359C > T mutation (p.R787X) was identified in identical twins, but one child was affected bilaterally and the other unilaterally. Of the five patients with deletion of the entire RB1 gene, the deletion of two patients was inherited from unaffected parents. In conclusion, in this study, we provide a comprehensive spectrum of RB1 germline mutations in Chinese Rb patients, and describe the correlations among RB1 mutations, age at diagnosis, and laterality; moreover, we report that the clinical features of individuals carrying an identical mutation in the RB1 gene were highly variable, indicating that the pathogenesis of Rb is more complicated than currently believed.
Collapse
Affiliation(s)
- Xiaoping Lan
- Molecular Diagnostic Laboratory, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Wuhen Xu
- Molecular Diagnostic Laboratory, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Xiaojun Tang
- Molecular Diagnostic Laboratory, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Haiyun Ye
- Department of Ophthalmology, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Xiaozhen Song
- Molecular Diagnostic Laboratory, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Longlong Lin
- Department of Neurology, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Xiang Ren
- Department of Radiology, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Guangjun Yu
- Molecular Diagnostic Laboratory, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Hong Zhang
- Department of Clinical Laboratory, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Shengnan Wu
- Molecular Diagnostic Laboratory, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
| |
Collapse
|
3
|
Imperatore V, Pinto AM, Gelli E, Trevisson E, Morbidoni V, Frullanti E, Hadjistilianou T, De Francesco S, Toti P, Gusson E, Roversi G, Accogli A, Capra V, Mencarelli MA, Renieri A, Ariani F. Parent-of-origin effect of hypomorphic pathogenic variants and somatic mosaicism impact on phenotypic expression of retinoblastoma. Eur J Hum Genet 2018; 26:1026-1037. [PMID: 29662154 DOI: 10.1038/s41431-017-0054-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 10/27/2017] [Accepted: 11/23/2017] [Indexed: 11/09/2022] Open
Abstract
Retinoblastoma is the most common eye cancer in children. Numerous families have been described displaying reduced penetrance and expressivity. An extensive molecular characterization of seven families led us to characterize the two main mechanisms impacting on phenotypic expression, as follows: (i) mosaicism of amorphic pathogenic variants; and (ii) parent-of-origin-effect of hypomorphic pathogenic variants. Somatic mosaicism for RB1 splicing variants (c.1960+5G>C and c.2106+2T>C), leading to a complete loss of function was demonstrated by high-depth NGS in two families. In both cases, the healthy carrier parent (one with retinoma) showed a variant frequency lower than that expected for a heterozygous individual, indicating a 56-60% mosaicism level. Previous evidences of a ~3-fold excess of RB1 maternal canonical transcript led us to hypothesize that this differential allelic expression could influence phenotypic outcome in families at risk for RB onset. Accordingly, in five families, we identified a higher tumor risk associated with paternally inherited hypomorphic pathogenic variants, namely a deletion resulting in the loss of 37 amino acids at the N-terminus (c.608-16_608del), an exonic substitution with a "leaky" splicing effect (c.1331A>G), a partially deleterious substitution (c.1981C>T) and a truncating C-terminal variant (c.2663+2T>C). The identification of these mechanisms changes the genetic/prenatal counseling and the clinical management of families, indicating a higher recurrence risk when the hypomorphic pathogenic variant is inherited from the father, and suggesting the need for second tumor surveillance in unaffected carriers at risk of developing adult-onset cancer such as osteosarcoma or leiomyosarcoma.
