1
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Cevik S, Zhao P, Zorluer A, Pir MS, Bian W, Kaplan OI. Matching variants for functional characterization of genetic variants. G3 (BETHESDA, MD.) 2023; 13:jkad227. [PMID: 37933433 PMCID: PMC10700107 DOI: 10.1093/g3journal/jkad227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 09/06/2023] [Indexed: 11/08/2023]
Abstract
Rapid and low-cost sequencing, as well as computer analysis, have facilitated the diagnosis of many genetic diseases, resulting in a substantial rise in the number of disease-associated genes. However, genetic diagnosis of many disorders remains problematic due to the lack of interpretation for many genetic variants, especially missenses, the infeasibility of high-throughput experiments on mammals, and the shortcomings of computational prediction technologies. Additionally, the available mutant databases are not well-utilized. Toward this end, we used Caenorhabditis elegans mutant resources to delineate the functions of eight missense variants (V444I, V517D, E610K, L732F, E817K, H873P, R1105K, and G1205E) and two stop codons (W937stop and Q1434stop), including several matching variants (MatchVar) with human in ciliopathy associated IFT-140 (also called CHE-11)//IFT140 (intraflagellar transport protein 140). Moreover, MatchVars carrying C. elegans mutants, including IFT-140(G680S) and IFT-140(P702A) for the human (G704S) (dbSNP: rs150745099) and P726A (dbSNP: rs1057518064 and a conflicting variation) were created using CRISPR/Cas9. IFT140 is a key component of IFT complex A (IFT-A), which is involved in the retrograde transport of IFT along cilia and the entrance of G protein-coupled receptors into cilia. Functional analysis of all 10 variants revealed that P702A and W937stop, but not others phenocopied the ciliary phenotypes (short cilia, IFT accumulations, mislocalization of membrane proteins, and cilia entry of nonciliary proteins) of the IFT-140 null mutant, indicating that both P702A and W937stop are phenotypic in C. elegans. Our functional data offered experimental support for interpreting human variants, by using ready-to-use mutants carrying MatchVars and generating MatchVars with CRISPR/Cas9.
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Affiliation(s)
- Sebiha Cevik
- Rare Disease Laboratory, School of Life and Natural Sciences, Abdullah Gul University, Kayseri 38080, Turkey
| | - Pei Zhao
- School of Applied Science and Engineering, Fuzhou Institute of Technology, Fuzhou 350014, China
- SunyBiotech Co., Ltd., Fuzhou 35000, China
| | - Atiyye Zorluer
- Rare Disease Laboratory, School of Life and Natural Sciences, Abdullah Gul University, Kayseri 38080, Turkey
| | - Mustafa S Pir
- Rare Disease Laboratory, School of Life and Natural Sciences, Abdullah Gul University, Kayseri 38080, Turkey
| | | | - Oktay I Kaplan
- Rare Disease Laboratory, School of Life and Natural Sciences, Abdullah Gul University, Kayseri 38080, Turkey
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2
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Francis RJB, San Agustin JT, Szabo Rogers HL, Cui C, Jonassen JA, Eguether T, Follit JA, Lo CW, Pazour GJ. Autonomous and non-cell autonomous role of cilia in structural birth defects in mice. PLoS Biol 2023; 21:e3002425. [PMID: 38079449 PMCID: PMC10735189 DOI: 10.1371/journal.pbio.3002425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 12/21/2023] [Accepted: 11/09/2023] [Indexed: 12/21/2023] Open
Abstract
Ciliopathies are associated with wide spectrum of structural birth defects (SBDs), indicating important roles for cilia in development. Here, we provide novel insights into the temporospatial requirement for cilia in SBDs arising from deficiency in Ift140, an intraflagellar transport (IFT) protein regulating ciliogenesis. Ift140-deficient mice exhibit cilia defects accompanied by wide spectrum of SBDs including macrostomia (craniofacial defects), exencephaly, body wall defects, tracheoesophageal fistula (TEF), randomized heart looping, congenital heart defects (CHDs), lung hypoplasia, renal anomalies, and polydactyly. Tamoxifen inducible CAGGCre-ER deletion of a floxed Ift140 allele between E5.5 to 9.5 revealed early requirement for Ift140 in left-right heart looping regulation, mid to late requirement for cardiac outflow septation and alignment, and late requirement for craniofacial development and body wall closure. Surprisingly, CHD were not observed with 4 Cre drivers targeting different lineages essential for heart development, but craniofacial defects and omphalocele were observed with Wnt1-Cre targeting neural crest and Tbx18-Cre targeting epicardial lineage and rostral sclerotome through which trunk neural crest cells migrate. These findings revealed cell autonomous role of cilia in cranial/trunk neural crest-mediated craniofacial and body wall closure defects, while non-cell autonomous multi-lineage interactions underlie CHD pathogenesis, revealing unexpected developmental complexity for CHD associated with ciliopathies.
