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Jaron R, Rosenfeld N, Zahdeh F, Carmi S, Beni-Adani L, Doviner V, Picard E, Segel R, Zeligson S, Carmel L, Renbaum P, Levy-Lahad E. Expanding the phenotype of CRB2 mutations - A new ciliopathy syndrome? Clin Genet 2016; 90:540-544. [PMID: 26925547 DOI: 10.1111/cge.12764] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 02/09/2016] [Accepted: 02/22/2016] [Indexed: 12/21/2022]
Abstract
Recessive CRB2 mutations were recently reported to cause both steroid resistant nephrotic syndrome and prenatal onset ventriculomegaly with kidney disease. We report two Ashkenazi Jewish siblings clinically diagnosed with ciliopathy. Both presented with severe congenital hydrocephalus and mild urinary tract anomalies. One affected sibling also has lung hypoplasia and heart defects. Exome sequencing and further CRB2 analysis revealed that both siblings are compound heterozygotes for CRB2 mutations p.N800K and p.Gly1036Alafs*43, and heterozygous for a deleterious splice variant in the ciliopathy gene TTCB21. CRB2 is a polarity protein which plays a role in ciliogenesis and ciliary function. Biallelic CRB2 mutations in animal models result in phenotypes consistent with ciliopathy. This report expands the phenotype of CRB2 mutations to include lung hypoplasia and uretero-pelvic renal anomalies, and confirms cardiac malformation as a feature. We suggest that CRB2-associated disease is a new ciliopathy syndrome with possible digenic/triallelic inheritance, as observed in other ciliopathies. Clinically, CRB2 should be assessed when ciliopathy is suspected, especially in Ashkenazi Jews, where we found that p.N800K carrier frequency is 1 of 64. Patients harboring CRB2 mutations should be tested for the complete range of ciliopathy manifestations.
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Goncalves S, Goldstein BJ. Pathophysiology of Olfactory Disorders and Potential Treatment Strategies. CURRENT OTORHINOLARYNGOLOGY REPORTS 2016; 4:115-121. [PMID: 27529054 DOI: 10.1007/s40136-016-0113-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Olfactory disorders have been regarded in the past with a sense of therapeutic nihilism. However, there have been remarkable advances in chemosensory research over the past several years. The clinical importance of olfactory disorders is well established, and entities such as presbyosmia have gained considerable broad attention. Powerful basic science experimental approaches have revealed aspects of olfactory neuron physiology, olfactory tissue maintenance and regeneration that provide new potential therapeutic targets for certain forms of olfactory dysfunction. Although many recent advances remain in pre-clinical stages, there is considerable reason for optimism regarding future approaches for treatment of patients with olfactory loss.
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Szmigielska A, Krzemień G, Roszkowska-Blaim M, Obersztyn E. Polydactyly and obesity - the clinical manifestation of ciliopathy: a boy with Bardet-Biedl syndrome. DEVELOPMENTAL PERIOD MEDICINE 2016; 20:105-109. [PMID: 27442694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
UNLABELLED The prevalence of obesity in children is still rising all over the world. The most common reason for significant weight gain is a high-calorie diet and decreased physical activity. However, apart from environmental factors, genetic predisposition plays a crucial role in the pathomechanism of obesity. We present the case of a boy with pathological obesity and Bardet-Biedl syndrome (BBS). BBS is a ciliopathy, a heterogeneous group of rare disorders associated with defects in primary cilia. Other clinical signs and symptoms of BBS are: polydactyly, hypertension, hyperlipidemia, hypogonadotrophic hypogonadism, intellectual disability, rod-cone dystrophy, genitourinary and renal abnormalities. CONCLUSIONS genetic factors of rapid weight gain should be taken into consideration in a child with obesity. Polydactyly can be associated with ciliopathy. A patient with Bardet-Biedl syndrome requires multi-specialist care.
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Liu YP, Bosch DGM, Siemiatkowska AM, Rendtorff ND, Boonstra FN, Möller C, Tranebjærg L, Katsanis N, Cremers FPM. Putative digenic inheritance of heterozygous RP1L1 and C2orf71 null mutations in syndromic retinal dystrophy. Ophthalmic Genet 2016; 38:127-132. [PMID: 27029556 DOI: 10.3109/13816810.2016.1151898] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Retinitis pigmentosa (RP) is the most common cause of inherited retinal degeneration and can occur in non-syndromic and syndromic forms. Syndromic RP is accompanied by other symptoms such as intellectual disability, hearing loss, or congenital abnormalities. Both forms are known to exhibit complex genetic interactions that can modulate the penetrance and expressivity of the phenotype. MATERIALS AND METHODS In an individual with atypical RP, hearing loss, ataxia and cerebellar atrophy, whole exome sequencing was performed. The candidate pathogenic variants were tested by developing an in vivo zebrafish model and assaying for retinal and cerebellar integrity. RESULTS Exome sequencing revealed a complex heterozygous protein-truncating mutation in RP1L1, p.[(Lys111Glnfs*27; Gln2373*)], and a heterozygous nonsense mutation in C2orf71, p.(Ser512*). Mutations in both genes have previously been implicated in autosomal recessive non-syndromic RP, raising the possibility of a digenic model in this family. Functional testing in a zebrafish model for two key phenotypes of the affected person showed that the combinatorial suppression of rp1l1 and c2orf71l induced discrete pathology in terms of reduction of eye size with concomitant loss of rhodopsin in the photoreceptors, and disorganization of the cerebellum. CONCLUSIONS We propose that the combination of heterozygous loss-of-function mutations in these genes drives syndromic retinal dystrophy, likely through the genetic interaction of at least two loci. Haploinsufficiency at each of these loci is insufficient to induce overt pathology.
