scholarly journals A Recurrent Variant in POLR1B, c.3007C>T; p.Arg1003Cys, Associated with Atresia of the External Canal and Microtia in Treacher Collins Syndrome Type 4

2021 ◽  
Vol 12 (2) ◽  
pp. 127-132
Author(s):  
Yumi Enomoto ◽  
Yoshinori Tsurusaki ◽  
Makiko Tominaga ◽  
Shinji Kobayashi ◽  
Maki Inoue ◽  
...  
Keyword(s):  
Conductive Hearing Loss ◽  
Rna Polymerase I ◽  
Treacher Collins Syndrome ◽  
Phenotype Correlation ◽  
Causative Gene ◽  
Mandibular Hypoplasia ◽  
Pathogenic Variants ◽  
External Canal ◽  
Polymerase I ◽  
Conductive Hearing

Treacher Collins syndrome (TCS) is a heterogenous malformation syndrome characterized by a distinct facial appearance including downslanting palpebral fissures, malar hypoplasia, conductive hearing loss, and mandibular hypoplasia. Recently, a new causative gene, <i>POLR1B</i>, encoding DNA-directed RNA polymerase I subunit RPA2, was identified as a fourth type of TCS (TCS4). We describe another patient with TCS4 caused by a recurrent <i>POLR1B</i> variant, c.3007C&#x3e;T; p.Arg1003Cys. Including our patient, all 4 patients with p.(Arg1003Cys) had atresia of the external auditory canal and microtia. All of the reported pathogenic variants in <i>POLR1B</i> were clustered at only 2 residues. Our patient highlights the genotype-phenotype correlation in TCS4 associated with <i>POLR1B</i>.

scholarly journals Treacher Collins Syndrome: Genetics, Clinical Features and Management

Genes ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1392
Author(s):  
Bożena Anna Marszałek-Kruk ◽  
Piotr Wójcicki ◽  
Krzysztof Dowgierd ◽  
Robert Śmigiel
Keyword(s):  
Hearing Loss ◽  
Fetal Development ◽  
Conductive Hearing Loss ◽  
Choanal Atresia ◽  
Treacher Collins Syndrome ◽  
Lateral Part ◽  
Pharyngeal Arches ◽  
Live Births ◽  
Pathogenic Variants ◽  
Conductive Hearing

Treacher Collins syndrome (TCS) is associated with abnormal differentiation of the first and second pharyngeal arches, occurring during fetal development. Features of TCS include microtia with conductive hearing loss, slanting palpebral fissures with possibly coloboma of the lateral part of lower eyelids, midface hypoplasia, micrognathia as well as sporadically cleft palate and choanal atresia or stenosis. TCS occurs in the general population at a frequency of 1 in 50,000 live births. Four subtypes of Treacher Collins syndrome exist. TCS can be caused by pathogenic variants in the TCOF1, POLR1D, POLR1C and POLR1B genes. Genetically, the TCOF1 gene contains 27 exons which encodes the Treacle protein. In TCOF1, over 200 pathogenic variants have been identified, of which most are deletions leading to a frame-shift, that result in the formation of a termination codon. In the presented article, we review the genetics and phenotype of TCS as well as the management and surgical procedures utilized for treatment.

scholarly journals Mild Form of Treacher Collins Syndrome Imitating Juvenile Otosclerosis

2012 ◽  
Vol 2012 ◽  
pp. 1-3
Author(s):  
Karol Zeleník ◽  
Pavel Komínek
Keyword(s):  
Early Childhood ◽  
Hearing Loss ◽  
Middle Ear ◽  
Developmental Disorder ◽  
Conductive Hearing Loss ◽  
Treacher Collins Syndrome ◽  
Mild Form ◽  
Ear Anomalies ◽  
Conductive Hearing ◽  
Surgical Corrections

Treacher Collins syndrome (TCS) is an inherited developmental disorder. More than 40% of individuals with TCS have conductive hearing loss attributed to external and middle ear anomalies. Mild cases of TCS often pass undiagnosed at birth or early childhood. The disease may be manifested as conductive hearing loss in teenagers and may resemble juvenile otosclerosis. Patients could suffer from slight facial variabilities including retrognathia (as in our case) and others, which point out to a possible middle ear anomaly. Surgical corrections of middle ear anomalies including TCS generally lead to poorer outcomes comparing with juvenile otosclerosis, which should be discussed with parents during preoperative counselling.

