GTR Home > Conditions/Phenotypes > Treacher Collins syndrome 2


Excerpted from the GeneReview: Treacher Collins Syndrome
Treacher Collins syndrome (TCS) is characterized by hypoplasia of the zygomatic bones and mandible, external ear abnormalities, coloboma (notching) of the lower eyelid, absence of the lower eyelashes, and preauricular hair displacement onto the cheeks. About 40%-50% of individuals have conductive hearing loss attributed most commonly to malformation (including ankylosis, hypoplasia, or absence) of the ossicles and hypoplasia of the middle ear cavities. Inner ear structures tend to be normal. Other less common abnormalities include cleft palate with or without cleft lip and unilateral or bilateral choanal stenosis or atresia.

Available tests

37 tests are in the database for this condition.

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Genes See tests for all associated and related genes

  • Also known as: AC19, POLR1C, RPA16, RPA9, RPAC2, RPC16, RPO1-3, TCS2, POLR1D
    Summary: RNA polymerase I and III subunit D

Clinical features


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