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Girisha KM, Shukla A, Trujillano D, Bhavani GS, Hebbar M, Kadavigere R, Rolfs A. A homozygous nonsense variant in IFT52 is associated with a human skeletal ciliopathy. Clin Genet 2016; 90:536-539. [PMID: 26880018 DOI: 10.1111/cge.12762] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 02/12/2016] [Accepted: 02/12/2016] [Indexed: 11/30/2022]
Abstract
Intraflagellar transport (IFT) is vital for the functioning of primary cilia. Defects in several components of IFT complexes cause a spectrum of ciliopathies with variable involvement of skeleton, brain, eyes, ectoderm and kidneys. We examined a child from a consanguineous family who had short stature, narrow thorax, short hands and feet, postaxial polydactyly of hands, pigmentary retinopathy, small teeth and skeletal dysplasia. The clinical phenotype of the child shows significant overlap with cranioectodermal dysplasia type I (Sensenbrenner syndrome). Whole-exome sequencing revealed a homozygous nonsense variant p.R142* in IFT52 encoding an IFT-B core complex protein as the probable cause of her condition. This is the first report of a human disease associated with IFT52.
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Loo CKC, Pereira TN, Ramsing M, Vogel I, Petersen OB, Ramm GA. Mechanism of pancreatic and liver malformations in human fetuses with short-rib polydactyly syndrome. ACTA ACUST UNITED AC 2016; 106:549-62. [PMID: 26970085 DOI: 10.1002/bdra.23495] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 02/09/2016] [Accepted: 02/11/2016] [Indexed: 12/29/2022]
Abstract
BACKGROUND The short-rib polydactyly (SRP) syndromes are rare skeletal dysplasias caused by abnormalities in primary cilia, sometimes associated with visceral malformations. METHODS The pathogenesis of ductal plate malformation (DPM) varies in different syndromes and has not been investigated in SRP. We have studied liver development in five SRP fetuses and pancreatic development in one SRP fetus, with genetically confirmed mutations in cilia related genes, with and without DPMs, using the immunoperoxidase technique, and compared these to other syndromes with DPM. RESULTS Acetylated tubulin expression was abnormal in DPM in SRP, Meckel syndrome, and autosomal recessive polycystic kidney disease (ARPKD), confirming ciliary anomalies. SDF-1 was abnormally expressed in SRP and two of three cases of autosomal dominant polycystic kidney disease (ADPKD) but not ARPKD or Meckel. Increased density of quiescent hepatic stellate cells was seen in SRP, Meckel, one of three cases of ARPKD, and two of three cases of ADPKD with aberrant hepatocyte expression of keratin 19 in SRP and ADPKD. Immunophenotypic abnormalities were present even in fetal liver without fully developed DPMs. The SRP case with DPM and pancreatic malformations showed abnormalities in the pancreatic head (influenced by mesenchyme from the septum transversum, similar to liver) but not pancreatic body (influenced by mesenchyme adjacent to the notochord). CONCLUSION In SRP, there are differentiation defects of hepatocytes, cholangiocytes, and liver mesenchyme and, in rare cases, pancreatic mesenchymal anomalies. The morphological changes were subtle in early gestation but immunophenotypic abnormalities were present. Mesenchymal-epithelial interactions may contribute to the malformations. Birth Defects Research (Part A) 106:549-562, 2016. © 2016 Wiley Periodicals, Inc.
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Terré B, Piergiovanni G, Segura-Bayona S, Gil-Gómez G, Youssef SA, Attolini CSO, Wilsch-Bräuninger M, Jung C, Rojas AM, Marjanović M, Knobel PA, Palenzuela L, López-Rovira T, Forrow S, Huttner WB, Valverde MA, de Bruin A, Costanzo V, Stracker TH. GEMC1 is a critical regulator of multiciliated cell differentiation. EMBO J 2016; 35:942-60. [PMID: 26933123 DOI: 10.15252/embj.201592821] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 02/05/2016] [Indexed: 11/09/2022] Open
Abstract
The generation of multiciliated cells (MCCs) is required for the proper function of many tissues, including the respiratory tract, brain, and germline. Defects in MCC development have been demonstrated to cause a subclass of mucociliary clearance disorders termed reduced generation of multiple motile cilia (RGMC). To date, only two genes, Multicilin (MCIDAS) and cyclin O (CCNO) have been identified in this disorder in humans. Here, we describe mice lacking GEMC1 (GMNC), a protein with a similar domain organization as Multicilin that has been implicated in DNA replication control. We have found that GEMC1-deficient mice are growth impaired, develop hydrocephaly with a high penetrance, and are infertile, due to defects in the formation of MCCs in the brain, respiratory tract, and germline. Our data demonstrate that GEMC1 is a critical regulator of MCC differentiation and a candidate gene for human RGMC or related disorders.