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Affiliation(s)
- Richard J. B. Francis
- Department of Developmental Biology, University of Pittsburgh, Rangos Research Center, Pittsburgh, Pennsylvania, United States of America
- Discipline of Biomedical Sciences and Molecular Biology; College of Public Health, Medical and Veterinary Science, James Cook University, Townsville, Australia
| | - Jovenal T. San Agustin
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, United States of America
| | - Heather L. Szabo Rogers
- Department of Developmental Biology, University of Pittsburgh, Rangos Research Center, Pittsburgh, Pennsylvania, United States of America
- Center for Craniofacial Regeneration, Department of Oral Biology, School of Dental Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Cheng Cui
- Department of Developmental Biology, University of Pittsburgh, Rangos Research Center, Pittsburgh, Pennsylvania, United States of America
| | - Julie A. Jonassen
- Department of Microbiology and Physiological Systems, University of Massachusetts Chan Medical School, Worcester, Massachusetts, United States of America
| | - Thibaut Eguether
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, United States of America
| | - John A. Follit
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, United States of America
| | - Cecilia W. Lo
- Department of Developmental Biology, University of Pittsburgh, Rangos Research Center, Pittsburgh, Pennsylvania, United States of America
| | - Gregory J. Pazour
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, United States of America
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3
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Sharova M, Markova T, Sumina M, Petukhova M, Bulakh M, Ryzhkova O, Nagornova T, Ionova S, Marakhonov A, Dadali E, Kutsev S. Rare IFT140-Associated Phenotype of Cranioectodermal Dysplasia and Features of Diagnostic Journey in Patients with Suspected Ciliopathies. Genes (Basel) 2023; 14:1553. [PMID: 37628605 PMCID: PMC10454909 DOI: 10.3390/genes14081553] [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: 06/20/2023] [Revised: 07/21/2023] [Accepted: 07/26/2023] [Indexed: 08/27/2023] Open
Abstract
Here we present a patient with a cranioectodermal phenotype associated with pathogenic variants in the IFT140 gene. Most frequently, pathogenic variants in IFT140 correspond to the phenotype of Mainzer-Saldino syndrome. Only four patients have previously been described with this cranioectodermal phenotype and variants in IFT140. In comparison to other IFT140-cranioectodermal patients, our proband had similar skeletal features among with early onset end-stage renal failure that required kidney transplantation but did not have common ophthalmological features such as retinopathy, optic nerve atrophy, or nystagmus. Following exome sequencing, a splicing variant and exons 27-30 tandem duplication were suspected and further validated. The two other patients with Mainzer-Saldino syndrome that we described displayed a typical clinical picture but a special diagnostic journey. In both cases, at first only one pathogenic variant was detected following panel or exome NGS sequencing. Further WGS was performed for one of them where tandem duplication was found. Screening the third patient for the same tandem duplication was successful and revealed the presence of this duplication. Thus, we suggest that the description of the clinical feature polymorphism in a rare IFT140-cranioectodermal phenotype is extremely important for providing genetic counseling for families, as well as the formation of the correct diagnostic path for patients with a variant in IFT140.
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Affiliation(s)
| | | | - Maria Sumina
- State Healthcare Institution of Sverdlovsk Region “Clinical and Diagnostic Center “Mother’s and Child Health Protection”, 620067 Ekaterinburg, Russia
| | | | - Maria Bulakh
- Research Centre for Medical Genetics, 115522 Moscow, Russia
| | - Oxana Ryzhkova
- Research Centre for Medical Genetics, 115522 Moscow, Russia
| | | | - Sofya Ionova
- Research Centre for Medical Genetics, 115522 Moscow, Russia
| | | | - Elena Dadali
- Research Centre for Medical Genetics, 115522 Moscow, Russia
| | - Sergey Kutsev
- Research Centre for Medical Genetics, 115522 Moscow, Russia
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4
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Francis R, San Agustin JT, Szabo Rogers HL, Cui C, Jonassen JA, Eguether T, Follit JA, Lo CW, Pazour GJ. Autonomous and non-cell autonomous etiology of ciliopathy associated structural birth defects. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.07.544132. [PMID: 37333142 PMCID: PMC10274801 DOI: 10.1101/2023.06.07.544132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Ciliopathies are associated with wide spectrum of structural birth defects (SBD), indicating important roles for cilia in development. Here we provide novel insights into the temporospatial requirement for cilia in SBDs arising from deficiency in Ift140 , an intraflagellar transport protein regulating ciliogenesis. Ift140 deficient mice exhibit cilia defects accompanied by wide spectrum of SBDs including macrostomia (craniofacial defects), exencephaly, body wall defects, tracheoesophageal fistula, randomized heart looping, congenital heart defects (CHD), lung hypoplasia, renal anomalies, and polydactyly. Tamoxifen inducible CAG-Cre deletion of a floxed Ift140 allele between E5.5 to 9.5 revealed early requirement for Ift140 in left-right heart looping regulation, mid to late requirement for cardiac outflow septation and alignment, and late requirement for craniofacial development and body wall closure. Surprisingly, CHD was not observed with four Cre drivers targeting different lineages essential for heart development, but craniofacial defects and omphalocele were observed with Wnt1-Cre targeting neural crest and Tbx18-Cre targeting epicardial lineage and rostral sclerotome through which trunk neural crest cells migrate. These findings revealed cell autonomous role of cilia in cranial/trunk neural crest mediated craniofacial and body wall closure defects, while non-cell autonomous multi-lineage interactions underlie CHD pathogenesis, revealing unexpected developmental complexity for CHD associated with ciliopathy.
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5
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Zhang X, Zhou J, Wang X, Geng J, Chen Y, Sun Y. IFT140 +/K14 + cells function as stem/progenitor cells in salivary glands. Int J Oral Sci 2022; 14:49. [PMID: 36216809 PMCID: PMC9550827 DOI: 10.1038/s41368-022-00200-5] [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: 05/04/2022] [Revised: 07/31/2022] [Accepted: 09/05/2022] [Indexed: 11/27/2022] Open
Abstract
Stem/progenitor cells are important for salivary gland development, homeostasis maintenance, and regeneration following injury. Keratin-14+ (K14+) cells have been recognized as bona fide salivary gland stem/progenitor cells. However, K14 is also expressed in terminally differentiated myoepithelial cells; therefore, more accurate molecular markers for identifying salivary stem/progenitor cells are required. The intraflagellar transport (IFT) protein IFT140 is a core component of the IFT system that functions in signaling transduction through the primary cilia. It is reportedly expressed in mesenchymal stem cells and plays a role in bone formation. In this study, we demonstrated that IFT140 was intensively expressed in K14+ stem/progenitor cells during the developmental period and early regeneration stage following ligation-induced injuries in murine submandibular glands. In addition, we demonstrated that IFT140+/ K14+ could self-renew and differentiate into granular duct cells at the developmental stage in vivo. The conditional deletion of Ift140 from K14+ cells caused abnormal epithelial structure and function during salivary gland development and inhibited regeneration. IFT140 partly coordinated the function of K14+ stem/progenitor cells by modulating ciliary membrane trafficking. Our investigation identified a combined marker, IFT140+/K14+, for salivary gland stem/progenitor cells and elucidated the essential role of IFT140 and cilia in regulating salivary stem/progenitor cell differentiation and gland regeneration.