Collapse
Affiliation(s)
| | - Anna Maria Pinto
- Medical Genetics, University of Siena, Siena, Italy.,Genetica Medica, Azienda Ospedaliera Universitaria Senese, Siena, Italy
| | - Elisa Gelli
- Medical Genetics, University of Siena, Siena, Italy
| | - Eva Trevisson
- Department of Woman and Child Health, University of Padova Istituto di Ricerca Pediatrica, IRP, Città della Speranza, Padova, Italy.,Istituto di Ricerca Pediatrica, IRP, Città della Speranza, Padova, Italy
| | - Valeria Morbidoni
- Department of Woman and Child Health, University of Padova Istituto di Ricerca Pediatrica, IRP, Città della Speranza, Padova, Italy.,Istituto di Ricerca Pediatrica, IRP, Città della Speranza, Padova, Italy
| | | | - Theodora Hadjistilianou
- Unit of Ophthalmology and Retinoblastoma Referral Center, Department of Surgery, University of Siena, Policlinico 'Santa Maria alle Scotte', Siena, Italy
| | - Sonia De Francesco
- Unit of Ophthalmology and Retinoblastoma Referral Center, Department of Surgery, University of Siena, Policlinico 'Santa Maria alle Scotte', Siena, Italy
| | - Paolo Toti
- Department of Medical Biotechnology, Section of Pathology, University of Siena, Policlinico 'Santa Maria alle Scotte', Siena, Italy
| | - Elena Gusson
- Unit of Ophthalmology, Azienda Ospedaliera Universitaria Integrata, Verona, Italy
| | - Gaia Roversi
- Department of Medicine and Surgery, University Milan-Bicocca; Ospedale San Gerardo, ASST Monza, Monza, Italy
| | | | | | - Maria Antonietta Mencarelli
- Medical Genetics, University of Siena, Siena, Italy.,Genetica Medica, Azienda Ospedaliera Universitaria Senese, Siena, Italy
| | - Alessandra Renieri
- Medical Genetics, University of Siena, Siena, Italy. .,Genetica Medica, Azienda Ospedaliera Universitaria Senese, Siena, Italy.
| | - Francesca Ariani
- Medical Genetics, University of Siena, Siena, Italy.,Genetica Medica, Azienda Ospedaliera Universitaria Senese, Siena, Italy
| |
Collapse
|
4
|
Parma D, Ferrer M, Luce L, Giliberto F, Szijan I. RB1 gene mutations in Argentine retinoblastoma patients. Implications for genetic counseling. PLoS One 2017; 12:e0189736. [PMID: 29261756 PMCID: PMC5738096 DOI: 10.1371/journal.pone.0189736] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 11/30/2017] [Indexed: 11/21/2022] Open
Abstract
Retinoblastoma (RB) is an inherited childhood ocular cancer caused by mutations in the tumor suppressor RB1 gene. Identification of RB1 mutations is essential to assess the risk of developing retinoblastoma in the patients´ relatives. Retinoblastoma is a potentially curable cancer and an early diagnosis is critical for survival and eye preservation. Unilateral retinoblastoma is mostly non-heritable and results from two somatic mutations whereas bilateral retinoblastoma is heritable and results from one germline and one somatic mutation, both have high penetrance, 90%. The purpose of this study was to identify causative RB1 mutations in RB patients with different clinical presentations. A comprehensive approach was used to study a cohort of 34 patients with unilateral, bilateral and trilateral retinoblastoma. Blood and tumor DNA was analyzed by sequencing and multiplex ligation-dependent probe amplification (MLPA) assay. Validation of an insertion mutation was performed by cloning the PCR product. Most of the patients in our cohort had unilateral RB, eight patients had bilateral RB and one patient had a trilateral tumor with ocular and suprasellar/sellar locations. Other tumors in addition to retinoblastoma were also found in the affected families. One patient had two syndromes, retinoblastoma and schwannomatosis, and another RB patient had a father with a retinoma. Five out of the 25 unilateral RB patients carried germinal mutations (20%), which were mostly missense mutations. The bilateral and trilateral patients carried splice-site, nonsense and frameshift mutations as well as a whole RB1 gene deletion. Missense mutations were associated with mild phenotype: unilateral retinoblastoma, retinoma or no tumor. In this study we identified causative RB1 mutations in most bilateral RB patients and in some unilateral RB patients, including five novel mutations. These data are crucial for genetic counseling and confirm the need to perform complete genetic screening for RB1 mutations in both constitutional and tumor tissues.
