Treacher Collins syndrome (TCS) is a disorder of craniofacial development. The features include downslanting palpebral fissures, coloboma of the eyelid, micrognathia, microtia and other deformity of the ears, hypoplastic zygomatic arches, and macrostomia. Conductive hearing loss and cleft palate are often present (summary by Dixon, 1996).
Genetic Heterogeneity of Treacher Collins Syndrome
Treacher Collins syndrome-2 (TCS2; 613717) is caused by mutation in the POLR1D gene (613715) on chromosome 13q12. Treacher Collins syndrome-3 (TCS3; 248390) is caused by mutation in the POLR1C gene (610060) on chromosome 6p21. Treacher Collins syndrome-4 (TCS4; 618939) is caused by mutation in the POLR1B gene (602000) on chromosome 2q14. [from OMIM]
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