Treacher Collins syndrome 1

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Description from OMIM

Treacher Collins syndrome is a disorder of craniofacial development. The features include antimongoloid slant of the eyes, coloboma of the lid, micrognathia, microtia and other deformity of the ears, hypoplastic zygomatic arches, and macrostomia. Conductive hearing loss and cleft palate are often present (Dixon, 1996). Genetic Heterogeneity of Treacher Collins Syndrome Treacher Collins syndrome-2 (TCS2; 613717) is caused by heterozygous mutation in the POLR1D gene (613715) on chromosome 13q12.2. Treacher Collins syndrome-3 (TCS3; 248390) is caused by compound heterozygous mutation in the POLR1C gene (610060) on chromosome 6.

Prevalence of clinical parameters (%)

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Number of patients in the reference Percent affected patients (Between 0 and 1, eg. 0.1 = 10%)
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List of symptoms

Symptom/sign Organ system Percent affected Pubmed id Added on(yyyy-mm-dd) Edit/add reference
Downward sloping palpebral apertures skeletal 100 % 15340364 2015-02-27
Zygomatic hypoplasia skeletal 97 % 15340364 2015-02-27
Micrognathia skeletal 91 % 15340364 2015-02-27
Conductive hearing loss skeletal 83 % 15340364 2015-02-27
Microtia integumentary 71 % 15340364 2015-02-27
Ear malformation integumentary 71 % 15340364 2015-02-27
Ear canal atresia integumentary 67 % 15340364 2015-02-27
Speech delay nervous 57 % 15340364 2015-02-27
Lower eyelid coloboma integumentary 54 % 15340364 2015-02-27
Cleft lip or palate integumentary 33 % 15340364 2015-02-27
Choanal stenosis digestive 25 % 15340364 2015-02-27
Preauricular tags integumentary 24 % 15340364 2015-02-27
Tracheostoma respiratory 12 % 15340364 2015-02-27
Developmental delay nervous 10 % 15340364 2015-02-27

List of references:

Genotyping in 46 patients with tentative diagnosis of Treacher Collins syndrome revealed unexpected phenotypic variation.
Ozge Altug Teber, Gabriele Gillessen-Kaesbach, Sven Fischer, Stefan Böhringer, Beate Albrecht, Angelika Albert, Mine Arslan-Kirchner, Eric Haan, Monika Hagedorn-Greiwe, Christof Hammans, Wolfram Henn, Georg Klaus Hinkel, Rainer König, Erdmute Kunstmann, Jürgen Kunze, Luitgard M Neumann, Eva-Christina Prott, Anita Rauch, Hans-Dieter Rott, Heide Seidel, Stephanie Spranger, Martin Sprengel, Barbara Zoll, Dietmar R Lohmann, Dagmar Wieczorek,

To define the range of phenotypic expression in Treacher Collins syndrome (TCS; Franceschetti-Klein syndrome), we performed mutation analysis in the TCOF1 gene in 46 patients with tentative diagnosis of TCS and evaluated the clinical data, including a scoring system. A total of 27 coding exons of TCOF1 and adjacent splice junctions were analysed by direct sequencing. In 36 patients with a clinically unequivocal diagnosis of TCS, we detected 28 pathogenic mutations, including 25 novel alterations. No mutation was identified in the remaining eight patients with unequivocal diagnosis of TCS and 10 further patients, in whom the referring diagnosis of TCS was clinically doubtful. There is no overt genotype-phenotype correlation except that conductive deafness is significantly less frequent in patients with mutations in the 3' part of the open reading frame. Inter- and intrafamilial variation is wide. Some mutation carriers, parents of typically affected patients, are so mildly affected that the diagnosis might be overlooked clinically. This suggests that modifying factors are important for phenotypic expression. Based on these findings, minimal diagnostic criteria were defined: downward slanting palpebral fissures and hypoplasia of the zygomatic arch. The difficulties in genetic counselling, especially diagnosis of family members with a mild phenotype, are described.

European journal of human genetics : EJHG - Nov 2004