Collapse
Affiliation(s)
- Diana Parma
- Cátedra de Genética, Facultad de Farmacia y Bioquimica, Universidad de Buenos Aires. Buenos Aires. Argentina
| | - Marcela Ferrer
- Division de Neurocirugia, Hospital de Clinicas “Jose de San Martin”, Universidad de Buenos Aires. Buenos Aires. Argentina
| | - Leonela Luce
- Cátedra de Genética, Facultad de Farmacia y Bioquimica, Universidad de Buenos Aires. Buenos Aires. Argentina
| | - Florencia Giliberto
- Cátedra de Genética, Facultad de Farmacia y Bioquimica, Universidad de Buenos Aires. Buenos Aires. Argentina
| | - Irene Szijan
- Cátedra de Genética, Facultad de Farmacia y Bioquimica, Universidad de Buenos Aires. Buenos Aires. Argentina
- * E-mail:
| |
Collapse
|
5
|
APC/C and retinoblastoma interaction: cross-talk of retinoblastoma protein with the ubiquitin proteasome pathway. Biosci Rep 2016; 36:BSR20160152. [PMID: 27402801 PMCID: PMC5025812 DOI: 10.1042/bsr20160152] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 07/08/2016] [Indexed: 12/15/2022] Open
Abstract
The ubiquitin (Ub) ligase anaphase promoting complex/cyclosome (APC/C) and the tumour suppressor retinoblastoma protein (pRB) play key roles in cell cycle regulation. APC/C is a critical regulator of mitosis and G1-phase of the cell cycle whereas pRB keeps a check on proliferation by inhibiting transition to the S-phase. APC/C and pRB interact with each other via the co-activator of APC/C, FZR1, providing an alternative pathway of regulation of G1 to S transition by pRB using a post-translational mechanism. Both pRB and FZR1 have complex roles and are implicated not only in regulation of cell proliferation but also in differentiation, quiescence, apoptosis, maintenance of chromosomal integrity and metabolism. Both are also targeted by transforming viruses. We discuss recent advances in our understanding of the involvement of APC/C and pRB in cell cycle based decisions and how these insights will be useful for development of anti-cancer and anti-viral drugs.
Collapse
|
6
|
Eloy P, Dehainault C, Sefta M, Aerts I, Doz F, Cassoux N, Lumbroso le Rouic L, Stoppa-Lyonnet D, Radvanyi F, Millot GA, Gauthier-Villars M, Houdayer C. A Parent-of-Origin Effect Impacts the Phenotype in Low Penetrance Retinoblastoma Families Segregating the c.1981C>T/p.Arg661Trp Mutation of RB1. PLoS Genet 2016; 12:e1005888. [PMID: 26925970 PMCID: PMC4771840 DOI: 10.1371/journal.pgen.1005888] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 01/30/2016] [Indexed: 01/12/2023] Open
Abstract
Retinoblastoma (Rb), the most common pediatric intraocular neoplasm, results from inactivation of both alleles of the RB1 tumor suppressor gene. The second allele is most commonly lost, as demonstrated by loss of heterozygosity studies. RB1 germline carriers usually develop bilateral tumors, but some Rb families display low penetrance and variable expressivity. In order to decipher the underlying mechanisms, 23 unrelated low penetrance pedigrees segregating the common c.1981C>T/p.Arg661Trp mutation and other low penetrance mutations were studied. In families segregating the c.1981C>T mutation, we demonstrated, for the first time, a correlation between the gender of the transmitting carrier and penetrance, as evidenced by Fisher's exact test: the probability of being unaffected is 90.3% and 32.5% when the mutation is inherited from the mother and the father, respectively (p-value = 7.10(-7). Interestingly, a similar correlation was observed in families segregating other low penetrance alleles. Consequently, we investigated the putative involvement of an imprinted, modifier gene in low penetrance Rb. We first ruled out a MED4-driven mechanism by MED4 methylation and expression analyses. We then focused on the differentially methylated CpG85 island located in intron 2 of RB1 and showing parent-of-origin-specific DNA methylation. This differential methylation promotes expression of the maternal c.1981C>T allele. We propose that the maternally inherited c.1981C>T/p.Arg661Trp allele retains sufficient tumor suppressor activity to prevent retinoblastoma development. In contrast, when the mutation is paternally transmitted, the low residual activity would mimic a null mutation and subsequently lead to retinoblastoma. This implies that the c.1981C>T mutation is not deleterious per se but needs to be destabilized in order to reach pRb haploinsufficiency and initiate tumorigenesis. We suggest that this phenomenon might be a general mechanism to explain phenotypic differences in low penetrance Rb families.