scholarly journals Treacher Collins syndrome mutations in Saccharomyces cerevisiae destabilize RNA polymerase I and III complex integrity

2017 ◽  
Vol 26 (21) ◽  
pp. 4290-4300 ◽  
Author(s):  
Nancy Walker-Kopp ◽  
Ashleigh J Jackobel ◽  
Gianno N Pannafino ◽  
Paola A Morocho ◽  
Xia Xu ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Rna Polymerase ◽  
Rna Polymerase I ◽  
Treacher Collins Syndrome ◽  
Polymerase I

scholarly journals Ear Surgery in Treacher Collins Syndrome

1995 ◽  
Vol 104 (1) ◽  
pp. 31-41 ◽  
Author(s):  
Henri A. M. Marres ◽  
H. M. A. Marres ◽  
W. R. J. Cremers ◽  
Patrick L. M. Huygen
Keyword(s):  
Hearing Loss ◽  
Autosomal Dominant ◽  
Conductive Hearing Loss ◽  
Branchial Arch ◽  
Treacher Collins Syndrome ◽  
Ear Surgery ◽  
Arch System ◽  
Conductive Hearing ◽  
Outcome Of Surgery ◽  
Insight Into

The autosomal dominant hereditary Treacher Collins syndrome manifests itself phenotypically in dysmorphogenesis of particularly the first, but also the second branchial arch system. Consequently, 50% of patients with Treacher Collins syndrome have a congenital, generally pure conductive hearing loss resulting from a major or minor ear anomaly. The outcome of surgery to improve patients' hearing varies and is sometimes even disappointing. Thorough analysis of 33 cases (39 operated ears) and the strict application of a classification for the anomaly to each ear enabled us to gain insight into the most suitable surgical policy and to form a prognosis for reconstructive ear surgery.

Speech and voice rehabilitation in selected patients fitted with a bone anchored hearing aid (BAHA)

1996 ◽  
Vol 110 (21) ◽  
pp. 47-51 ◽  
Author(s):  
Julie Thomas
Keyword(s):  
Hearing Loss ◽  
Speech Therapy ◽  
Conductive Hearing Loss ◽  
Treacher Collins Syndrome ◽  
Voice Rehabilitation ◽  
Osseointegrated Implant ◽  
Spontaneous Improvement ◽  
Bone Anchored Hearing Aid ◽  
Characteristic Features ◽  
Conductive Hearing

AbstractWithin the Birmingham osseointegrated implant programme there have been several patients with severe pre-lingual conductive hearing loss. The majority of these have been patients with Treacher Collins syndrome.There are characteristic features of speech and voice in those with long-standing conductive hearing loss. In addition, the associated abnormalities of jaw, teeth and palate may amplify the problem. There may be spontaneous improvement in features such as voice pitch, quality and intensity following the fitting of a BAHA. However, in those with a pre-lingual hearing impairment, speech therapy may be necessary. Patients assessed as suitable for BAHA have a full assessment of communication skills including audio recording of speech and voice. Post-operative training improves auditory discrimination and perception and is followed by training in the production of the newly perceived speech sounds.

scholarly journals The Roles of RNA Polymerase I and III Subunits Polr1c and Polr1d in Craniofacial Development and in Zebrafish Models of Treacher Collins Syndrome

PLoS Genetics ◽  
2016 ◽  
Vol 12 (7) ◽  
pp. e1006187 ◽  
Author(s):  
Kristin E. Noack Watt ◽  
Annita Achilleos ◽  
Cynthia L. Neben ◽  
Amy E. Merrill ◽  
Paul A. Trainor
Keyword(s):  
Rna Polymerase ◽  
Craniofacial Development ◽  
Rna Polymerase I ◽  
Treacher Collins Syndrome ◽  
Polymerase I

Hearing Loss in Children with Craniofacial Microsomia

2017 ◽  
Vol 54 (6) ◽  
pp. 656-663 ◽  
Author(s):  
Ryan M. Mitchell ◽  
Babette S. Saltzman ◽  
Susan J. Norton ◽  
Robert G. Harrison ◽  
Carrie L. Heike ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Retrospective Cohort ◽  
Facial Nerve Palsy ◽  
Conductive Hearing Loss ◽  
Tertiary Care ◽  
Mandibular Hypoplasia ◽  
Craniofacial Microsomia ◽  
The Mean ◽  
Conductive Hearing