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Jaffe KM, Grimes DT, Schottenfeld-Roames J, Werner ME, Ku TSJ, Kim SK, Pelliccia JL, Morante NFC, Mitchell BJ, Burdine RD. c21orf59/kurly Controls Both Cilia Motility and Polarization. Cell Rep 2016; 14:1841-9. [PMID: 26904945 DOI: 10.1016/j.celrep.2016.01.069] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 11/29/2015] [Accepted: 01/22/2016] [Indexed: 11/17/2022] Open
Abstract
Cilia are microtubule-based projections that function in the movement of extracellular fluid. This requires cilia to be: (1) motile and driven by dynein complexes and (2) correctly polarized on the surface of cells, which requires planar cell polarity (PCP). Few factors that regulate both processes have been discovered. We reveal that C21orf59/Kurly (Kur), a cytoplasmic protein with some enrichment at the base of cilia, is needed for motility; zebrafish mutants exhibit characteristic developmental abnormalities and dynein arm defects. kur was also required for proper cilia polarization in the zebrafish kidney and the larval skin of Xenopus laevis. CRISPR/Cas9 coupled with homologous recombination to disrupt the endogenous kur locus in Xenopus resulted in the asymmetric localization of the PCP protein Prickle2 being lost in mutant multiciliated cells. Kur also makes interactions with other PCP components, including Disheveled. This supports a model wherein Kur plays a dual role in cilia motility and polarization.
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Filges I, Bruder E, Brandal K, Meier S, Undlien DE, Waage TR, Hoesli I, Schubach M, de Beer T, Sheng Y, Hoeller S, Schulzke S, Røsby O, Miny P, Tercanli S, Oppedal T, Meyer P, Selmer KK, Strømme P. Strømme Syndrome Is a Ciliary Disorder Caused by Mutations in CENPF. Hum Mutat 2016; 37:359-63. [PMID: 26820108 DOI: 10.1002/humu.22960] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 01/08/2016] [Indexed: 11/10/2022]
Abstract
Strømme syndrome was first described by Strømme et al. (1993) in siblings presenting with "apple peel" type intestinal atresia, ocular anomalies and microcephaly. The etiology remains unknown to date. We describe the long-term clinical follow-up data for the original pair of siblings as well as two previously unreported siblings with a severe phenotype overlapping that of the Strømme syndrome including fetal autopsy results. Using family-based whole-exome sequencing, we identified truncating mutations in the centrosome gene CENPF in the two nonconsanguineous Caucasian sibling pairs. Compound heterozygous inheritance was confirmed in both families. Recently, mutations in this gene were shown to cause a fetal lethal phenotype, the phenotype and functional data being compatible with a human ciliopathy [Waters et al., 2015]. We show for the first time that Strømme syndrome is an autosomal-recessive disease caused by mutations in CENPF that can result in a wide phenotypic spectrum.
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Shamseldin H, Alazami A, Manning M, Hashem A, Caluseiu O, Tabarki B, Esplin E, Schelley S, Innes A, Parboosingh J, Lamont R, Majewski J, Bernier F, Alkuraya F, Alkuraya FS. RTTN Mutations Cause Primary Microcephaly and Primordial Dwarfism in Humans. Am J Hum Genet 2015; 97:862-8. [PMID: 26608784 DOI: 10.1016/j.ajhg.2015.10.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2015] [Accepted: 10/20/2015] [Indexed: 10/22/2022] Open
Abstract
Primary microcephaly is a developmental brain anomaly that results from defective proliferation of neuroprogenitors in the germinal periventricular zone. More than a dozen genes are known to be mutated in autosomal-recessive primary microcephaly in isolation or in association with a more generalized growth deficiency (microcephalic primordial dwarfism), but the genetic heterogeneity is probably more extensive. In a research protocol involving autozygome mapping and exome sequencing, we recruited a multiplex consanguineous family who is affected by severe microcephalic primordial dwarfism and tested negative on clinical exome sequencing. Two candidate autozygous intervals were identified, and the second round of exome sequencing revealed a single intronic variant therein (c.2885+8A>G [p.Ser963(∗)] in RTTN exon 23). RT-PCR confirmed that this change creates a cryptic splice donor and thus causes retention of the intervening 7 bp of the intron and leads to premature truncation. On the basis of this finding, we reanalyzed the exome file of a second consanguineous family affected by a similar phenotype and identified another homozygous change in RTTN as the likely causal mutation. Combined linkage analysis of the two families confirmed that RTTN maps to the only significant linkage peak. Finally, through international collaboration, a Canadian multiplex family affected by microcephalic primordial dwarfism and biallelic mutation of RTTN was identified. Our results expand the phenotype of RTTN-related disorders, hitherto limited to polymicrogyria, to include microcephalic primordial dwarfism with a complex brain phenotype involving simplified gyration.
