1
|
Pan YW, Ou TY, Chou YY, Kuo PL, Hsiao HP, Chiu PC, Lin JL, Lo FS, Wang CH, Chen PC, Tsai MC. Syndromic ciliopathy: a taiwanese single-center study. BMC Med Genomics 2024; 17:106. [PMID: 38671463 PMCID: PMC11046915 DOI: 10.1186/s12920-024-01880-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 04/16/2024] [Indexed: 04/28/2024] Open
Abstract
BACKGROUND Syndromic ciliopathies are a group of congenital disorders characterized by broad clinical and genetic overlap, including obesity, visual problems, skeletal anomalies, mental retardation, and renal diseases. The hallmark of the pathophysiology among these disorders is defective ciliary functions or formation. Many different genes have been implicated in the pathogenesis of these diseases, but some patients still remain unclear about their genotypes. METHODS The aim of this study was to identify the genetic causes in patients with syndromic ciliopathy. Patients suspected of or meeting clinical diagnostic criteria for any type of syndromic ciliopathy were recruited at a single diagnostic medical center in Southern Taiwan. Whole exome sequencing (WES) was employed to identify their genotypes and elucidate the mutation spectrum in Taiwanese patients with syndromic ciliopathy. Clinical information was collected at the time of patient enrollment. RESULTS A total of 14 cases were molecularly diagnosed with syndromic ciliopathy. Among these cases, 10 had Bardet-Biedl syndrome (BBS), comprising eight BBS2 patients and two BBS7 patients. Additionally, two cases were diagnosed with Alström syndrome, one with Oral-facial-digital syndrome type 14, and another with Joubert syndrome type 10. A total of 4 novel variants were identified. A recurrent splice site mutation, BBS2: c.534 + 1G > T, was present in all eight BBS2 patients, suggesting a founder effect. One BBS2 patient with homozygous c.534 + 1G > T mutations carried a third ciliopathic allele, TTC21B: c.264_267dupTAGA, a nonsense mutation resulting in a premature stop codon and protein truncation. CONCLUSIONS Whole exome sequencing (WES) assists in identifying molecular pathogenic variants in ciliopathic patients, as well as the genetic hotspot mutations in specific populations. It should be considered as the first-line genetic testing for heterogeneous disorders characterized by the involvement of multiple genes and diverse clinical manifestations.
Collapse
Affiliation(s)
- Yu-Wen Pan
- Department of Pediatrics, College of Medicine, National Cheng Kung University Hospital, National Cheng Kung University, No. 138, Shengli Rd., North Dist, Tainan, 70403, Taiwan, Republic of China
| | - Tsung-Ying Ou
- Department of Pediatrics, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, No. 2, Minsheng Rd., Dalin Township, Chiayi County, Chiayi, 62247, Taiwan, Republic of China
| | - Yen-Yin Chou
- Department of Pediatrics, College of Medicine, National Cheng Kung University Hospital, National Cheng Kung University, No. 138, Shengli Rd., North Dist, Tainan, 70403, Taiwan, Republic of China
- Department of Genomic Medicine, College of Medicine, National Cheng Kung University Hospital, National Cheng Kung University, No. 138, Shengli Rd., North Dist, Tainan, 70403, Taiwan, Republic of China
| | - Pao-Lin Kuo
- Department of Genomic Medicine, College of Medicine, National Cheng Kung University Hospital, National Cheng Kung University, No. 138, Shengli Rd., North Dist, Tainan, 70403, Taiwan, Republic of China
- Department of Gynecology and Obstetrics, College of Medicine, National Cheng Kung University Hospital, National Cheng Kung University, No. 138, Shengli Rd., North Dist, Tainan, 70403, Taiwan, Republic of China
- Department of Obstetrics and Gynecology, E-Da Hospital, No. 1, Yida Rd., Yanchao Dist, Kaohsiung, 824005, Taiwan, Republic of China
| | - Hui-Pin Hsiao
- Department of Pediatrics, Kaohsiung Medical University Chung Ho Memorial Hospital, No. 100, Ziyou 1st Rd., Sanmin Dist, Kaohsiung, 80756, Taiwan, Republic of China
| | - Pao-Chin Chiu
- Department of Pediatrics, Kaohsiung Veterans General Hospital, No. 386, Dazhong 1st Rd., Zuoying Dist, Kaohsiung, 813414, Taiwan, Republic of China
| | - Ju-Li Lin
- Department of Pediatrics, Chang Gung Children's Hospital, No. 5, Fuxing St., Guishan Dist, Taoyuan, 333423, Taiwan, Republic of China
| | - Fu-Sung Lo
- Department of Pediatrics, Chang Gung Children's Hospital, No. 5, Fuxing St., Guishan Dist, Taoyuan, 333423, Taiwan, Republic of China
| | - Chung-Hsing Wang
- Division of Genetics and Metabolism, Children's Hospital of China Medical University, No. 2, Yude Rd., North Dist, Taichung, 404327, Taiwan, Republic of China
- School of Medicine, China Medical University, No. 91, Xueshi Rd., North Dist, Taichung, 404328, Taiwan, Republic of China
| | - Peng-Chieh Chen
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, No. 138, Shengli Rd., North Dist, Tainan, 70403, Taiwan, Republic of China.