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Affiliation(s)
- Xueming Zhang
- Department of Oral and Maxillofacial Surgery, Stomatological Hospital and Dental School of Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, No. 399, YanChang Middle Road, Shanghai, China
| | - Ji Zhou
- Department of Implantology, Stomatological Hospital and Dental School of Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, No. 399, YanChang Middle Road, Shanghai, China
| | - Xinyu Wang
- Department of Implantology, Stomatological Hospital and Dental School of Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, No. 399, YanChang Middle Road, Shanghai, China
| | - Jiangyu Geng
- Department of Implantology, Stomatological Hospital and Dental School of Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, No. 399, YanChang Middle Road, Shanghai, China
| | - Yubei Chen
- Department of Implantology, Stomatological Hospital and Dental School of Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, No. 399, YanChang Middle Road, Shanghai, China
| | - Yao Sun
- Department of Implantology, Stomatological Hospital and Dental School of Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, No. 399, YanChang Middle Road, Shanghai, China.
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Walczak-Sztulpa J, Wawrocka A, Sikora W, Pawlak M, Bukowska-Olech E, Kopaczewski B, Urzykowska A, Arts HH, Gotz-Więckowska A, Grenda R, Latos-Bieleńska A, Glazar R. WDR35 variants in a cranioectodermal dysplasia patient with early onset end-stage renal disease and retinal dystrophy. Am J Med Genet A 2022; 188:3071-3077. [PMID: 35875935 DOI: 10.1002/ajmg.a.62903] [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] [Received: 02/16/2022] [Revised: 05/16/2022] [Accepted: 05/22/2022] [Indexed: 01/31/2023]
Abstract
Cranioectodermal dysplasia (CED) is rare heterogeneous condition. It belongs to a group of disorders defined as ciliopathies and is associated with defective cilia function and structure. To date six genes have been associated with CED. Here we describe a 4-year-old male CED patient whose features include dolichocephaly, multi-suture craniosynostosis, epicanthus, frontal bossing, narrow thorax, limb shortening, and brachydactyly. The patient presented early-onset chronic kidney disease and was transplanted at the age of 2 years and 5 months. At the age of 3.5 years a retinal degeneration was diagnosed. Targeted sequencing by NGS revealed the presence of compound heterozygous variants in the WDR35 gene. The variants are a novel missense change in exon 9 p.(Gly303Arg) and a previously described nonsense variant in exon 18 p.(Leu641*). Our findings suggest that patients with WDR35 defects may be at risk to develop early-onset retinal degeneration. Therefore, CED patients with pathogenic variation in this gene should be assessed at least once by the ophthalmologist before the age of 4 years to detect early signs of retinal degeneration.
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Affiliation(s)
| | - Anna Wawrocka
- Department of Medical Genetics, Poznan University of Medical Sciences, Poznan, Poland
| | - Weronika Sikora
- Students' Scientific Society of Medical Genetics, Poznan University of Medical Sciences, Poznan, Poland
| | - Marta Pawlak
- Department of Ophthalmology, Poznan University of Medical Sciences, Poznan, Poland
| | | | - Bartłomiej Kopaczewski
- Department of Neurosurgery, Karol Jonscher Clinical Hospital, Poznan University of Medical Sciences, Poznan, Poland
| | - Agnieszka Urzykowska
- Department of Nephrology, Kidney Transplantation and Hypertension, The Children's Memorial Health Institute, Warsaw, Poland
| | - Heleen H Arts
- Department of Pathology and Laboratory Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.,IWK Health Centre, Clinical Genomics Laboratory, Halifax, Nova Scotia, Canada
| | - Anna Gotz-Więckowska
- Department of Ophthalmology, Poznan University of Medical Sciences, Poznan, Poland
| | - Ryszard Grenda
- Department of Nephrology, Kidney Transplantation and Hypertension, The Children's Memorial Health Institute, Warsaw, Poland
| | - Anna Latos-Bieleńska
- Department of Medical Genetics, Poznan University of Medical Sciences, Poznan, Poland
| | - Renata Glazar
- Centers for Medical Genetics GENESIS, Poznan, Poland
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7
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Walczak-Sztulpa J, Wawrocka A, Doornbos C, van Beek R, Sowińska-Seidler A, Jamsheer A, Bukowska-Olech E, Latos-Bieleńska A, Grenda R, Bongers EMHF, Schmidts M, Obersztyn E, Krawczyński MR, Oud MM. Identical IFT140 Variants Cause Variable Skeletal Ciliopathy Phenotypes—Challenges for the Accurate Diagnosis. Front Genet 2022; 13:931822. [PMID: 35873489 PMCID: PMC9300986 DOI: 10.3389/fgene.2022.931822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 06/15/2022] [Indexed: 11/13/2022] Open
Abstract