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Yu F, Ran J, Zhou J. Ciliopathies: Does HDAC6 Represent a New Therapeutic Target? Trends Pharmacol Sci 2015; 37:114-119. [PMID: 26651415 DOI: 10.1016/j.tips.2015.11.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 10/28/2015] [Accepted: 11/02/2015] [Indexed: 02/02/2023]
Abstract
Cilia are cellular appendages with critical roles in sensing and transducing environmental signals and guiding fluid flow. Consistent with these diverse activities, defects in ciliary structure or function have been implicated in a variety of human diseases, collectively known as 'ciliopathies'. Histone deacetylase 6 (HDAC6) is a unique cytoplasmic enzyme that regulates many biological processes through its deacetylase and ubiquitin-binding activities. There is accumulating evidence that HDAC6 is a major driver of ciliary disassembly. Small-molecule compounds that inhibit HDAC6 have been demonstrated to restore ciliary structure and function in several different ciliopathies. Here, we discuss recent findings that highlight the important role for HDAC6 in mediating ciliary disassembly and the potential for HDAC6-selective inhibitors as therapeutics for specific ciliopathies.
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Shylo NA, Christopher KJ, Iglesias A, Daluiski A, Weatherbee SD. TMEM107 Is a Critical Regulator of Ciliary Protein Composition and Is Mutated in Orofaciodigital Syndrome. Hum Mutat 2015; 37:155-9. [PMID: 26518474 DOI: 10.1002/humu.22925] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 10/14/2015] [Indexed: 12/31/2022]
Abstract
The proximate causes of multiple human genetic syndromes (ciliopathies) are disruptions in the formation or function of the cilium, an organelle required for a multitude of developmental processes. We previously identified Tmem107 as a critical regulator of cilia formation and embryonic organ development in the mouse. Here, we describe a patient with a mutation in TMEM107 that developed atypical Orofaciodigital syndrome (OFD), and show that the OFD patient shares several morphological features with the Tmem107 mutant mouse including polydactyly and reduced numbers of ciliated cells. We show that TMEM107 appears to function within cilia to regulate protein content, as key ciliary proteins do not localize normally in cilia derived from the Tmem107 mouse mutant and the human patient. These data indicate that TMEM107 plays a key, conserved role in regulating ciliary protein composition, and is a novel candidate for ciliopathies of unknown etiology.
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Frölander HE, Möller C, Rudner M, Mishra S, Marshall JD, Piacentini H, Lyxell B. Theory-of-mind in individuals with Alström syndrome is related to executive functions, and verbal ability. Front Psychol 2015; 6:1426. [PMID: 26441796 PMCID: PMC4585138 DOI: 10.3389/fpsyg.2015.01426] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 09/07/2015] [Indexed: 02/03/2023] Open
Abstract
Objective: This study focuses on cognitive prerequisites for the development of theory-of-mind (ToM), the ability to impute mental states to self and others in young adults with Alström syndrome (AS). AS is a rare and quite recently described recessively inherited ciliopathic disorder which causes progressive sensorineural hearing loss and juvenile blindness, as well as many other organ dysfunctions. Two cognitive abilities were considered; Phonological working memory (WM) and executive functions (EF), both of importance in speech development. Methods: Ten individuals (18–37 years) diagnosed with AS, and 20 individuals with no known impairment matched for age, gender, and educational level participated. Sensory functions were measured. Information about motor functions and communicative skills was obtained from responses to a questionnaire. ToM was assessed using Happés strange stories, verbal ability by a vocabulary test, phonological WM by means of an auditory presented non-word serial recall task and EF by tests of updating and inhibition. Results: The AS group performed at a significantly lower level than the control group in both the ToM task and the EF tasks. A significant correlation was observed between recall of non-words and EF in the AS group. Updating, but not inhibition, correlated significantly with verbal ability, whereas both updating and inhibition were significantly related to the ability to initiate and sustain communication. Poorer performance in the ToM and EF tasks were related to language perseverance and motor mannerisms. Conclusion: The AS group displayed a delayed ToM as well as reduced phonological WM, EF, and verbal ability. A significant association between ToM and EF, suggests a compensatory role of EF. This association may reflect the importance of EF to perceive and process input from the social environment when the social interaction is challenged by dual sensory loss. We argue that limitations in EF capacity in individuals with AS, to some extent, may be related to early blindness and progressive hearing loss, but maybe also to gene specific abnormalities.