- Center of Clinical Medicine, College of Medicine, National Cheng Kung University Hospital, National Cheng Kung University, No. 138, Shengli Rd., North Dist, Tainan, 70403, Taiwan, Republic of China.
| | - Meng-Che Tsai
- Department of Pediatrics, College of Medicine, National Cheng Kung University Hospital, National Cheng Kung University, No. 138, Shengli Rd., North Dist, Tainan, 70403, Taiwan, Republic of China.
- Department of Genomic Medicine, College of Medicine, National Cheng Kung University Hospital, National Cheng Kung University, No. 138, Shengli Rd., North Dist, Tainan, 70403, Taiwan, Republic of China.
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, No. 138, Shengli Rd., North Dist, Tainan, 70403, Taiwan, Republic of China.
| |
Collapse
|
2
|
Gao S, Zhang Q, Ding Y, Wang L, Li Z, Hu F, Yao RE, Yu T, Chang G, Wang X. Molecular and phenotypic characteristics of Bardet-Biedl syndrome in Chinese patients. Orphanet J Rare Dis 2024; 19:149. [PMID: 38584252 PMCID: PMC11000329 DOI: 10.1186/s13023-024-03150-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 03/27/2024] [Indexed: 04/09/2024] Open
Abstract
BACKGROUND Bardet-Biedl syndrome (BBS) is a type of non-motile ciliopathy. To date, 26 genes have been reported to be associated with BBS. However, BBS is genetically heterogeneous, with significant clinical overlap with other ciliopathies, which complicates diagnosis. Disability and mortality rates are high in BBS patients; therefore, it is urgent to improve our understanding of BBS. Thus, our study aimed to describe the genotypic and phenotypic spectra of BBS in China and to elucidate genotype-phenotype correlations. METHODS Twenty Chinese patients diagnosed with BBS were enrolled in this study. We compared the phenotypes of Chinese BBS patients in this study with those from other countries to analyze the phenotypic differences across patients worldwide. In addition, genotype-phenotype correlations were described for our cohort. We also summarized all previously reported cases of BBS in Chinese patients (71 patients) and identified common and specific genetic variants in the Chinese population. RESULTS Twenty-eight variants, of which 10 are novel, in 5 different BBS-associated genes were identified in 20 Chinese BBS patients. By comparing the phenotypes of BBSome-coding genes (BBS2,7,9) with those of chaperonin-coding genes (BBS10,12), we found that patients with mutations in BBS10 and 12 had an earlier age of onset (1.10 Vs. 2.20, p < 0.01) and diagnosis (4.64 Vs. 13.17, p < 0.01), whereas patients with mutations in BBS2, 7, and 9 had a higher body mass index (28.35 Vs. 24.21, p < 0.05) and more vision problems (p < 0.05). Furthermore, in 91 Chinese BBS patients, mutations were predominant in BBS2 (28.89%) and BBS7 (15.56%), and the most frequent variants were in BBS2: c.534 + 1G > T (10/182 alleles) and BBS7: c.1002delT (7/182 alleles), marking a difference from the genotypic spectra of BBS reported abroad. CONCLUSIONS We recruited 20 Chinese patients with BBS for genetic and phenotypic analyses, and identified common clinical manifestations, pathogenic genes, and variants. We also described the phenotypic differences across patients worldwide and among different BBS-associated genes. This study involved the largest cohort of Chinese patients with BBS, and provides new insights into the distinctive clinical features of specific pathogenic variants.
Collapse
Affiliation(s)
- Shiyang Gao
- Department of Endocrinology, Metabolism and Genetics, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China
| | - Qianwen Zhang
- Department of Endocrinology, Metabolism and Genetics, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China
| | - Yu Ding
- Department of Endocrinology, Metabolism and Genetics, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China
| | - Libo Wang
- Department of Endocrinology, Metabolism and Genetics, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China
| | - Zhiying Li
- Department of Endocrinology, Metabolism and Genetics, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China
| | - Feihan Hu
- Department of Endocrinology, Metabolism and Genetics, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China
| | - Ru-En Yao
- Department of Genetic Molecular Diagnostic Laboratory, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China
| | - Tingting Yu
- Department of Genetic Molecular Diagnostic Laboratory, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China
| | - Guoying Chang
- Department of Endocrinology, Metabolism and Genetics, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China.
| | - Xiumin Wang
- Department of Endocrinology, Metabolism and Genetics, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China.
