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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.
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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.
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Deitch I, Itskov S, Panneman D, Abu Shtaya A, Saban T, Goldberg Y, Ehrenberg M, Cremers FPM, Roosing S, Ben-Yosef T. Autosomal Recessive Rod-Cone Dystrophy with Mild Extra-Ocular Manifestations Due to a Splice-Affecting Variant in BBS9. Curr Issues Mol Biol 2024; 46:2566-2575. [PMID: 38534779 DOI: 10.3390/cimb46030163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 03/14/2024] [Accepted: 03/14/2024] [Indexed: 03/28/2024] Open
Abstract
Bardet-Biedl syndrome (BBS), one of the most common forms of syndromic inherited retinal diseases (IRDs), is characterized by the combination of retinal degeneration with additional extra-ocular manifestations, including obesity, intellectual disability, kidney disease, polydactyly and other skeletal abnormalities. We observed an Israeli patient with autosomal recessive apparently non-syndromic rod-cone dystrophy (RCD). Extra-ocular findings were limited to epilepsy and dental problems. Genetic analysis with a single molecule molecular inversion probes-based panel that targets the exons and splice sites of 113 genes associated with retinitis pigmentosa and Leber congenital amaurosis revealed a homozygous rare missense variant in the BBS9 gene (c.263C>T;p.(Ser88Leu)). This variant, which affects a highly conserved amino acid, is also located in the last base of Exon 3, and predicted to be splice-altering. An in vitro minigene splice assay demonstrated that this variant leads to the partial aberrant splicing of Exon 3. Therefore, we suggest that this variant is likely hypomorphic. This is in agreement with the relatively mild phenotype observed in the patient. Hence, the findings in our study expand the phenotypic spectrum associated with BBS9 variants and indicate that variants in this gene should be considered not only in BBS patients but also in individuals with non-syndromic IRD or IRD with very mild extra-ocular manifestations.
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Affiliation(s)
- Iris Deitch
- Rabin Medical Center, Department of Ophthalmology, Petach Tikva 4941492, Israel
- Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Sofia Itskov
- Ruth & Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa 3109601, Israel
| | - Daan Panneman
- Department of Human Genetics, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Aasem Abu Shtaya
- Raphael Recanati Genetic Institute, Rabin Medical Center, Beilinson Hospital, Petach Tikva 4941492, Israel
- Unit of Gastroenterology, Carmel Medical Center, Haifa 3436212, Israel
| | - Tal Saban
- Rabin Medical Center, Department of Ophthalmology, Petach Tikva 4941492, Israel
- Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Yael Goldberg
- Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
- Raphael Recanati Genetic Institute, Rabin Medical Center, Beilinson Hospital, Petach Tikva 4941492, Israel
| | - Miriam Ehrenberg
- Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
- Schneider Children's Medical Center of Israel, Department of Ophthalmology, Petach Tikva 4920235, Israel
| | - Frans P M Cremers
- Department of Human Genetics, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Susanne Roosing
- Department of Human Genetics, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Tamar Ben-Yosef
- Ruth & Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa 3109601, Israel
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Feizabadi MH, Alerasool M, Eslahi A, Esmaeilzadeh E, Mehrjardi MYV, Saket M, Farokhi S, Fattahi Z, Khorshid HRK, Mojarrad M. Characterizing Homozygous Variants in Bardet-Biedl Syndrome-Associated Genes Within Iranian Families: Unveiling a Founder Variant in BBS2, c.471G>A. Biochem Genet 2024:10.1007/s10528-023-10637-w. [PMID: 38407766 DOI: 10.1007/s10528-023-10637-w] [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: 10/14/2023] [Accepted: 12/12/2023] [Indexed: 02/27/2024]
Abstract
Bardet-Biedl syndrome (BBS) is a rare inherited ciliopathy disorder characterized by a broad spectrum of clinical symptoms such as retinal dystrophy, obesity, polydactyly, genitourinary and kidney anomalies, learning disability, and hypogonadism. The understanding of the variants involved in BBS-causing genes remains incomplete, highlighting the need for further research to develop a molecular diagnostic strategy for this syndrome. Singleton whole-exome sequencing (WES) was performed on sixteen patients. Our study revealed (1) nine patients carried eight homozygous pathogenic variants with four of them being novel (2) Specifically, a synonymous splicing variant (c.471G > A) in BBS2 gene in six patients with Baloch ethnicity. The identification of runs of homozygosity (ROH) calling was performed using the BCFtools/RoH software on WES data of patients harboring c.471G > A variant. The presence of shared homozygous regions containing the identified variant was confirmed in these patients. In-silico analysis predicted the effect of the c.471G > A variants on BBS2 mRNA splicing. This variant results in disrupted wild-type donor site and intron retention in the mature mRNA. (3) And a deletion of exons 14 to 17 in the BBS1 gene was identified in one patient by Copy-Number Variation (CNV) analysis using the ExomeDepth pipeline. Our results identified the founder variant c.471G > A in the BBS2 gene in the Baloch ethnicity of the Iranian population. This finding can guide the diagnostic approach of this syndrome in future studies.