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Stephen LA, Tawamie H, Davis GM, Tebbe L, Nürnberg P, Nürnberg G, Thiele H, Thoenes M, Boltshauser E, Uebe S, Rompel O, Reis A, Ekici AB, McTeir L, Fraser AM, Hall EA, Mill P, Daudet N, Cross C, Wolfrum U, Jamra RA, Davey MG, Bolz HJ. TALPID3 controls centrosome and cell polarity and the human ortholog KIAA0586 is mutated in Joubert syndrome (JBTS23). eLife 2015; 4. [PMID: 26386247 PMCID: PMC4641851 DOI: 10.7554/elife.08077] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 09/19/2015] [Indexed: 12/30/2022] Open
Abstract
Joubert syndrome (JBTS) is a severe recessive neurodevelopmental ciliopathy which can affect several organ systems. Mutations in known JBTS genes account for approximately half of the cases. By homozygosity mapping and whole-exome sequencing, we identified a novel locus, JBTS23, with a homozygous splice site mutation in KIAA0586 (alias TALPID3), a known lethal ciliopathy locus in model organisms. Truncating KIAA0586 mutations were identified in two additional patients with JBTS. One mutation, c.428delG (p.Arg143Lysfs*4), is unexpectedly common in the general population and may be a major contributor to JBTS. We demonstrate KIAA0586 protein localization at the basal body in human and mouse photoreceptors, as is common for JBTS proteins, and also in pericentriolar locations. We show that loss of TALPID3 (KIAA0586) function in animal models causes abnormal tissue polarity, centrosome length and orientation, and centriolar satellites. We propose that JBTS and other ciliopathies may in part result from cell polarity defects. DOI:http://dx.doi.org/10.7554/eLife.08077.001 Joubert syndrome is a rare and severe neurodevelopmental disease in which two parts of the brain called the cerebellar vermis and brainstem do not develop properly. The disease is caused by defects in the formation of small projections from the surface of cells, called cilia, which are essential for signalling processes inside cells. Mutations in at least 25 genes are known to cause Joubert syndrome, and all encode proteins that create or maintain cilia. However, these mutations account for only half of the cases that have been studied, which indicates that mutations in other genes may also cause Joubert syndrome. Here, Stephen et al. used genetic techniques called ‘homozygosity mapping’ and ‘whole-exome sequencing’ to search for other mutations that might cause the disease. They found that mutations in a gene encoding a protein called KIAA0586 also cause Joubert syndrome in humans. One of these mutations (c.428delG) is unexpectedly common in the healthy human population. It might be a major contributor to Joubert syndrome, and the manifestation of Joubert syndrome in individuals with this mutation might depend on the presence and nature of other mutations in KIAA0586 and in other genes. The TALPID3 protein in chickens and other ‘model’ animals is the equivalent of human KIAA0586. A loss of TALPID3 protein in animals has been shown to stop cilia from forming. This protein is found in a structure called the basal body, which is part of a larger structure called the centrosome that anchors cilia to the cell. Here, Stephen et al. show that this is also true in mouse and human eye cells. Further experiments using chicken embryos show that a loss of the TALPID3 protein alters the location of centrosomes inside cells. TALPID3 is also required for cells and organs to develop the correct polarity, that is, directional differences in their structure and shape. The centrosomes of chicken brain cells that lacked TALPID3 were poorly positioned at the cell surface and abnormally long, which is likely responsible for the cilia failing to form. Stephen et al.'s findings suggest that KIAA0586 is also important for human development through its ability to control the centrosome. Defects in TALPID3 have a more severe effect on animal models than many of the identified KIAA0586 mutations have on humans. Therefore, the next step in this research is to find a more suitable animal in which to study the role of this protein, which may inform efforts to develop treatments for Joubert syndrome. DOI:http://dx.doi.org/10.7554/eLife.08077.002
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Malicdan MCV, Vilboux T, Stephen J, Maglic D, Mian L, Konzman D, Guo J, Yildirimli D, Bryant J, Fischer R, Zein WM, Snow J, Vemulapalli M, Mullikin JC, Toro C, Solomon BD, Niederhuber JE, Gahl WA, Gunay-Aygun M. Mutations in human homologue of chicken talpid3 gene (KIAA0586) cause a hybrid ciliopathy with overlapping features of Jeune and Joubert syndromes. J Med Genet 2015; 52:830-9. [PMID: 26386044 DOI: 10.1136/jmedgenet-2015-103316] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 08/24/2015] [Indexed: 01/20/2023]
Abstract
BACKGROUND In chicken, loss of TALPID3 results in non-functional cilia and short-rib polydactyly syndrome. This phenotype is caused by a frameshift mutation in the chicken ortholog of the human KIAA0586 gene, which encodes a novel coiled-coil domain protein essential for primary ciliogenesis, suggesting that KIAA0586 can be associated with ciliopathy in human beings. METHODS In our patients with ciliopathy (http://www.clinicaltrials.gov: NCT00068224), we have collected extensive clinical and neuroimaging data from affected individuals, and performed whole exome sequencing on DNA from affected individuals and their parents. We analysed gene expression on fibroblast cell line, and determined the effect of gene mutation on ciliogenesis in cells derived from patients. RESULTS We identified biallelic mutations in the human TALPID3 ortholog, KIAA0586, in six children with findings of overlapping Jeune and Joubert syndromes. Fibroblasts cultured from one of the patients with Jeune-Joubert syndrome exhibited more severe cilia defects than fibroblasts from patients with only Joubert syndrome; this difference was reflected in KIAA0586 RNA expression levels. Rescue of the cilia defect with full-length wild type KIAA0586 indicated a causal link between cilia formation and KIAA0586 function. CONCLUSIONS Our results show that biallelic deleterious mutations in KIAA0586 lead to Joubert syndrome with or without Jeune asphyxiating thoracic dystrophy. Furthermore, our results confirm that KIAA0586/TALPID3 is essential in cilia formation in human beings, expand the KIAA0586 phenotype to include features of Jeune syndrome and provide a pathogenetic connection between Joubert and Jeune syndromes, based on aberrant ciliogenesis.