| |
Collapse
|
3
|
Xin-Yi Z, Yang-Li D, Ling-Hui Z. Review of the phenotypes and genotypes of Bardet-Biedl syndrome from China. Front Genet 2023; 14:1247557. [PMID: 38034494 PMCID: PMC10684923 DOI: 10.3389/fgene.2023.1247557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Accepted: 10/27/2023] [Indexed: 12/02/2023] Open
Abstract
Objective: To analyze the phenotypes, genotypes, and the relationship of phenotypes and genotypes for Chinese patients with Bardet-Biedl syndrome (BBS). Methods: The Chinese Wanfang and Weipu data, and PubMed were searched up to December 2022. Patients with detailed clinical feature data were involved in the analysis. Results: A total of 153 Chinese patients, including 87 males, 53 females, and 12 unknown, were enrolled. Their ages ranged from 1.2 to 44 years old with a mean of 16.70 ± 9.90 years old. Among these patients, 80 (52.29%) were reported by ophthalmologists, and only 24 (15.68%) reported by pediatricians. Most patients (132/137, 96.35%) had visual problems; 131/153 (85.62%) had polydactyly; 124/132 (93.93%) were overweight or obese; 63/114 (55.26%) had renal abnormalities; kidney dysfunction was found in 33 (21.57%); 83/104 (79.81%) had hypogonadism and/or genital hypoplasia; and 111/136 (81.62%) had mental retardation. In this series, genetic analysis was performed in 90 (58.82%) patients, including 22 BBS7 (24.71%), 20 BBS2 (22.73%), and 10 BBS10 (11.24%) patients. Moreover, 11 fetuses were diagnosed prenatally in the last 4 years except for one patient in 2004 year. It was noted that BBS7 had higher penetrance. BBS2 had higher hearing impairment and lower renal abnormality penetrance. BBS10 also had lower renal abnormality penetrance as well. Conclusion: Misdiagnosis or miss diagnosis of BBS may be common in China. In patients with polydactyly, visual impairment, obesity, renal abnormalities, hypogonadism, and mental retardation, or in fetuses with polydactyly and/or renal abnormalities, BBS should be considered in the differential diagnosis. Other deformities should be evaluated carefully and genetic analysis should be performed as early as possible.
Collapse
Affiliation(s)
- Zou Xin-Yi
- Department of Clinical Medicine, Medical School of Hangzhou City University, Hangzhou, China
| | - Dai Yang-Li
- Department of Endocrinology, The Children’s Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Zeng Ling-Hui
- Department of Clinical Medicine, Medical School of Hangzhou City University, Hangzhou, China
| |
Collapse
|
4
|
Zhong J, Xie Y, Ye H, Chen C, Sun T, Xu K, Zhang X, Li Y. Phenotypic diversity observed in a Chinese patient cohort with biallelic variants in Bardet-Biedl syndrome genes. Eye (Lond) 2023; 37:3398-3405. [PMID: 37031301 PMCID: PMC10630479 DOI: 10.1038/s41433-023-02516-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 02/19/2023] [Accepted: 03/27/2023] [Indexed: 04/10/2023] Open
Abstract
PURPOSE Bardet-Biedl syndrome (BBS) is a rare multisystem ciliopathy. The aim of this study was to describe the clinical and genetic features of a cohort of Chinese patients carrying biallelic BBS gene variants. METHODS We recruited 34 patients from 31 unrelated pedigrees who carried biallelic pathogenic variants in BBS genes. All patients underwent ophthalmic and systematic evaluations, as well as comprehensive molecular genetic analyses. Ultimately, 14 patients were followed up over time. RESULTS We identified 47 diseasing-causing variants in 10 BBS genes; 33 were novel. Diagnosis of BBS and non-syndromic retinitis pigmentosa (RP) were established in 28 patients from 27 pedigrees and 6 patients, respectively. The two most prevalent genes in patients with BBS were BBS2 and BBS4, accounting for 51.8% of the probands. The patients exhibited clinical heterogeneity, from patients with all six primary clinical components to patients suffering from non-syndromic RP. The common components were retinal dystrophy, polydactyly, and obesity, with frequencies of 78.6% to 100%, while renal anomaly frequencies were only 7.1%. Patients exhibited early and severe visual defects and retinal degeneration. Patients with biallelic missense variants in BBS2 suffered fewer clinical symptoms and mild visual impairment. Patients with BBS10 variants tended to have cone dystrophy. CONCLUSIONS Our study defined the mutated gene profiles and established the configuration of the variation frequencies for each BBS gene in Chinese patients. Overall, our patients showed early and severe visual defects and retinal degeneration. Genetic analysis is therefore crucial for diagnosis, genetic counseling, and future gene therapy in these patients.
Collapse
Affiliation(s)
- Junwei Zhong
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, China
| | - Yue Xie
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, China
| | | | - Chunjie Chen
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, China
| | - Tengyang Sun
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, China
| | - Ke Xu
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, China
| | - Xiaohui Zhang
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, China
| | - Yang Li
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, China.