Objective To evaluate the association between craniofacial phenotype and hearing loss in children with craniofacial microsomia. Design Retrospective cohort study. Setting Tertiary care children's hospital. Patients Individuals with craniofacial microsomia. Main Outcome Measures Ear-specific audiograms and standardized phenotypic classification of facial characteristics. Results A total of 79 participants were included in the study. The mean age was 9 years (range, 1 to 23 years) and approximately 60% were boys. Facial anomalies were bilateral in 39 participants and unilateral in 40 participants (24 right, 16 left). Microtia (hypoplasia of the ear) was the most common feature (94%), followed by mandibular hypoplasia (76%), soft tissue deficiency (60%), orbital hypoplasia or displacement (53%), and facial nerve palsy (32%). Sixty-five individuals had hearing loss (12 bilateral and 53 unilateral). Hearing loss was conductive in 73% of affected ears, mixed in 10%, sensorineural in 1%, and indeterminate in 16%. Hypoplasia of the ear or mandible was frequently associated with ipsilateral hearing loss, although contralateral hearing loss occurred in 8% of hemifaces. Conclusions Hearing loss is strongly associated with malformations of the ipsilateral ear in craniofacial microsomia and is most commonly conductive. Hearing loss can occur contralaterally to the side with malformations in children with apparent hemifacial involvement. Children with craniofacial microsomia should receive early diagnostic hearing assessments.

Ear Malformation and Hearing Loss in Patients with Treacher Collins Syndrome

1993 ◽  
Vol 30 (1) ◽  
pp. 97-103 ◽  
Author(s):  
Gaylene Pron ◽  
Cheryl Galloway ◽  
Derek Armstrong ◽  
Jeffrey Posnick
Keyword(s):  
Hearing Loss ◽  
Inner Ear ◽  
Middle Ear ◽  
Conductive Hearing Loss ◽  
Treacher Collins Syndrome ◽  
External Ear ◽  
Ear Canal ◽  
Ear Malformations ◽  
Asymmetric Hearing Loss ◽  
Conductive Hearing

Although the hearing loss of patients with Treacher Collins syndrome is well documented, few studies have reported jointly on their hearing loss and ear pathology. This paper reports on the hearing loss and computerized tomography (CT) assessments of ear malformations in a large pediatric series of patients with Treacher Collins. Of the 29 subjects assessed by the Craniofacial Program between 1986 and 1990, paired audiologic and complete CT assessments were available for 23 subjects. The external ear canal abnormalities were largely symmetric, either bilaterally stenotic or atretic. In most cases, the middle ear cavity was bilaterally hypoplastic and dysmorphic, and ossicles were symmetrically dysmorphic or missing. Inner ear structures were normal in all patients. The majority of patients had a unilateral or bilateral moderate or greater degree of hearing loss and almost half had an asymmetric hearing loss. The hearing loss of all subjects was conductive, except for three whose loss was bilateral mixed. Two types of bilaterally symmetric hearing loss configurations, flat and reverse sloping, were noted. Conductive hearing loss in patients with Treacher Collins is mainly attributable to their middle ear malformations, which are similar for those of patients with malformed or missing ossicles.

A role for upstream binding factor in organizing ribosomal gene chromatin

2006 ◽  
Vol 73 ◽  
pp. 77-84 ◽  
Author(s):  
Jane E. Wright ◽  
Christine Mais ◽  
José-Luis Prieto ◽  
Brian McStay
Keyword(s):  
Nucleolar Organizer ◽  
Ribosomal Gene ◽  
Rna Polymerase I ◽  
Nucleolar Organizer Regions ◽  
Binding Factor ◽  
Upstream Binding Factor ◽  
Acrocentric Chromosomes ◽  
Polymerase I ◽  
Secondary Constrictions ◽  
Active Nors

Human ribosomal genes are located in NORs (nucleolar organizer regions) on the short arms of acrocentric chromosomes. During metaphase, previously active NORs appear as prominent chromosomal features termed secondary constrictions, which are achromatic in chromosome banding and positive in silver staining. The architectural RNA polymerase I transcription factor UBF (upstream binding factor) binds extensively across the ribosomal gene repeat throughout the cell cycle. Evidence that UBF underpins NOR structure is provided by an examination of cell lines in which large arrays of a heterologous UBF binding sequences are integrated at ectopic sites on human chromosomes. These arrays efficiently recruit UBF even to sites outside the nucleolus, and during metaphase form novel silver-stainable secondary constrictions, termed pseudo-NORs, that are morphologically similar to NORs.

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