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Bachmann-Gagescu R, Phelps IG, Dempsey JC, Sharma VA, Ishak GE, Boyle EA, Wilson M, Lourenço CM, Arslan M, Shendure J, Doherty D. KIAA0586 is Mutated in Joubert Syndrome. Hum Mutat 2015; 36:831-5. [PMID: 26096313 PMCID: PMC4537327 DOI: 10.1002/humu.22821] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 06/08/2015] [Indexed: 12/26/2022]
Abstract
Joubert syndrome (JS) is a recessive neurodevelopmental disorder characterized by a distinctive mid-hindbrain malformation. JS is part of a group of disorders called ciliopathies based on their overlapping phenotypes and common underlying pathophysiology linked to primary cilium dysfunction. Biallelic mutations in one of 28 genes, all encoding proteins localizing to the primary cilium or basal body, can cause JS. Despite this large number of genes, the genetic cause can currently be determined in about 62% of individuals with JS. To identify novel JS genes, we performed whole exome sequencing on 35 individuals with JS and found biallelic rare deleterious variants (RDVs) in KIAA0586, encoding a centrosomal protein required for ciliogenesis, in one individual. Targeted next-generation sequencing in a large JS cohort identified biallelic RDVs in eight additional families for an estimated prevalence of 2.5% (9/366 JS families). All affected individuals displayed JS phenotypes toward the mild end of the spectrum.
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Bachmann-Gagescu R, Dempsey JC, Phelps IG, O'Roak BJ, Knutzen DM, Rue TC, Ishak GE, Isabella CR, Gorden N, Adkins J, Boyle EA, de Lacy N, O'Day D, Alswaid A, Ramadevi A R, Lingappa L, Lourenço C, Martorell L, Garcia-Cazorla À, Ozyürek H, Haliloğlu G, Tuysuz B, Topçu M, Chance P, Parisi MA, Glass IA, Shendure J, Doherty D. Joubert syndrome: a model for untangling recessive disorders with extreme genetic heterogeneity. J Med Genet 2015; 52:514-22. [PMID: 26092869 PMCID: PMC5082428 DOI: 10.1136/jmedgenet-2015-103087] [Citation(s) in RCA: 191] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 06/01/2015] [Indexed: 12/23/2022]
Abstract
BACKGROUND Joubert syndrome (JS) is a recessive neurodevelopmental disorder characterised by hypotonia, ataxia, cognitive impairment, abnormal eye movements, respiratory control disturbances and a distinctive mid-hindbrain malformation. JS demonstrates substantial phenotypic variability and genetic heterogeneity. This study provides a comprehensive view of the current genetic basis, phenotypic range and gene-phenotype associations in JS. METHODS We sequenced 27 JS-associated genes in 440 affected individuals (375 families) from a cohort of 532 individuals (440 families) with JS, using molecular inversion probe-based targeted capture and next-generation sequencing. Variant pathogenicity was defined using the Combined Annotation Dependent Depletion algorithm with an optimised score cut-off. RESULTS We identified presumed causal variants in 62% of pedigrees, including the first B9D2 mutations associated with JS. 253 different mutations in 23 genes highlight the extreme genetic heterogeneity of JS. Phenotypic analysis revealed that only 34% of individuals have a 'pure JS' phenotype. Retinal disease is present in 30% of individuals, renal disease in 25%, coloboma in 17%, polydactyly in 15%, liver fibrosis in 14% and encephalocele in 8%. Loss of CEP290 function is associated with retinal dystrophy, while loss of TMEM67 function is associated with liver fibrosis and coloboma, but we observe no clear-cut distinction between JS subtypes. CONCLUSIONS This work illustrates how combining advanced sequencing techniques with phenotypic data addresses extreme genetic heterogeneity to provide diagnostic and carrier testing, guide medical monitoring for progressive complications, facilitate interpretation of genome-wide sequencing results in individuals with a variety of phenotypes and enable gene-specific treatments in the future.
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Alsaadi MM, Erzurumluoglu AM, Rodriguez S, Guthrie PAI, Gaunt TR, Omar HZ, Mubarak M, Alharbi KK, Al-Rikabi AC, Day INM. Nonsense mutation in coiled-coil domain containing 151 gene (CCDC151) causes primary ciliary dyskinesia. Hum Mutat 2015; 35:1446-8. [PMID: 25224326 PMCID: PMC4489323 DOI: 10.1002/humu.22698] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 09/04/2014] [Indexed: 01/10/2023]
Abstract
Primary ciliary dyskinesia (PCD) is an autosomal-recessive disorder characterized by impaired ciliary function that leads to subsequent clinical phenotypes such as chronic sinopulmonary disease. PCD is also a genetically heterogeneous disorder with many single gene mutations leading to similar clinical phenotypes. Here, we present a novel PCD causal gene, coiled-coil domain containing 151 (CCDC151), which has been shown to be essential in motile cilia of many animals and other vertebrates but its effects in humans was not observed until currently. We observed a novel nonsense mutation in a homozygous state in the CCDC151 gene (NM_145045.4:c.925G>T:p.[E309*]) in a clinically diagnosed PCD patient from a consanguineous family of Arabic ancestry. The variant was absent in 238 randomly selected individuals indicating that the variant is rare and likely not to be a founder mutation. Our finding also shows that given prior knowledge from model organisms, even a single whole-exome sequence can be sufficient to discover a novel causal gene.