| |
Collapse
|
5
|
Malvasi M, Casillo L, Avogaro F, Abbouda A, Vingolo EM. Gene Therapy in Hereditary Retinal Dystrophies: The Usefulness of Diagnostic Tools in Candidate Patient Selections. Int J Mol Sci 2023; 24:13756. [PMID: 37762059 PMCID: PMC10531171 DOI: 10.3390/ijms241813756] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 08/24/2023] [Accepted: 08/29/2023] [Indexed: 09/29/2023] Open
Abstract
PURPOSE Gene therapy actually seems to have promising results in the treatment of Leber Congenital Amaurosis and some different inherited retinal diseases (IRDs); the primary goal of this strategy is to change gene defects with a wild-type gene without defects in a DNA sequence to achieve partial recovery of the photoreceptor function and, consequently, partially restore lost retinal functions. This approach led to the introduction of a new drug (voretigene neparvovec-rzyl) for replacement of the RPE65 gene in patients affected by Leber Congenital Amaurosis (LCA); however, the treatment results are inconstant and with variable long-lasting effects due to a lack of correctly evaluating the anatomical and functional conditions of residual photoreceptors. These variabilities may also be related to host immunoreactive reactions towards the Adenovirus-associated vector. A broad spectrum of retinal dystrophies frequently generates doubt as to whether the disease or the patient is a good candidate for a successful gene treatment, because, very often, different diseases share similar genetic characteristics, causing an inconstant genotype/phenotype correlation between clinical characteristics also within the same family. For example, mutations on the RPE65 gene cause Leber Congenital Amaurosis (LCA) but also some forms of Retinitis Pigmentosa (RP), Bardet Biedl Syndrome (BBS), Congenital Stationary Night Blindness (CSNB) and Usher syndrome (USH), with a very wide spectrum of clinical manifestations. These confusing elements are due to the different pathways in which the product protein (retinoid isomer-hydrolase) is involved and, consequently, the overlapping metabolism in retinal function. Considering this point and the cost of the drug (over USD one hundred thousand), it would be mandatory to follow guidelines or algorithms to assess the best-fitting disease and candidate patients to maximize the output. Unfortunately, at the moment, there are no suggestions regarding who to treat with gene therapy. Moreover, gene therapy might be helpful in other forms of inherited retinal dystrophies, with more frequent incidence of the disease and better functional conditions (actually, gene therapy is proposed only for patients with poor vision, considering possible side effects due to the treatment procedures), in which this approach leads to better function and, hopefully, visual restoration. But, in this view, who might be a disease candidate or patient to undergo gene therapy, in relationship to the onset of clinical trials for several different forms of IRD? Further, what is the gold standard for tests able to correctly select the patient? Our work aims to evaluate clinical considerations on instrumental morphofunctional tests to assess candidate subjects for treatment and correlate them with clinical and genetic defect analysis that, often, is not correspondent. We try to define which parameters are an essential and indispensable part of the clinical rationale to select patients with IRDs for gene therapy. This review will describe a series of models used to characterize retinal morphology and function from tests, such as optical coherence tomography (OCT) and electrophysiological evaluation (ERG), and its evaluation as a primary outcome in clinical trials. A secondary aim is to propose an ancillary clinical classification of IRDs and their accessibility based on gene therapy's current state of the art. MATERIAL AND METHODS OCT, ERG, and visual field examinations were performed in different forms of IRDs, classified based on clinical and retinal conditions; compared to the gene defect classification, we utilized a diagnostic algorithm for the clinical classification based on morphofunctional information of the retina of patients, which could significantly improve diagnostic accuracy and, consequently, help the ophthalmologist to make a correct diagnosis to achieve optimal clinical results. These considerations are very helpful in selecting IRD patients who might respond to gene therapy with possible therapeutic success and filter out those in which treatment has a lower chance or no chance of positive results due to bad retinal conditions, avoiding time-consuming patient management with unsatisfactory results.
Collapse
Affiliation(s)
- Mariaelena Malvasi
- Department of Sense Organs, Faculty of Medicine and Dentistry, Sapienza University of Rome, 00185 Rome, Italy; (L.C.); (E.M.V.)
| | - Lorenzo Casillo
- Department of Sense Organs, Faculty of Medicine and Dentistry, Sapienza University of Rome, 00185 Rome, Italy; (L.C.); (E.M.V.)
| | - Filippo Avogaro
- Department of Sense Organs, Faculty of Medicine and Dentistry, Sapienza University of Rome, 00185 Rome, Italy; (L.C.); (E.M.V.)
| | - Alessandro Abbouda
- Department of Ophthalmology, Fiorini Hospital Terracina AUSL, 04019 Terracina, Italy
| | - Enzo Maria Vingolo
- Department of Sense Organs, Faculty of Medicine and Dentistry, Sapienza University of Rome, 00185 Rome, Italy; (L.C.); (E.M.V.)
- Department of Ophthalmology, Fiorini Hospital Terracina AUSL, 04019 Terracina, Italy
| |
Collapse
|
6
|
Khan S, Focșa IO, Budișteanu M, Stoica C, Nedelea F, Bohîlțea L, Caba L, Butnariu L, Pânzaru M, Rusu C, Jurcă C, Chirita-Emandi A, Bănescu C, Abbas W, Sadeghpour A, Baig SM, Bălgrădean M, Davis EE. Exome sequencing in a Romanian Bardet-Biedl syndrome cohort revealed an overabundance of causal BBS12 variants. Am J Med Genet A 2023; 191:2376-2391. [PMID: 37293956 PMCID: PMC10524726 DOI: 10.1002/ajmg.a.63322] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 05/16/2023] [Accepted: 05/26/2023] [Indexed: 06/10/2023]
Abstract
Bardet-Biedl syndrome (BBS), is an emblematic ciliopathy hallmarked by pleiotropy, phenotype variability, and extensive genetic heterogeneity. BBS is a rare (~1/140,000 to ~1/160,000 in Europe) autosomal recessive pediatric disorder characterized by retinal degeneration, truncal obesity, polydactyly, cognitive impairment, renal dysfunction, and hypogonadism. Twenty-eight genes involved in ciliary structure or function have been implicated in BBS, and explain the molecular basis for ~75%-80% of individuals. To investigate the mutational spectrum of BBS in Romania, we ascertained a cohort of 24 individuals in 23 families. Following informed consent, we performed proband exome sequencing (ES). We detected 17 different putative disease-causing single nucleotide variants or small insertion-deletions and two pathogenic exon disruptive copy number variants in known BBS genes in 17 pedigrees. The most frequently impacted genes were BBS12 (35%), followed by BBS4, BBS7, and BBS10 (9% each) and BBS1, BBS2, and BBS5 (4% each). Homozygous BBS12 p.Arg355* variants were present in seven pedigrees of both Eastern European and Romani origin. Our data show that although the diagnostic rate of BBS in Romania is likely consistent with other worldwide cohorts (74%), we observed a unique distribution of causal BBS genes, including overrepresentation of BBS12 due to a recurrent nonsense variant, that has implications for regional diagnostics.