Collapse
Affiliation(s)
| | | | - Meriem Sefta
- CNRS UMR144, centre de recherche de l'Institut Curie, Paris, France
| | - Isabelle Aerts
- Département d'oncologie pédiatrique, adolescents jeunes adultes, Institut Curie, Paris, France
| | - François Doz
- Département d'oncologie pédiatrique, adolescents jeunes adultes, Institut Curie, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Nathalie Cassoux
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
- Département d’oncologie chirurgicale, service d’Ophtalmologie, Institut Curie, Paris, France
| | - Livia Lumbroso le Rouic
- Département d’oncologie chirurgicale, service d’Ophtalmologie, Institut Curie, Paris, France
| | - Dominique Stoppa-Lyonnet
- Service de Génétique, Institut Curie, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
- INSERM U830, centre de recherche de l'Institut Curie, Paris, France
| | | | - Gaël A. Millot
- Institut Curie, PSL Research University, Paris, France
- CNRS UMR 3244, Paris, France
- Sorbonne Universités, UPMC Univ Paris 06, Paris, France
| | | | - Claude Houdayer
- Service de Génétique, Institut Curie, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
- INSERM U830, centre de recherche de l'Institut Curie, Paris, France
- * E-mail:
| |
Collapse
|
7
|
Yang QE, Nagaoka SI, Gwost I, Hunt PA, Oatley JM. Inactivation of Retinoblastoma Protein (Rb1) in the Oocyte: Evidence That Dysregulated Follicle Growth Drives Ovarian Teratoma Formation in Mice. PLoS Genet 2015; 11:e1005355. [PMID: 26176933 PMCID: PMC4503754 DOI: 10.1371/journal.pgen.1005355] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 06/12/2015] [Indexed: 02/02/2023] Open
Abstract
The origin of most ovarian tumors is undefined. Here, we report development of a novel mouse model in which conditional inactivation of the tumor suppressor gene Rb1 in oocytes leads to the formation of ovarian teratomas (OTs). While parthenogenetically activated ooctyes are a known source of OT in some mutant mouse models, enhanced parthenogenetic propensity in vitro was not observed for Rb1-deficient oocytes. Further analyses revealed that follicle recruitment and growth is disrupted in ovaries of mice with conditional inactivation of Rb1, leading to abnormal accumulation of secondary/preantral follicles. These findings underpin the concept that miscues between the germ cell and somatic compartments cause premature oocyte activation and the formation of OTs. Furthermore, these results suggest that defects in folliculogenesis and a permissive genetic background are sufficient to drive OT development, even in the absence of enhanced parthenogenetic activation. Thus, we have discovered a novel role of Rb1 in regulating the entry of primordial oocytes into the pool of growing follicles and signaling between the oocyte and granulosa cells during the protracted process of oocyte growth. Our findings, coupled with data from studies of other OT models, suggest that defects in the coordinated regulation between growth of the oocyte and somatic components in follicles are an underlying cause of OT formation.