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Affiliation(s)
| | - Masoome Alerasool
- Genetic Foundation of Khorasan Razavi, Mashhad, Iran
- Faculty of Medicine, Department of Medical Genetics, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Atieh Eslahi
- Faculty of Medicine, Department of Medical Genetics, Mashhad University of Medical Sciences, Mashhad, Iran
| | | | | | - Mitra Saket
- RP Eye Patients Supporting Institute, Tehran, Iran
| | - Shima Farokhi
- Faculty of Medicine, Department of Medical Genetics, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Zohreh Fattahi
- Genetics Research Centre, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | | | - Majid Mojarrad
- Faculty of Medicine, Department of Medical Genetics, Mashhad University of Medical Sciences, Mashhad, Iran.
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Long P, Wang L, Tan H, Quan R, Hu Z, Zeng M, Deng Z, Huang H, Greenbaum J, Deng H, Xiao H. Oligogenic basis of premature ovarian insufficiency: an observational study. J Ovarian Res 2024; 17:32. [PMID: 38310280 PMCID: PMC10837925 DOI: 10.1186/s13048-024-01351-1] [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: 09/23/2023] [Accepted: 01/13/2024] [Indexed: 02/05/2024] Open
Abstract
BACKGROUND The etiology of premature ovarian insufficiency, that is, the loss of ovarian activity before 40 years of age, is complex. Studies suggest that genetic factors are involved in 20-25% of cases. The aim of this study was to explore the oligogenic basis of premature ovarian insufficiency. RESULTS Whole-exome sequencing of 93 patients with POI and whole-genome sequencing of 465 controls were performed. In the gene-burden analysis, multiple genetic variants, including those associated with DNA damage repair and meiosis, were more common in participants with premature ovarian insufficiency than in controls. The ORVAL-platform analysis confirmed the pathogenicity of the RAD52 and MSH6 combination. CONCLUSIONS The results of this study indicate that oligogenic inheritance is an important cause of premature ovarian insufficiency and provide insights into the biological mechanisms underlying premature ovarian insufficiency.
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Affiliation(s)
- Panpan Long
- Institute of Reproductive & Stem Cell Engineering, School of Basic Medical Science, Central South University, 88 Xiangya Road, Changsha, 410008, Hunan, China
- Center of Reproductive Health, School of Basic Medical Science, Central South University, Changsha, China
| | - Le Wang
- Institute of Reproductive & Stem Cell Engineering, School of Basic Medical Science, Central South University, 88 Xiangya Road, Changsha, 410008, Hunan, China
- Center of Reproductive Health, School of Basic Medical Science, Central South University, Changsha, China
- Biomedical Research Center, Hunan University of Medicine, Huaihua, China
| | - Hangjing Tan
- Institute of Reproductive & Stem Cell Engineering, School of Basic Medical Science, Central South University, 88 Xiangya Road, Changsha, 410008, Hunan, China
- Center of Reproductive Health, School of Basic Medical Science, Central South University, Changsha, China
| | - Ruping Quan
- Institute of Reproductive & Stem Cell Engineering, School of Basic Medical Science, Central South University, 88 Xiangya Road, Changsha, 410008, Hunan, China
- Center of Reproductive Health, School of Basic Medical Science, Central South University, Changsha, China
| | - Zihao Hu
- Institute of Reproductive & Stem Cell Engineering, School of Basic Medical Science, Central South University, 88 Xiangya Road, Changsha, 410008, Hunan, China
- Center of Reproductive Health, School of Basic Medical Science, Central South University, Changsha, China
| | - Minghua Zeng
- Institute of Reproductive & Stem Cell Engineering, School of Basic Medical Science, Central South University, 88 Xiangya Road, Changsha, 410008, Hunan, China
- Center of Reproductive Health, School of Basic Medical Science, Central South University, Changsha, China
| | - Ziheng Deng
- Institute of Reproductive & Stem Cell Engineering, School of Basic Medical Science, Central South University, 88 Xiangya Road, Changsha, 410008, Hunan, China
- Center of Reproductive Health, School of Basic Medical Science, Central South University, Changsha, China
| | - Hualin Huang
- Reproductive Medicine Center, Department of Obstetrics and Gynecology, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Jonathan Greenbaum
- Center of Biomedical Informatics and Genomics, Deming Department of Medicine, Tulane University School of Medicine, New Orleans, LA, USA
| | - Hongwen Deng
- Center of Biomedical Informatics and Genomics, Deming Department of Medicine, Tulane University School of Medicine, New Orleans, LA, USA
| | - Hongmei Xiao
- Institute of Reproductive & Stem Cell Engineering, School of Basic Medical Science, Central South University, 88 Xiangya Road, Changsha, 410008, Hunan, China.