Collapse
Affiliation(s)
- Sheraz Khan
- Stanley Manne Children's Research Institute, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA
- Human Molecular Genetics Lab, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE-C), Faisalabad, Pakistan
- Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad, Pakistan
| | - Ina Ofelia Focșa
- University of Medicine and Pharmacy "Carol Davila", Bucharest, Romania
- Cytogenomic Medical Laboratory, Bucharest, Romania
| | - Magdalena Budișteanu
- Psychiatry Research Laboratory, "Prof. Dr. Alexandru Obregia" Clinical Hospital of Psychiatry, Bucharest, Romania
- Medical Genetic Laboratory, "Victor Babeș" National Institute of Pathology, Bucharest, Romania
- Department of Medical Genetics, Faculty of Medicine, "Titu Maiorescu" University, Bucharest, Romania
| | - Cristina Stoica
- University of Medicine and Pharmacy "Carol Davila", Bucharest, Romania
- Department of Pediatrics, Clinical Institute Fundeni, Bucharest, Romania
| | - Florina Nedelea
- University of Medicine and Pharmacy "Carol Davila", Bucharest, Romania
- Genetics Department, Clinical Hospital Filantropia, Bucharest, Romania
| | | | - Lavinia Caba
- Department of Medical Genetics, "Grigore T. Popa" University of Medicine and Pharmacy, Iași, Romania
| | - Lăcrămioara Butnariu
- Department of Medical Genetics, "Grigore T. Popa" University of Medicine and Pharmacy, Iași, Romania
- Regional Medical Genetics Centre, "Sf. Maria" Children's Hospital, Iași, Romania
| | - Monica Pânzaru
- Department of Medical Genetics, "Grigore T. Popa" University of Medicine and Pharmacy, Iași, Romania
- Regional Medical Genetics Centre, "Sf. Maria" Children's Hospital, Iași, Romania
| | - Cristina Rusu
- Department of Medical Genetics, "Grigore T. Popa" University of Medicine and Pharmacy, Iași, Romania
- Regional Medical Genetics Centre, "Sf. Maria" Children's Hospital, Iași, Romania
| | - Claudia Jurcă
- Department of Genetics, Faculty of Medicine and Pharmacy, University of Oradea, Oradea, Romania
- Department of Pediatrics, "Dr. Gavril Curteanu" Municipal Clinical Hospital, Oradea, Romania
| | - Adela Chirita-Emandi
- Emergency Hospital for Children Louis Turcanu, Regional Center of Medical Genetics Timis, Timisoara, Romania
- Victor Babes University of Medicine and Pharmacy Timisoara, Department of Microscopic Morphology Genetics, Center for Genomic Medicine, Timisoara, Romania
| | - Claudia Bănescu
- "George Emil Palade" University of Medicine, Pharmacy, Sciences and Technology, Târgu Mureş, Romania
| | - Wasim Abbas
- Human Molecular Genetics Lab, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE-C), Faisalabad, Pakistan
- Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad, Pakistan
| | - Azita Sadeghpour
- Center for Human Disease Modeling, Duke University Medical Center, Durham, North Carolina, USA
- Duke Precision Medicine Program, Department of Medicine, Division of General Internal Medicine, Duke University Medical Center, Durham, NC, USA
| | - Shahid Mahmood Baig
- Pakistan Science Foundation (PSF), Islamabad, Pakistan
- Department of Biological and Biomedical Sciences, Agha Khan University Karachi, Karachi, Pakistan
| | - Mihaela Bălgrădean
- University of Medicine and Pharmacy "Carol Davila", Bucharest, Romania
- Department of Pediatrics and Pediatric Nephrology, Emergency Clinical Hospital for Children "Maria Skłodowska Curie", Bucharest, Romania
| | - Erica E Davis
- Stanley Manne Children's Research Institute, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA
- Department of Pediatrics and Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| |
Collapse
|
7
|
Gyening YK, Boris K, Cyril M, Brush RS, Nassogne MC, Agbaga MP. A novel ELOVL4 variant, L168S, causes early childhood-onset Spinocerebellar ataxia-34 and retinal dysfunction: a case report. Acta Neuropathol Commun 2023; 11:131. [PMID: 37568198 PMCID: PMC10416515 DOI: 10.1186/s40478-023-01628-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 07/22/2023] [Indexed: 08/13/2023] Open
Abstract
Spinocerebellar ataxia 34 (SCA34) is an autosomal dominant inherited disease characterized by age-related cerebellar degeneration and ataxia caused by mutations in the Elongation of Very Long Chain Fatty Acid-4 (ELOVL4) gene. The ELOVL4 enzyme catalyzes the biosynthesis of both very long chain saturated fatty acids (VLC-SFA) and very long chain polyunsaturated fatty acids (VLC-PUFA) that are important for neuronal, reproductive, and skin function. Several variants in ELOVL4 have been shown to cause different tissue-specific disorders including SCA34 with or without Erythrokeratodermia Variabilis (EKV), a skin condition characterized by dry, scaly skin, Autosomal Dominant Stargardt-Like Macular Dystrophy (STGD3), and seizures associated with neuro-ichthyotic disorders. What is puzzling is how different mutations in the same gene seem to cause different tissue-specific disorders. To date, no SCA34 patients have presented with both SCA34 and STGD3 pathology that is caused by ELOVL4 variants that cause truncation of ELOVL4. Here, we report a novel case of an early childhood onset and rapidly progressive cerebellar degeneration and retinal dysfunction in a Belgian-Italian girl who developed severe dysarthria and gait problems starting