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Marshall JD, Muller J, Collin GB, Milan G, Kingsmore SF, Dinwiddie D, Farrow EG, Miller NA, Favaretto F, Maffei P, Dollfus H, Vettor R, Naggert JK. Alström Syndrome: Mutation Spectrum of ALMS1. Hum Mutat 2015; 36:660-8. [PMID: 25846608 PMCID: PMC4475486 DOI: 10.1002/humu.22796] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 03/25/2015] [Accepted: 03/29/2015] [Indexed: 12/24/2022]
Abstract
Alström Syndrome (ALMS), a recessive, monogenic ciliopathy caused by mutations in ALMS1, is typically characterized by multisystem involvement including early cone-rod retinal dystrophy and blindness, hearing loss, childhood obesity, type 2 diabetes mellitus, cardiomyopathy, fibrosis, and multiple organ failure. The precise function of ALMS1 remains elusive, but roles in endosomal and ciliary transport and cell cycle regulation have been shown. The aim of our study was to further define the spectrum of ALMS1 mutations in patients with clinical features of ALMS. Mutational analysis in a world-wide cohort of 204 families identified 109 novel mutations, extending the number of known ALMS1 mutations to 239 and highlighting the allelic heterogeneity of this disorder. This study represents the most comprehensive mutation analysis in patients with ALMS, identifying the largest number of novel mutations in a single study worldwide. Here, we also provide an overview of all ALMS1 mutations identified to date.
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Roosing S, Hofree M, Kim S, Scott E, Copeland B, Romani M, Silhavy JL, Rosti RO, Schroth J, Mazza T, Miccinilli E, Zaki MS, Swoboda KJ, Milisa-Drautz J, Dobyns WB, Mikati MA, İncecik F, Azam M, Borgatti R, Romaniello R, Boustany RM, Clericuzio CL, D'Arrigo S, Strømme P, Boltshauser E, Stanzial F, Mirabelli-Badenier M, Moroni I, Bertini E, Emma F, Steinlin M, Hildebrandt F, Johnson CA, Freilinger M, Vaux KK, Gabriel SB, Aza-Blanc P, Heynen-Genel S, Ideker T, Dynlacht BD, Lee JE, Valente EM, Kim J, Gleeson JG. Functional genome-wide siRNA screen identifies KIAA0586 as mutated in Joubert syndrome. eLife 2015; 4:e06602. [PMID: 26026149 PMCID: PMC4477441 DOI: 10.7554/elife.06602] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 05/28/2015] [Indexed: 12/14/2022] Open
Abstract
Defective primary ciliogenesis or cilium stability forms the basis of human ciliopathies, including Joubert syndrome (JS), with defective cerebellar vermis development. We performed a high-content genome-wide small interfering RNA (siRNA) screen to identify genes regulating ciliogenesis as candidates for JS. We analyzed results with a supervised-learning approach, using SYSCILIA gold standard, Cildb3.0, a centriole siRNA screen and the GTex project, identifying 591 likely candidates. Intersection of this data with whole exome results from 145 individuals with unexplained JS identified six families with predominantly compound heterozygous mutations in KIAA0586. A c.428del base deletion in 0.1% of the general population was found in trans with a second mutation in an additional set of 9 of 163 unexplained JS patients. KIAA0586 is an orthologue of chick Talpid3, required for ciliogenesis and Sonic hedgehog signaling. Our results uncover a relatively high frequency cause for JS and contribute a list of candidates for future gene discoveries in ciliopathies. DOI:http://dx.doi.org/10.7554/eLife.06602.001 Joubert syndrome is a rare disorder that affects the brain and causes physical, mental, and sometimes visual impairments. In individuals with this condition, two parts of the brain called the cerebellar vermis and the brainstem do not develop properly. This is thought to be due to defects in the development and maintenance of tiny hair-like structures called cilia, which are found on the surface of cells. Currently, mutations in 25 different genes are known to be able to cause Joubert syndrome. However, these mutations only account for around 50% of the cases that have been studied, and the ‘unexplained’ cases suggest that mutations in other genes may also cause the disease. Here, Roosing et al. used a technique called a ‘genome-wide siRNA screen’ to identify other genes regulating the formation of cilia that might also be connected with Joubert syndrome. This approach identified almost 600 candidate genes. The data from the screen were combined with gene sequence data from 145 individuals with unexplained Joubert syndrome. Roosing et al. found that individuals with Joubert syndrome from 15 different families had mutations in a gene called KIAA0586. In chickens and mice, this gene—known as Talpid3—is required for the formation of cilia. Roosing et al.'s findings reveal a new gene that is involved in Joubert syndrome and also provides a list of candidate genes for future studies of other conditions caused by defects in the formation of cilia. The next challenges are to find out what causes the remaining unexplained cases of the disease and to understand what roles the genes identified in this study play in cilia. DOI:http://dx.doi.org/10.7554/eLife.06602.002
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Abstract
Skeletal dysplasias result from disruptions in normal skeletal growth and development and are a major contributor to severe short stature. They occur in approximately 1/5,000 births, and some are lethal. Since the most recent publication of the Nosology and Classification of Genetic Skeletal Disorders, genetic causes of 56 skeletal disorders have been uncovered. This remarkable rate of discovery is largely due to the expanded use of high-throughput genomic technologies. In this review, we discuss these recent discoveries and our understanding of the molecular mechanisms behind these skeletal dysplasia phenotypes. We also cover potential therapies, unusual genetic mechanisms, and novel skeletal syndromes both with and without known genetic causes. The acceleration of skeletal dysplasia genetics is truly spectacular, and these advances hold great promise for diagnostics, risk prediction, and therapeutic design.