- Center of Reproductive Health, School of Basic Medical Science, Central South University, Changsha, China.
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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.
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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
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Petzold F, Schönauer R, Werner A, Halbritter J. Clinical and Functional Assessment of Digenicity in Renal Phosphate Wasting. Nutrients 2023; 15:2081. [PMID: 37432176 DOI: 10.3390/nu15092081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 04/21/2023] [Accepted: 04/24/2023] [Indexed: 07/12/2023] Open
Abstract
Apart from increased fluid intake, patients with kidney stone disease (KSD) due to renal phosphate wasting require specific metaphylaxis. NaPi2a, NaPi2c, and NHERF1 regulate plasma phosphate concentration by reabsorbing phosphate in proximal kidney tubules and have been found altered in monogenic hypophosphatemia with a risk of KSD. In this study, we aimed at assessing the combined genetic alterations impacting NaPi2a, NaPi2c, and NHERF1. Therefore, we screened our hereditary KSD registry for cases of oligo- and digenicity, conducted reverse phenotyping, and undertook functional studies. As a result, we identified three patients from two families with digenic alterations in NaPi2a, NaPi2c, and NHERF1. In family 1, the index patient, who presented with severe renal calcifications and a bone mineralization disorder, carried digenic alterations affecting both NaPi transporter 2a and 2c. Functional analysis confirmed an additive genetic effect. In family 2, the index patient presented with kidney function decline, distinct musculature-related symptoms, and intracellular ATP depletion. Genetically, this individual was found to harbor variants in both NaPi2c and NHERF1 pointing towards genetic interaction. In summary, digenicity and gene dosage are likely to impact the severity of renal phosphate wasting and should be taken into account in terms of metaphylaxis through phosphate substitution.
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Affiliation(s)
- Friederike Petzold
- Division of Nephrology, University of Leipzig Medical Center, 04103 Leipzig, Germany
| | - Ria Schönauer
- Division of Nephrology, University of Leipzig Medical Center, 04103 Leipzig, Germany
- Department of Nephrology, Charité Universitätsmedizin Berlin, 10117 Berlin, Germany
| | - Andreas Werner
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Jan Halbritter
- Division of Nephrology, University of Leipzig Medical Center, 04103 Leipzig, Germany
- Department of Nephrology, Charité Universitätsmedizin Berlin, 10117 Berlin, Germany
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Lazareva J, Brady SM, Yanovski JA. An evaluation of setmelanotide injection for chronic weight management in adult and pediatric patients with obesity due to Bardet-Biedl syndrome. Expert Opin Pharmacother 2023; 24:667-674. [PMID: 37013719 PMCID: PMC10121918 DOI: 10.1080/14656566.2023.2199152] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 03/31/2023] [Indexed: 04/05/2023]
Abstract
INTRODUCTION Bardet-Biedl Syndrome (BBS) is a rare, multisystemic ciliopathy with an incidence of obesity of 89%. Mutations in genes encoding BBS proteins are linked to reduced leptin sensitivity of hypothalamic POMC neurons and reduced activation of the melanocortin-4 receptor (MC4R) pathway due to deficient α-MSH production by hypothalamic POMC neurons. The MC4R pathway is involved in controlling body weight and energy metabolism, and its disruption is linked to hyperphagia and obesity. Setmelanotide is an MC4R agonist that counteracts deficiencies in the MC4R pathway of individuals with BBS. AREAS COVERED Data from clinical trials were reviewed along with information available from setmelanotide's approval for treatment of obesity in people ages ≥6y with a clinical diagnosis of BBS. EXPERT OPINION Setmelanotide is available as a daily injectable that can be used for amelioration of obesity in people with Bardet-Biedl syndrome. Its cost is substantial, which may limit its use, but among those who respond, setmelanotide can reduce body mass dramatically and potentially improve comorbid conditions associated with obesity. Setmelanotide treatment has generally tolerable side effects, primarily injection site reactions and nausea/vomiting that generally improve with continued use; almost all people using setmelanotide experience marked skin darkening due to off-target activation of cutaneous MC1R.
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Affiliation(s)
- Julia Lazareva
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, Section on Growth and Obesity, Maryland, United States
| | - Sheila M. Brady
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, Section on Growth and Obesity, Maryland, United States
| | - Jack A. Yanovski
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, Section on Growth and Obesity, Maryland, United States
- The National Institutes of Health, Maryland, United States
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