at about 3.5 years of age and progressed to immobility by 4.5 years of age. Brain magnetic resonance imaging (MRI) revealed progressive vermian, cerebellar, cortical atrophy, progressive corpus callosum slimming, and hot cross bun sign visible on the MRI. Ophthalmological examinations also revealed progressive macular dysfunction as measured by electroretinography. Using exome sequencing, we identified a novel heterozygous ELOVL4 variant, c.503 T > C (p. L168S) in the patient. To understand the enzymatic function of this novel ELOVL4 variant and how it alters the levels of VLC-PUFA and VLC-SFA biosynthesis to contribute to cerebellar and retinal dysfunction, we expressed wild-type ELOVL4 or the L168S ELOVL4 variant in cell culture and supplemented the cultures with VLC-PUFA or VLC-SFA precursors. We showed that the L168S ELOVL4 variant is deficient in the biosynthesis of VLC-SFA and VLC-PUFA. Our work suggests that differential depletion of these fatty acids may be a contributing factor to the pathogenic mechanism of SCA34 with or without EKV. Further studies will help further define how the different ELOVL4 variants cause different tissue-specific disorders with variable ages of onset.
Collapse
Affiliation(s)
- Yeboah Kofi Gyening
- Department of Cell Biology, University of Oklahoma Health Sciences Center, DMEI 423 Parke Pavilion, 608 Stanton L. Young Boulevard, Oklahoma City, OK, 73104, USA
- Department of Ophthalmology and Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, USA
- Unité Déficiences Intellectuelles/Troubles du, Développement, Service de Génétique Clinique et Médicale, AP-HP. Sorbonne Université -Hôpital de La Pitié-Salpêtrière, Paris, France
| | - Keren Boris
- UF de Génomique du Développement, Centre de Génétique Moléculaire et Chromosomique, AP-HP.Sorbonne Université - Hôpital de La Pitié-Salpêtrière, Paris, France
- Unité Déficiences Intellectuelles/Troubles du, Développement, Service de Génétique Clinique et Médicale, AP-HP. Sorbonne Université -Hôpital de La Pitié-Salpêtrière, Paris, France
| | - Mignot Cyril
- Unité Déficiences Intellectuelles/Troubles du, Développement, Service de Génétique Clinique et Médicale, AP-HP. Sorbonne Université -Hôpital de La Pitié-Salpêtrière, Paris, France
- Centre de Référence des Maladies Héréditaires du Métabolisme - Service de NeurologiePédiatrique, Cliniques Universitaires Saint-Luc -UCLouvain, Avenue Hippocrate, 10, 1200, Brussels, Belgium
| | - Richard S Brush
- Department of Cell Biology, University of Oklahoma Health Sciences Center, DMEI 423 Parke Pavilion, 608 Stanton L. Young Boulevard, Oklahoma City, OK, 73104, USA
- Department of Ophthalmology and Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, USA
- Unité Déficiences Intellectuelles/Troubles du, Développement, Service de Génétique Clinique et Médicale, AP-HP. Sorbonne Université -Hôpital de La Pitié-Salpêtrière, Paris, France
| | - Marie-Cécile Nassogne
- Centre de Référence des Maladies Héréditaires du Métabolisme - Service de NeurologiePédiatrique, Cliniques Universitaires Saint-Luc -UCLouvain, Avenue Hippocrate, 10, 1200, Brussels, Belgium.
| | - Martin-Paul Agbaga
- Department of Cell Biology, University of Oklahoma Health Sciences Center, DMEI 423 Parke Pavilion, 608 Stanton L. Young Boulevard, Oklahoma City, OK, 73104, USA.
- Department of Ophthalmology and Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, USA.
- Unité Déficiences Intellectuelles/Troubles du, Développement, Service de Génétique Clinique et Médicale, AP-HP. Sorbonne Université -Hôpital de La Pitié-Salpêtrière, Paris, France.
| |
Collapse
|
8
|
Tao T, Liu J, Wang B, Pang J, Li X, Huang L. Novel mutations in BBS genes and clinical characterization of Chinese families with Bardet-Biedl syndrome. Eur J Ophthalmol 2022; 33:11206721221136324. [PMID: 36325687 DOI: 10.1177/11206721221136324] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
PURPOSE Bardet-Biedl syndrome (BBS) is a rare autosomal-recessive inherited disorder characterized by multisystem anomalies. The objective of this study was to detect and analyse pathogenic variants in four Chinese families with BBS. METHODS Comprehensive clinical examinations were performed to investigate and evaluate the phenotypes of the affected individuals from four families. Genomic DNA was extracted from peripheral blood. Next-generation sequencing (NGS) was performed for four families, and the presence of pathogenic variants was confirmed via Sanger sequencing. RESULTS There were two males and three females with a mean age of 16.00 years. All probands displayed the primary clinical features of BBS. Mutation screening demonstrated four novel mutations: c.613C>T; p.Q205* in the BBS5 gene, c.1391C>G; p.S464* in the BBS10 gene, and c.155delC; p.S52* and c.1584T>G; p.Y528* in the BBS12 gene. Two previously reported mutations were also identified, including c.534 + 1G>T in the BBS2 gene and c.539G>A; p.G180E in the BBS10 gene. The bioinformatic analysis revealed that all the detected mutations in BBS genes were disease causing. CONCLUSIONS This study identified four novel BBS gene mutations in these Chinese families and further expanded the genotypic spectrum of BBS, thus contributing to the literature and understanding of this multisystem disease.