Collapse
Affiliation(s)
- Qi-En Yang
- Center for Reproductive Biology, School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America
| | - So I. Nagaoka
- Center for Reproductive Biology, School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America
| | - Ivy Gwost
- Center for Reproductive Biology, School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America
| | - Patricia A. Hunt
- Center for Reproductive Biology, School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America
| | - Jon M. Oatley
- Center for Reproductive Biology, School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America
- * E-mail:
| |
Collapse
|
8
|
Screening of RB1 gene mutations in Chinese patients with retinoblastoma and preliminary exploration of genotype-phenotype correlations. Mol Vis 2014; 20:545-52. [PMID: 24791139 PMCID: PMC4000713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 04/23/2014] [Indexed: 11/17/2022] Open
Abstract
PURPOSE Retinoblastoma (RB) sets the paradigm for hereditary cancer syndromes, for which medical care can change depending on the results of genetic testing. In this study, we screened constitutional mutations in the RB1 gene via a method combining DNA sequencing and multiplex ligation-dependent probe amplification (MLPA), and performed a preliminary exploration of genotype-phenotype correlations. METHODS The peripheral blood of 85 retinoblastoma probands, including 39 bilateral and 46 unilateral, was collected, and genomic DNA was extracted. DNA sequencing was conducted first. MLPA analysis was applied for patients with bilateral RB with negative sequencing results and unilateral probands whose age at diagnosis was less than 1 year old. RESULTS Thirty-four distinct mutations were identified in 40 (47.1%) of the 85 probands (36 bilateral and four unilateral), of which 20% (8/40) was identified by MLPA. The total detection rate in bilateral cases was 92.3% (36/39). Of the total mutations identified, 77.5% (31/40) probands with a mean age of 10.7 months at diagnosis had null mutations, and 22.5% (9/40) with a mean age of 13.5 months at diagnosis had in-frame mutations. Of the 31 probands with null mutations, bilateral RB accounted for 96.8% (30/31). Of the nine probands with in-frame mutations, 66.7% had bilateral RB. There were seven new mutations of RB1 identified in this report, including six null mutations and one missense mutation. Clinical staging of the tumor did not show obvious differences between patients with null mutations and in-frame mutations. CONCLUSIONS Our results confirm that the type of mutation is related to age of onset and the laterality, but not staging of the retinoblastoma tumor. MLPA is a reliable method for detecting gross deletion or duplication of the RB1 gene. The combination of sequencing and MLPA improves the clinical diagnosis of RB.
Collapse
|
9
|
|
10
|
Manwar Hussain MR, Khan A, Ali Mohamoud HS. From genes to health - challenges and opportunities. Front Pediatr 2014; 2:12. [PMID: 24624370 PMCID: PMC3939617 DOI: 10.3389/fped.2014.00012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Accepted: 02/10/2014] [Indexed: 11/13/2022] Open
Abstract
In genome science, the advancement in high-throughput sequencing technologies and bioinformatics analysis is facilitating the better understanding of Mendelian and complex trait inheritance. Charting the genetic basis of complex diseases - including pediatric cancer, and interpreting huge amount of next-generation sequencing data are among the major technical challenges to be overcome in order to understand the molecular basis of various diseases and genetic disorders. In this review, we provide insights into some major challenges currently hindering a better understanding of Mendelian and complex trait inheritance, and thus impeding medical benefits to patients.
Collapse
Affiliation(s)
- Muhammad Ramzan Manwar Hussain
- Princess Al-Jawhara Al-Brahim Center of Excellence in Research of Hereditary Diseases (PACER-HD), Department of Genetic Medicine, King Abdulaziz University , Jeddah , Saudi Arabia
| | - Asifullah Khan
- Department of Biochemistry, Abdul Wali Khan University , Mardan , Pakistan
| | - Hussein Sheikh Ali Mohamoud
- Princess Al-Jawhara Al-Brahim Center of Excellence in Research of Hereditary Diseases (PACER-HD), Department of Genetic Medicine, King Abdulaziz University , Jeddah , Saudi Arabia
| |
Collapse
|
11
|
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.