Ciliopathies are rare congenital disorders, caused by defects in the cilium, that cover a broad clinical spectrum. A subgroup of ciliopathies showing significant phenotypic overlap are known as skeletal ciliopathies and include Jeune asphyxiating thoracic dysplasia (JATD), Mainzer-Saldino syndrome (MZSDS), cranioectodermal dysplasia (CED), and short-rib polydactyly (SRP). Ciliopathies are heterogeneous disorders with >187 associated genes, of which some genes are described to cause more than one ciliopathy phenotype. Both the clinical and molecular overlap make accurate diagnosing of these disorders challenging. We describe two unrelated Polish patients presenting with a skeletal ciliopathy who share the same compound heterozygous variants in IFT140 (NM_014,714.4) r.2765_2768del; p.(Tyr923Leufs*28) and exon 27–30 duplication; p.(Tyr1152_Thr1394dup). Apart from overlapping clinical symptoms the patients also show phenotypic differences; patient 1 showed more resemblance to a Mainzer-Saldino syndrome (MZSDS) phenotype, while patient 2 was more similar to the phenotype of cranioectodermal dysplasia (CED). In addition, functional testing in patient-derived fibroblasts revealed a distinct cilium phenotyps for each patient, and strikingly, the cilium phenotype of CED-like patient 2 resembled that of known CED patients. Besides two variants in IFT140, in depth exome analysis of ciliopathy associated genes revealed a likely-pathogenic heterozygous variant in INTU for patient 2 that possibly affects the same IFT-A complex to which IFT140 belongs and thereby could add to the phenotype of patient 2. Taken together, by combining genetic data, functional test results, and clinical findings we were able to accurately diagnose patient 1 with “IFT140-related ciliopathy with MZSDS-like features” and patient 2 with “IFT140-related ciliopathy with CED-like features”. This study emphasizes that identical variants in one ciliopathy associated gene can lead to a variable ciliopathy phenotype and that an in depth and integrated analysis of clinical, molecular and functional data is necessary to accurately diagnose ciliopathy patients.
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Affiliation(s)
| | - Anna Wawrocka
- Department of Medical Genetics, Poznan University of Medical Sciences, Poznan, Poland
| | - Cenna Doornbos
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands
| | - Ronald van Beek
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, Netherlands
| | - Anna Sowińska-Seidler
- Department of Medical Genetics, Poznan University of Medical Sciences, Poznan, Poland
| | - Aleksander Jamsheer
- Department of Medical Genetics, Poznan University of Medical Sciences, Poznan, Poland
- Centers for Medical Genetics, Poznan, Poland
| | | | - Anna Latos-Bieleńska
- Department of Medical Genetics, Poznan University of Medical Sciences, Poznan, Poland
| | - Ryszard Grenda
- Department of Nephrology, Kidney Transplantation and Hypertension, The Children’s Memorial Health Institute, Warsaw, Poland
| | | | - Miriam Schmidts
- Center for Pediatrics and Adolescent Medicine, University Hospital Freiburg, Freiburg University Faculty of Medicine, Freiburg, Germany
- CIBSS—Centre for Integrative Biological Signalling Studies, Freiburg University, Freiburg, Germany
| | - Ewa Obersztyn
- Department of Medical Genetics, Institute of Mother and Child, Warsaw, Poland
| | - Maciej R. Krawczyński
- Department of Medical Genetics, Poznan University of Medical Sciences, Poznan, Poland
- Centers for Medical Genetics, Poznan, Poland
| | - Machteld M. Oud
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, Netherlands
- *Correspondence: Machteld M. Oud,
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8
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Senum SR, Li Y(SM, Benson KA, Joli G, Olinger E, Lavu S, Madsen CD, Gregory AV, Neatu R, Kline TL, Audrézet MP, Outeda P, Nau CB, Meijer E, Ali H, Steinman TI, Mrug M, Phelan PJ, Watnick TJ, Peters DJ, Ong AC, Conlon PJ, Perrone RD, Cornec-Le Gall E, Hogan MC, Torres VE, Sayer JA, Harris PC, Harris PC. Monoallelic IFT140 pathogenic variants are an important cause of the autosomal dominant polycystic kidney-spectrum phenotype. Am J Hum Genet 2022; 109:136-156. [PMID: 34890546 DOI: 10.1016/j.ajhg.2021.11.016] [Citation(s) in RCA: 65] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 11/15/2021] [Indexed: 12/18/2022] Open
Abstract
Autosomal dominant polycystic kidney disease (ADPKD), characterized by progressive cyst formation/expansion, results in enlarged kidneys and often end stage kidney disease. ADPKD is genetically heterogeneous; PKD1 and PKD2 are the common loci (∼78% and ∼15% of families) and GANAB, DNAJB11, and ALG9 are minor genes. PKD is a ciliary-associated disease, a ciliopathy, and many syndromic ciliopathies have a PKD phenotype. In a multi-cohort/-site collaboration, we screened ADPKD-diagnosed families that were naive to genetic testing (n = 834) or for whom no PKD1 and PKD2 pathogenic variants had been identified (n = 381) with a PKD targeted next-generation sequencing panel (tNGS; n = 1,186) or whole-exome sequencing (WES; n = 29). We identified monoallelic IFT140 loss-of-function (LoF) variants in 12 multiplex families and 26 singletons (1.9% of naive families). IFT140 is a core component of the intraflagellar transport-complex A, responsible for retrograde ciliary trafficking and ciliary entry of membrane proteins; bi-allelic IFT140 variants cause the syndromic ciliopathy, short-rib thoracic dysplasia (SRTD9). The distinctive monoallelic phenotype is mild PKD with large cysts, limited kidney insufficiency, and few liver cysts. Analyses of the cystic kidney disease probands of Genomics England 100K showed that 2.1% had IFT140 LoF variants. Analysis of the UK Biobank cystic kidney disease group showed probands with IFT140 LoF variants as the third most common group, after PKD1 and PKD2. The proximity of IFT140 to PKD1 (∼0.5 Mb) in 16p13.3 can cause diagnostic confusion, and PKD1 variants could modify the IFT140 phenotype. Importantly, our studies link a ciliary structural protein to the ADPKD spectrum.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Peter C Harris
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN 55905, USA.