Collapse
Affiliation(s)
- Tianchang Tao
- Department of Ophthalmology, 71185Peking University People's Hospital, Eye Diseases and Optometry Institute, Beijing, China
- Department of Ophthalmology, Peking University People's Hospital, Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China
- College of Optometry, Peking University Health Science Center, Beijing, China
| | - Jia Liu
- Department of Ophthalmology, 71185Peking University People's Hospital, Eye Diseases and Optometry Institute, Beijing, China
- Department of Ophthalmology, Peking University People's Hospital, Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China
- College of Optometry, Peking University Health Science Center, Beijing, China
| | - Bin Wang
- Eye Research Institute, 599608Xiamen Eye Center of Xiamen University, Xiamen, China
| | - Jijing Pang
- Eye Research Institute, 599608Xiamen Eye Center of Xiamen University, Xiamen, China
| | - Xiaoxin Li
- Department of Ophthalmology, 71185Peking University People's Hospital, Eye Diseases and Optometry Institute, Beijing, China
- Department of Ophthalmology, Peking University People's Hospital, Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China
- College of Optometry, Peking University Health Science Center, Beijing, China
- Eye Research Institute, 599608Xiamen Eye Center of Xiamen University, Xiamen, China
| | - Lvzhen Huang
- Department of Ophthalmology, 71185Peking University People's Hospital, Eye Diseases and Optometry Institute, Beijing, China
- Department of Ophthalmology, Peking University People's Hospital, Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China
- College of Optometry, Peking University Health Science Center, Beijing, China
| |
Collapse
|
9
|
Shao Y, An M, Shi X, Shao L. Two novel variants in a Bardet-Biedl syndrome type 5 patient with severe renal phenotype. Nephrology (Carlton) 2022; 27:897-900. [PMID: 35951741 DOI: 10.1111/nep.14087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 07/27/2022] [Accepted: 07/31/2022] [Indexed: 11/29/2022]
Abstract
Bardet-Biedl syndrome type 5 (BBS5) has never been reported in Chinese populations. The aim of this study is to report the first BBS5 case in China, explore the phenotype and genotype correlation. The case was male, Han nationality, born with polydactyly and gained weight after birth, accompanied by polydipsia, polyuria and nocturia. He was found having low vision at the age of 7 years, and having insufficient renal function at the age of 20 years. After hospitalization, he was found to have suffered from atrophy of the whole layer of macular retina, and end stage of kidney disease, presenting with shrinking and cyst-like changes of bilateral kidneys. Whole-exome sequencing was performed among the proband and his parents (Trios), further validated using Sanger sequencing and quantitative polymerase chain reaction. Two novel compound heterozygous variants of BBS5 gene [a missense variant NC_000002.12, NM_152384.3:c.1A>G(p.Met1?)& a large deletion c.(?_-60)_(386+1_387-1)del] were detected. BBS is rare, whereas BBS5 is rarer. Herein, we reported a Chinese BBS5 patient with severe renal phenotype and identified two novel BBS5 variants. This article is protected by copyright. All rights reserved.
Collapse
Affiliation(s)
- Yingfei Shao
- Wenzhou Medical University Renji college, Wenzhou, China
| | - Ming An
- Department of Ophthalmology, Qingdao Municipal Hospital Affiliated Qingdao University, Qingdao, China
| | - Xiaomeng Shi
- Department of Nephrology, Qingdao Municipal Hospital Affiliated Qingdao University, Qingdao, China
| | - Leping Shao
- Department of Nephrology, Qingdao Municipal Hospital Affiliated Qingdao University, Qingdao, China
| |
Collapse
|
10
|
Nasser F, Kohl S, Kurtenbach A, Kempf M, Biskup S, Zuleger T, Haack TB, Weisschuh N, Stingl K, Zrenner E. Ophthalmic and Genetic Features of Bardet Biedl Syndrome in a German Cohort. Genes (Basel) 2022; 13:genes13071218. [PMID: 35886001 PMCID: PMC9322102 DOI: 10.3390/genes13071218] [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: 05/15/2022] [Revised: 06/29/2022] [Accepted: 07/02/2022] [Indexed: 12/04/2022] Open
Abstract
The aim of this study was to characterize the ophthalmic and genetic features of Bardet Biedl (BBS) syndrome in a cohort of patients from a German specialized ophthalmic care center. Sixty-one patients, aged 5−56 years, underwent a detailed ophthalmic examination including visual acuity and color vision testing, electroretinography (ERG), visually evoked potential recording (VEP), fundus examination, and spectral domain optical coherence tomography (SD-OCT). Adaptive optics flood illumination ophthalmoscopy was performed in five patients. All patients had received diagnostic genetic testing and were selected upon the presence of apparent biallelic variants in known BBS-associated genes. All patients had retinal dystrophy with morphologic changes of the retina. Visual acuity decreased from ~0.2 (decimal) at age 5 to blindness 0 at 50 years. Visual field examination could be performed in only half of the patients and showed a concentric constriction with remaining islands of function in the periphery. ERG recordings were mostly extinguished whereas VEP recordings were reduced in about half of the patients. The cohort of patients showed 51 different likely biallelic mutations—of which 11 are novel—in 12 different BBS-associated genes. The most common associated genes were BBS10 (32.8%) and BBS1 (24.6%), and by far the most commonly observed variants were BBS10 c.271dup;p.C91Lfs*5 (21 alleles) and BBS1 c.1169T>G;p.M390R (18 alleles). The phenotype associated with the different BBS-associated genes and genotypes in our cohort is heterogeneous, with diverse features without genotype−phenotype correlation. The results confirm and expand our knowledge of this rare disease.