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Atkinson KF, Kathem SH, Jin X, Muntean BS, Abou-Alaiwi WA, Nauli AM, Nauli SM. Dopaminergic signaling within the primary cilia in the renovascular system. Front Physiol 2015; 6:103. [PMID: 25932013 PMCID: PMC4399208 DOI: 10.3389/fphys.2015.00103] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 03/13/2015] [Indexed: 12/15/2022] Open
Abstract
Activation of dopamine receptor type-5 (DR5) has been known to reduce systemic blood pressure, most likely by increasing renal vasodilation and enhancing natriuresis in the kidney. However, the mechanism of DR5 in natriuresis and vasodilation was not clearly known. We have previously shown that DR5 is localized to primary cilia of proximal renal epithelial and vascular endothelial cells. We here show that selective activation of DR5 specifically induces calcium influx only in the primary cilia, whereas non-selective activation of dopamine receptor induces calcium fluxes in both cilioplasm and cytoplasm. Cilia-independent signaling induced by thrombin only shows calcium signaling within cytoplasm. Furthermore, calcium activation in the cilioplasm by DR5 increases length and mechanosensory function of primary cilia, leading to a greater response to fluid-shear stress. We therefore propose a new mechanism by which DR5 induces vasodilation via chemical and mechanical properties that are specific to primary cilia.
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Bayram Y, Aydin H, Gambin T, Akdemir ZC, Atik MM, Karaca E, Karaman A, Pehlivan D, Jhangiani SN, Gibbs RA, Lupski JR. Exome sequencing identifies a homozygous C5orf42 variant in a Turkish kindred with oral-facial-digital syndrome type VI. Am J Med Genet A 2015; 167A:2132-7. [PMID: 25846457 DOI: 10.1002/ajmg.a.37092] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Accepted: 03/16/2015] [Indexed: 11/08/2022]
Abstract
Oral-facial-digital syndrome type VI (OFDVI) is a rare ciliopathy in the spectrum of Joubert syndrome (JS) and distinguished from other oral-facial-digital syndromes by metacarpal abnormalities with central polydactyly and by a molar tooth sign on cranial MRI. Additional characteristic features include short stature, micrognathia, posteriorly rotated low-set ears, hypertelorism, epicanthal folds, broad nasal tip, tongue hamartoma, upper lip notch, intraoral frenula, cleft lip/palate, and renal anomalies. Recently, novel mutations in C5orf42 were identified in 9 out of 11 OFDVI families. In a subsequent study C5orf42 was found to be mutated in only 2 out of 17 OFDVI probands while 28 patients with a pure JS phenotype also had pathogenic mutations of C5orf42. We report on two affected cousins diagnosed with OFDVI who were born from first degree cousin marriages. Whole exome sequencing (WES) identified a homozygous predicted damaging missense mutation (c.4034A > G; p.Gln1345Arg) in the C5orf42 gene. Our data contribute to the evidence that C5orf42 is one of the causative genes for OFDVI.
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Abstract
PURPOSE OF REVIEW Nephronophthisis (NPHP) is an autosomal recessive cystic kidney disease and is one of the most common genetic disorders causing end-stage renal disease (ESRD) in children and adolescents. NPHP is a genetically heterogenous disorder with 20 identified genes. NPHP occurs as an isolated kidney disease, but approximately 15% of NPHP patients have additional extrarenal symptoms affecting other organs [e.g. eyes, liver, bones and central nervous system (CNS)]. The pleiotropy in NPHP is explained by the finding that almost all NPHP gene products share expression in primary cilia, a sensory organelle present in most mammalian cells. If extrarenal symptoms are present in addition to NPHP, these disorders are classified as NPHP-related ciliopathies (NPHP-RC). This review provides an update about recent advances in the field of NPHP-RC. RECENT FINDINGS The identification of novel disease-causing genes has improved our understanding of the pathomechanisms contributing to NPHP-RC. Multiple interactions between different NPHP-RC gene products have been published and outline the interconnectivity of the affected proteins and shared pathways. SUMMARY The significance of recently identified genes for NPHP-RC is discussed and the complex role and interaction of NPHP proteins in ciliary function and cellular signalling pathways is highlighted.
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MESH Headings
- Adaptor Proteins, Signal Transducing/metabolism
- Adolescent
- Child
- Cilia/pathology
- Cilia/physiology
- Cytoskeletal Proteins
- Genes, Recessive
- Humans
- Kidney/pathology
- Kidney Diseases, Cystic/complications
- Kidney Diseases, Cystic/congenital
- Kidney Diseases, Cystic/pathology
- Kidney Diseases, Cystic/physiopathology
- Kidney Failure, Chronic/etiology
- Kidney Failure, Chronic/genetics
- Kidney Failure, Chronic/pathology
- Kidney Failure, Chronic/physiopathology
- Membrane Proteins/metabolism
- Mutation/genetics
- Phenotype
- Signal Transduction
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