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9
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Ryżko J, Walczak-Sztulpa J, Czubkowski P, Latos-Bieleńska A, Kowalski A, Stefanowicz M, Jarmużek W, Grenda R, Pawłowska J. Case Report: Sequential Liver After Kidney Transplantation in a Patient With Sensenbrenner Syndrome (Cranioectodermal Dysplasia). Front Pediatr 2022; 10:834064. [PMID: 35281231 PMCID: PMC8914039 DOI: 10.3389/fped.2022.834064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 02/02/2022] [Indexed: 11/29/2022] Open
Abstract
Sensenbrenner syndrome, also known as cranioectodermal dysplasia (CED), is a rare ciliopathy clinically characterized by congenital craniofacial, skeletal, and ectodermal defects. Chronic kidney and liver insufficiency are also present in this disorder. Cranioectodermal dysplasia is an autosomal recessive and heterogeneous genetic disease. Six genes (IFT122, WDR35, IFT140, IFT43, IFT52, and WDR19) are known to be associated with this syndrome. Until 2021 more than 70 patients have been reported with CED, however, an orthotopic liver transplantation has been reported only in one case. Here, we present a case report of sequential liver-after-kidney transplantation in a male patient affected by CED. The kidney and liver transplantation was performed at the age of 7 and 12 years, respectively. Patients with Sensenbrenner syndrome require a multidisciplinary medical management and should regularly be followed-up by hepatologists and nephrologists, as the liver and kidney diseases are the major cause of morbidity and mortality.
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Affiliation(s)
- Joanna Ryżko
- Department of Gastroenterology, Hepatology, Nutritional Disorders and Pediatrics, The Children's Memorial Health Institute, Warsaw, Poland
| | | | - Piotr Czubkowski
- Department of Gastroenterology, Hepatology, Nutritional Disorders and Pediatrics, The Children's Memorial Health Institute, Warsaw, Poland
| | - Anna Latos-Bieleńska
- Department of Medical Genetics, Poznan University of Medical Sciences, Poznan, Poland
| | - Adam Kowalski
- Department of Pediatric Surgery and Organ Transplantation, The Children's Memorial Health Institute, Warsaw, Poland
| | - Marek Stefanowicz
- Department of Pediatric Surgery and Organ Transplantation, The Children's Memorial Health Institute, Warsaw, Poland
| | - Wioletta Jarmużek
- Department of Nephrology, Kidney Transplantation and Hypertension, The Children's Memorial Health Institute, Warsaw, Poland
| | - Ryszard Grenda
- Department of Nephrology, Kidney Transplantation and Hypertension, The Children's Memorial Health Institute, Warsaw, Poland
| | - Joanna Pawłowska
- Department of Gastroenterology, Hepatology, Nutritional Disorders and Pediatrics, The Children's Memorial Health Institute, Warsaw, Poland
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10
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Ciliary Signalling and Mechanotransduction in the Pathophysiology of Craniosynostosis. Genes (Basel) 2021; 12:genes12071073. [PMID: 34356089 PMCID: PMC8306115 DOI: 10.3390/genes12071073] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 07/10/2021] [Accepted: 07/13/2021] [Indexed: 12/25/2022] Open
Abstract
Craniosynostosis (CS) is the second most prevalent inborn craniofacial malformation; it results from the premature fusion of cranial sutures and leads to dimorphisms of variable severity. CS is clinically heterogeneous, as it can be either a sporadic isolated defect, more frequently, or part of a syndromic phenotype with mendelian inheritance. The genetic basis of CS is also extremely heterogeneous, with nearly a hundred genes associated so far, mostly mutated in syndromic forms. Several genes can be categorised within partially overlapping pathways, including those causing defects of the primary cilium. The primary cilium is a cellular antenna serving as a signalling hub implicated in mechanotransduction, housing key molecular signals expressed on the ciliary membrane and in the cilioplasm. This mechanical property mediated by the primary cilium may also represent a cue to understand the pathophysiology of non-syndromic CS. In this review, we aimed to highlight the implication of the primary cilium components and active signalling in CS pathophysiology, dissecting their biological functions in craniofacial development and in suture biomechanics. Through an in-depth revision of the literature and computational annotation of disease-associated genes we categorised 18 ciliary genes involved in CS aetiology. Interestingly, a prevalent implication of midline sutures is observed in CS ciliopathies, possibly explained by the specific neural crest origin of the frontal bone.
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11
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Yang Q, Zhang Q, Chen F, Yi S, Li M, Yi S, Xu X, Luo J. A novel combination of biallelic IFT122 variants associated with cranioectodermal dysplasia: A case report. Exp Ther Med 2021; 21:311. [PMID: 33717254 PMCID: PMC7885081 DOI: 10.3892/etm.2021.9742] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 01/13/2021] [Indexed: 12/17/2022] Open
Abstract
Cranioectodermal dysplasia (CED) or Sensenbrenner syndrome is a very rare autosomal-recessive disease that is characterized by craniofacial, skeletal and ectodermal abnormalities. The proteins encoded by six CED-associated genes are members of the intraflagelline transport (IFT) system, which serves an essential role in the assembly, maintenance and function of primary cilia. The current study identified compound novel heterozygous IFT122 (NM_052985.3) variants in a male Chinese infant with CED. The latter variant changes the length of the protein and may result in the partial loss-of-function of IFT122. With the simultaneous presence of frameshift and stop-loss variants, the patient manifested typical CED with fine and sparse hair, macrocephaly, dysmorphic facial features and upper limb phocomelia. A number of unusual phenotypic characteristics were additionally observed and included postaxial polydactyly of both hands and feet. The molecular confirmation of CED in this patient expands the CED-associated variant spectrum of IFT122 in CED, while the manifestation of CED in this patient provides additional clinical information regarding this syndrome. Moreover, the two variants identified in the proband provide a novel perspective into the phenotypes caused by different combinations of variants.