Collapse
Affiliation(s)
- Fadi Nasser
- Centre for Ophthalmology, University of Tübingen, 72076 Tuebingen, Germany; (S.K.); (A.K.); (M.K.); (N.W.); (K.S.); (E.Z.)
- Department of Ophthalmology, University of Leipzig, 04103 Leipzig, Germany
- Correspondence:
| | - Susanne Kohl
- Centre for Ophthalmology, University of Tübingen, 72076 Tuebingen, Germany; (S.K.); (A.K.); (M.K.); (N.W.); (K.S.); (E.Z.)
| | - Anne Kurtenbach
- Centre for Ophthalmology, University of Tübingen, 72076 Tuebingen, Germany; (S.K.); (A.K.); (M.K.); (N.W.); (K.S.); (E.Z.)
| | - Melanie Kempf
- Centre for Ophthalmology, University of Tübingen, 72076 Tuebingen, Germany; (S.K.); (A.K.); (M.K.); (N.W.); (K.S.); (E.Z.)
- Center for Rare Eye Diseases, University of Tübingen, 72076 Tuebingen, Germany
| | | | - Theresia Zuleger
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, 72076 Tuebingen, Germany; (T.Z.); (T.B.H.)
| | - Tobias B. Haack
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, 72076 Tuebingen, Germany; (T.Z.); (T.B.H.)
| | - Nicole Weisschuh
- Centre for Ophthalmology, University of Tübingen, 72076 Tuebingen, Germany; (S.K.); (A.K.); (M.K.); (N.W.); (K.S.); (E.Z.)
| | - Katarina Stingl
- Centre for Ophthalmology, University of Tübingen, 72076 Tuebingen, Germany; (S.K.); (A.K.); (M.K.); (N.W.); (K.S.); (E.Z.)
- Center for Rare Eye Diseases, University of Tübingen, 72076 Tuebingen, Germany
| | - Eberhart Zrenner
- Centre for Ophthalmology, University of Tübingen, 72076 Tuebingen, Germany; (S.K.); (A.K.); (M.K.); (N.W.); (K.S.); (E.Z.)
- Werner Reichardt Centre for Integrative Neuroscience (CIN), University of Tübingen, 72076 Tuebingen, Germany
| |
Collapse
|
11
|
Ocular Characteristics of Patients with Leber Congenital Amaurosis 6 Caused by Pathogenic RPGRIP1 Gene Variation in a Chinese Cohort. J Ophthalmol 2021; 2021:9966427. [PMID: 34796026 PMCID: PMC8595035 DOI: 10.1155/2021/9966427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 10/13/2021] [Indexed: 11/17/2022] Open
Abstract
Purpose To delineate the clinical and genetic characteristics of Chinese patients with RPGRIP1-associated Leber congenital amaurosis 6 (LCA6). Methods After screening 352 unrelated families with clinically diagnosed RP, five LCA6 patients with RPGRIP1 variations from unrelated Chinese families were identified. Full ophthalmology examinations, including decimal best-corrected visual acuity (BCVA), fundus photography, fundus autofluorescence imaging, spectral-domain optical coherence tomography (SD-OCT), full-field electroretinography (ffERG), multifocal electroretinography (mfERG), perimetry, and flash visual evoked potential (FVEP), were performed. Target next-generation sequencing (NGS) and Sanger sequencing were performed for the five patients to identify and to validate candidate disease-causing variants. Results Five patients were molecularly diagnosed as the LCA6 associated with RPGRIP1 variation, with typical clinical characteristics including congenital night blindness, nystagmus, and visual defect, at an early age. Interestingly, LCA6 exhibited extensive clinical heterogeneity and the changes in the morphology and function were not completely consistent in the five LCA6 patients. Case 1 showed extensive inferior-nasal retinal atrophy with a corresponding area of hypofluorescence in fundus autofluorescence, and the fundus photograph was nearly normal in cases 2 and 3. The ERG results displayed a moderately reduced rod-system response in cases 1 and 2 and a significant reduced rod-system response in case 3. Both case 4 and case 5 showed mottled pigmentation in fundi and an unrecordable rod and cone-system response in ERG. Moreover, we identified eight compound variants and one homozygous variant in the five patients with RPGRIP1. Conclusions This is the largest report focused on the clinical electrophysiological features of patients with associated LCA6 caused by the variation in the RPGRIP1 gene in the Chinese population with an enriched phenotypic and genotypic background of LCA6 to improve future gene therapies.
Collapse
|