Collapse
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
| | | |
Collapse
|
12
|
Abidi O, Knari S, Sefri H, Charif M, Senechal A, Hamel C, Rouba H, Zaghloul K, El Kettani A, Lenaers G, Barakat A. Mutational analysis of the RB1 gene in Moroccan patients with retinoblastoma. Mol Vis 2011; 17:3541-7. [PMID: 22219649 PMCID: PMC3250372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 12/27/2011] [Indexed: 10/31/2022] Open
Abstract
PURPOSE Retinoblastoma (RB), the most common intraocular tumor occurring in infancy and early childhood, is most often related to mutations in the RB1 gene. In this study, we screened the RB1 germline mutations in 41 unrelated Moroccan patients with retinoblastoma, 25 heritable cases, and 16 sporadic unilateral cases. METHODS After complete ophthalmic examinations were performed and consent obtained, DNA was extracted from peripheral blood, and screening of RB1 mutations was performed with PCR direct sequencing of the promoter and the 27 coding exons of the RB1 gene. RESULTS We identified ten germline mutations in 10/41 (24.39%) unrelated patients, among which three had not been previously reported. The mutation detection rate was 40% (10/25) in the heritable cases and 0% (0/16) in the sporadic unilateral cases. Of these mutations, six were nonsense, and three were frameshifts, all associated with severe phenotypes resulting in bilateral and multifocal tumors. One splice site mutation was found in a familial case associated with a low expressivity phenotype resulting in unilateral and unifocal tumors. Moreover, eight intronic variants were identified, three of which were novel. CONCLUSIONS This first report of RB1 gene screening in Moroccan patients with retinoblastoma shows a comparable mutational spectrum to those reported previously, which has evident importance for managing patients with retinoblastoma and their families.
Collapse
Affiliation(s)
- Omar Abidi
- Laboratoire de Génétique Humaine et Biologie Moléculaire, Institut Pasteur du Maroc,
Casablanca, Morocco
| | - Sara Knari
- Service d’Ophtalmologie pédiatrique, Hôpital 20 Août, CHU de Casablanca, Morocco
| | - Hajar Sefri
- Laboratoire de Génétique Humaine et Biologie Moléculaire, Institut Pasteur du Maroc,
Casablanca, Morocco
| | - Majida Charif
- Laboratoire de Génétique Humaine et Biologie Moléculaire, Institut Pasteur du Maroc,
Casablanca, Morocco
| | - Audrey Senechal
- Institut des Neurosciences de Montpellier, Génétique et thérapie des cécités rétiniennes et neuropathies optiques héréditaires, INSERM U-1051, Université de Montpellier Sud de France, Montpellier, France
| | - Christian Hamel
- Institut des Neurosciences de Montpellier, Génétique et thérapie des cécités rétiniennes et neuropathies optiques héréditaires, INSERM U-1051, Université de Montpellier Sud de France, Montpellier, France
| | - Hassan Rouba
- Laboratoire de Génétique Humaine et Biologie Moléculaire, Institut Pasteur du Maroc,
Casablanca, Morocco
| | - Khalid Zaghloul
- Service d’Ophtalmologie pédiatrique, Hôpital 20 Août, CHU de Casablanca, Morocco
| | - Asmaa El Kettani
- Service d’Ophtalmologie pédiatrique, Hôpital 20 Août, CHU de Casablanca, Morocco
| | - Guy Lenaers
- Institut des Neurosciences de Montpellier, Génétique et thérapie des cécités rétiniennes et neuropathies optiques héréditaires, INSERM U-1051, Université de Montpellier Sud de France, Montpellier, France
| | - Abdelhamid Barakat
- Laboratoire de Génétique Humaine et Biologie Moléculaire, Institut Pasteur du Maroc,
Casablanca, Morocco
| |
Collapse
|