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Affiliation(s)
- Qi Yang
- Department of Genetic and Metabolic Central Laboratory, Guangxi Maternal and Child Health Hospital, Nanning, Guangxi 530023, P.R. China
| | - Qiang Zhang
- Department of Genetic and Metabolic Central Laboratory, Guangxi Maternal and Child Health Hospital, Nanning, Guangxi 530023, P.R. China
| | - Fei Chen
- Department of Genetic and Metabolic Central Laboratory, Guangxi Maternal and Child Health Hospital, Nanning, Guangxi 530023, P.R. China
| | - Shang Yi
- Department of Genetic and Metabolic Central Laboratory, Guangxi Maternal and Child Health Hospital, Nanning, Guangxi 530023, P.R. China
| | - Mengting Li
- Department of Genetic and Metabolic Central Laboratory, Guangxi Maternal and Child Health Hospital, Nanning, Guangxi 530023, P.R. China
| | - Sheng Yi
- Department of Genetic and Metabolic Central Laboratory, Guangxi Maternal and Child Health Hospital, Nanning, Guangxi 530023, P.R. China
| | - Xingmin Xu
- Department of Medical Genetics, Southern Medical University, Guangzhou, Guangdong 510800, P.R. China
| | - Jingsi Luo
- Department of Genetic and Metabolic Central Laboratory, Guangxi Maternal and Child Health Hospital, Nanning, Guangxi 530023, P.R. China
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12
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Walczak-Sztulpa J, Posmyk R, Bukowska-Olech EM, Wawrocka A, Jamsheer A, Oud MM, Schmidts M, Arts HH, Latos-Bielenska A, Wasilewska A. Compound heterozygous IFT140 variants in two Polish families with Sensenbrenner syndrome and early onset end-stage renal disease. Orphanet J Rare Dis 2020; 15:36. [PMID: 32007091 PMCID: PMC6995138 DOI: 10.1186/s13023-020-1303-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 01/13/2020] [Indexed: 02/04/2023] Open
Abstract
Background Sensenbrenner syndrome, which is also known as cranioectodermal dysplasia (CED), is a rare, autosomal recessive ciliary chondrodysplasia characterized by a variety of clinical features including a distinctive craniofacial appearance as well as skeletal, ectodermal, liver and renal anomalies. Progressive renal disease can be life-threatening in this condition. CED is a genetically heterogeneous disorder. Currently, variants in any of six genes (IFT122, WDR35, IFT140, IFT43, IFT52 and WDR19) have been associated with this syndrome. All of these genes encode proteins essential for intraflagellar transport (IFT) a process that is required for cilium assembly, maintenance and function. Intra- and interfamilial clinical variability has been reported in CED, which is consistent with CED’s genetic heterogeneity and is indicative of genetic background effects. Results Two male CED patients from two unrelated Polish families were included in this study. Clinical assessment revealed distinctive clinical features of Sensenbrenner syndrome, such as dolichocephaly, shortening of long bones and early onset renal failure. Ectodermal anomalies also included thin hair, short and thin nails, and small teeth in both patients. Next generation sequencing (NGS) techniques were performed in order to determine the underlying genetic cause of the disorder using whole exome sequencing (WES) for patient 1 and a custom NGS-based panel for patient 2. Subsequent qPCR and duplex PCR analysis were conducted for both patients. Genetic analyses identified compound heterozygous variants in the IFT140 gene in both affected individuals. Both patients harbored a tandem duplication variant p.Tyr1152_Thr1394dup on one allele. In addition, a novel missense variant, p.(Leu109Pro), and a previously described p.(Gly522Glu) variant were identified in the second allele in patients 1 and 2, respectively. Segregation analysis of the variants was consistent with the expected autosomal recessive disease inheritance pattern. Both patients had severe renal failure requiring kidney transplantation in early childhood. Conclusion The finding of compound heterozygous IFT140 mutations in two unrelated CED patients provide further evidence that IFT140 gene mutations are associated with this syndrome. Our studies confirm that IFT140 changes in patients with CED are associated with early onset end-stage renal disease. Moreover, this report expands our knowledge of the clinical- and molecular genetics of Sensenbrenner syndrome and it highlights the importance of multidisciplinary approaches in the care of CED patients.
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Affiliation(s)
- Joanna Walczak-Sztulpa
- Department of Medical Genetics, Poznan University of Medical Sciences, Rokietnicka 8 Street, 60-608, Poznan, Poland.
| | - Renata Posmyk
- Department of Perinatology, Medical University of Bialystok, Bialystok, Poland
| | - Ewelina M Bukowska-Olech
- Department of Medical Genetics, Poznan University of Medical Sciences, Rokietnicka 8 Street, 60-608, Poznan, Poland
| | - Anna Wawrocka
- Department of Medical Genetics, Poznan University of Medical Sciences, Rokietnicka 8 Street, 60-608, Poznan, Poland
| | - Aleksander Jamsheer
- Department of Medical Genetics, Poznan University of Medical Sciences, Rokietnicka 8 Street, 60-608, Poznan, Poland
| | - Machteld M Oud
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Miriam Schmidts
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Center for Pediatrics and Adolescent Medicine, Freiburg University Hospital, Freiburg University Faculty of Medicine, Freiburg, Germany
| | - Heleen H Arts
- Department of Pathology and Laboratory Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.,IWK Health Centre, Clinical Genomics Laboratory, Halifax, Nova Scotia, Canada
| | - Anna Latos-Bielenska
- Department of Medical Genetics, Poznan University of Medical Sciences, Rokietnicka 8 Street, 60-608, Poznan, Poland
| | - Anna Wasilewska
- Department of Pediatrics and Nephrology, Medical University of Bialystok, Bialystok, Poland
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Zhang Y, Liu H, Li W, Zhang Z, Zhang S, Teves ME, Stevens C, Foster JA, Campbell GE, Windle JJ, Hess RA, Pazour GJ, Zhang Z. Intraflagellar transporter protein 140 (IFT140), a component of IFT-A complex, is essential for male fertility and spermiogenesis in mice. Cytoskeleton (Hoboken) 2018; 75:70-84. [PMID: 29236364 DOI: 10.1002/cm.21427] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 11/16/2017] [Accepted: 11/20/2017] [Indexed: 11/11/2022]
Abstract
Intraflagellar transport (IFT) is a conserved mechanism essential for the assembly and maintenance of most eukaryotic cilia and flagella. However, little is known about its role in sperm flagella formation and male fertility. IFT140 is a component of IFT-A complex. In mouse, it is highly expressed in the testis. Ift140 gene was inactivated specifically in mouse spermatocytes/spermatids. The mutant mice did not show any gross abnormalities, but all were infertile and associated with significantly reduced sperm number and motility. Multiple sperm morphological abnormalities were discovered, including amorphous heads, short/bent flagella and swollen tail tips, as well as vesicles along the flagella due to spermiogenesis defects. The epididymides contained round bodies of cytoplasm derived from the sloughing of the cytoplasmic lobes and residual bodies. Knockout of Ift140 did not significantly affect testicular expression levels of selective IFT components but localization of IFT27 and IFT88, two components of IFT-B complex, was changed. Our findings demonstrate that IFT140 is a key regulator for male fertility and normal spermiogenesis in mice. It not only plays a role in sperm flagella assembling, but is also involved in critical assembly of proteins that interface between the germ cell plasma and the Sertoli cell.
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Affiliation(s)
- Yong Zhang
- Department of Dermatology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.,Department of Obstetrics & Gynecology, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Hong Liu
- Department of Obstetrics & Gynecology, Virginia Commonwealth University, Richmond, Virginia 23298.,School of Public Health, Wuhan University of Science and Technology, Wuhan 430060, Hubei
| | - Wei Li
- Department of Obstetrics & Gynecology, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Zhengang Zhang
- Department of Obstetrics & Gynecology, Virginia Commonwealth University, Richmond, Virginia 23298.,Department of Gastroenterology, Tongji Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei
| | - Shiyang Zhang
- Department of Obstetrics & Gynecology, Virginia Commonwealth University, Richmond, Virginia 23298.,School of Public Health, Wuhan University of Science and Technology, Wuhan 430060, Hubei
| | - Maria E Teves
- Department of Obstetrics & Gynecology, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Courtney Stevens
- Department of Biology, Randolph-Macon College, Ashland, Virginia 23005
| | - James A Foster
- Department of Biology, Randolph-Macon College, Ashland, Virginia 23005
| | - Gregory E Campbell
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Jolene J Windle
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia 23298
| | - Rex A Hess
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois, 2001 S. Lincoln, Urbana, Illinois 61802-6199
| | - Gregory J Pazour
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Zhibing Zhang
- Department of Obstetrics & Gynecology, Virginia Commonwealth University, Richmond, Virginia 23298.,School of Public Health, Wuhan University of Science and Technology, Wuhan 430060, Hubei
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14
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Li G, Liu M, Zhang S, Wan H, Zhang Q, Yue R, Yan X, Wang X, Wang Z, Sun Y. Essential Role of IFT140 in Promoting Dentinogenesis. J Dent Res 2017; 97:423-431. [PMID: 29195058 DOI: 10.1177/0022034517741283] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Primary cilia, with highly regulated cellular sensory functions, play key roles in tissue development and function maintenance. Intraflagellar transport 140 (IFT140) is a subunit of IFT complex A, which is specialized for retrograde transportation in cilia. Mutations of Ift140 are usually associated with syndromic ciliopathy and may cause isolated diseases such as retinal dystrophy, short ribs, and polycystic kidney. However, the role of IFT140 in tooth development has not been well investigated. In this study, a close relationship between IFT140 and dentin formation is disclosed. During tooth development, IFT140 was highly expressed in odontoblasts. To further understand the role of IFT140 in dentinogenesis, Ift140flox/flox/Osx-Cre mouse was generated. The dentin thickness of Ift140flox/flox/Osx-Cre mouse is thinner and the dentin formation is slower than that in control. In vitro, deletion of IFT140 in odontoblasts led to poor odontogenic differentiation, abnormal primary cilia, and decreased Sonic hedgehog signaling molecules. More important, due to loss of primary cilia in odontoblasts by IFT140 deletion, reparative dentin formation was impaired in a tooth-drilling model. These results suggest that cilia gene IFT140 is essential in promoting dentin formation and reparation.
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Affiliation(s)
- G Li
- 1 Department of Implantology, School & Hospital of Stomatology, Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai, China
| | - M Liu
- 2 Department of Endodontics, School & Hospital of Stomatology, Tongji University, Shanghai, China
| | - S Zhang
- 1 Department of Implantology, School & Hospital of Stomatology, Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai, China
| | - H Wan
- 1 Department of Implantology, School & Hospital of Stomatology, Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai, China
| | - Q Zhang
- 2 Department of Endodontics, School & Hospital of Stomatology, Tongji University, Shanghai, China
| | - R Yue
- 3 School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - X Yan
- 4 State Key Laboratory of Cell Biology, CAS Centre for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - X Wang
- 5 Department of Cell Biology & Institute of Biomedicine, College of Life Science and Technology, Jinan University, Guangzhou, China
| | - Z Wang
- 1 Department of Implantology, School & Hospital of Stomatology, Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai, China
| | - Y Sun
- 1 Department of Implantology, School & Hospital of Stomatology, Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai, China
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Walczak-Sztulpa J, Wawrocka A, Swiader-Lesniak A, Socha M, Jamsheer A, Drozdz D, Latos-Bielenska A, Zachwieja K. Clinical and molecular genetic characterization of a male patient with Sensenbrenner syndrome (cranioectodermal dysplasia) and biallelicWDR35mutations. Birth Defects Res 2017; 110:376-381. [DOI: 10.1002/bdr2.1151] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 10/01/2017] [Accepted: 10/10/2017] [Indexed: 12/16/2022]
Affiliation(s)
| | - Anna Wawrocka
- Department of Medical Genetics; Poznan University of Medical Sciences; Poznan Poland
| | - Anna Swiader-Lesniak
- Department of Anthropology; The Children's Memorial Health Institute; Warsaw Poland
| | - Magdalena Socha
- Department of Medical Genetics; Poznan University of Medical Sciences; Poznan Poland
| | - Aleksander Jamsheer
- Department of Medical Genetics; Poznan University of Medical Sciences; Poznan Poland
| | - Dorota Drozdz
- Department of Pediatric Nephrology and Hypertension, Faculty of Medicine; Jagiellonian University Medical College; Cracow Poland
| | - Anna Latos-Bielenska
- Department of Medical Genetics; Poznan University of Medical Sciences; Poznan Poland
| | - Katarzyna Zachwieja
- Department of Pediatric Nephrology and Hypertension, Faculty of Medicine; Jagiellonian University Medical College; Cracow Poland
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Helm BM, Willer JR, Sadeghpour A, Golzio C, Crouch E, Vergano SS, Katsanis N, Davis EE. Partial uniparental isodisomy of chromosome 16 unmasks a deleterious biallelic mutation in IFT140 that causes Mainzer-Saldino syndrome. Hum Genomics 2017; 11:16. [PMID: 28724397 PMCID: PMC5517791 DOI: 10.1186/s40246-017-0111-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 06/29/2017] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND The ciliopathies represent an umbrella group of >50 clinical entities that share both clinical features and molecular etiology underscored by structural and functional defects of the primary cilium. Despite the advances in gene discovery, this group of entities continues to pose a diagnostic challenge, in part due to significant genetic and phenotypic heterogeneity and variability. We consulted a pediatric case from asymptomatic, non-consanguineous parents who presented as a suspected ciliopathy due to a constellation of retinal, renal, and skeletal findings. RESULTS Although clinical panel sequencing of genes implicated in nephrotic syndromes yielded no likely causal mutation, an oligo-SNP microarray identified a ~20-Mb region of homozygosity, with no altered gene dosage, on chromosome 16p13. Intersection of the proband's phenotypes with known disease genes within the homozygous region yielded a single candidate, IFT140, encoding a retrograde intraflagellar transport protein implicated previously in several ciliopathies, including the phenotypically overlapping Mainzer-Saldino syndrome (MZSDS). Sanger sequencing yielded a maternally inherited homozygous c.634G>A; p.Gly212Arg mutation altering the exon 6 splice donor site. Functional studies in cells from the proband showed that the locus produced two transcripts: a majority message containing a mis-splicing event that caused a premature termination codon and a minority message homozygous for the p.Gly212Arg allele. Zebrafish in vivo complementation studies of the latter transcript demonstrated a loss of function effect. Finally, we conducted post-hoc trio-based whole exome sequencing studies to (a) test the possibility of other causal loci in the proband and (b) explain the Mendelian error of segregation for the IFT140 mutation. We show that the proband harbors a chromosome 16 maternal heterodisomy, with segmental isodisomy at 16p13, likely due to a meiosis I error in the maternal gamete. CONCLUSIONS Using clinical phenotyping combined with research-based genetic and functional studies, we have characterized a recurrent IFT140 mutation in the proband; together, these data are consistent with MZSDS. Additionally, we report a rare instance of a uniparental isodisomy unmasking a deleterious mutation to cause a ciliary disorder.
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Affiliation(s)
- Benjamin M Helm
- Division of Medical Genetics and Metabolism, Children's Hospital of The King's Daughters, Norfolk, VA, 23507, USA.,Department of Medical & Molecular Genetics, Riley Hospital for Children at IU Health, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Jason R Willer
- Center for Human Disease Modeling, Duke University Medical Center, Durham, NC, 27701, USA
| | - Azita Sadeghpour
- Center for Human Disease Modeling, Duke University Medical Center, Durham, NC, 27701, USA
| | - Christelle Golzio
- Center for Human Disease Modeling, Duke University Medical Center, Durham, NC, 27701, USA.,Institute of Genetics and Molecular and Cellular Biology, 67404, Illkirch, France
| | - Eric Crouch
- Department of Ophthalmology, Children's Hospital of the King's Daughters, Norfolk, VA, 23507, USA
| | - Samantha Schrier Vergano
- Division of Medical Genetics and Metabolism, Children's Hospital of The King's Daughters, Norfolk, VA, 23507, USA.,Department of Pediatrics, Eastern Virginia Medical School, Norfolk, VA, 23507, USA
| | - Nicholas Katsanis
- Center for Human Disease Modeling, Duke University Medical Center, Durham, NC, 27701, USA.
| | - Erica E Davis
- Center for Human Disease Modeling, Duke University Medical Center, Durham, NC, 27701, USA.
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