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Term paper - Courtney Boyd Bio 361 Section 001 Dr. Brenda...

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Courtney Boyd Bio 361 Section 001 Dr. Brenda Grubb November 11, 2010 Treacher Collins Syndrome Abstract Treacher Collins syndrome is an autosomal dominant disorder that affects the development of the face and head. It consist of several malformations of the face and can also affect the development of the middle ear resulting in deafness. It is derived from neural crest cells which contain the gene TCOF1. Treacher Collins syndrome results when there is a loss-of-function mutation in the TCOF1 gene which encodes Treacle. Treacle is a nucleolar phosphoprotein that is and plays a central role in pre-ribosomal processing and ribosomal biogenesis. There is depletion and a reduced number in neural crest cells due to haploinsufficiency in mice. This results in high levels of cell death in the neuraoepithelium. Introduction Treacher Collins syndrome, also known as manidibulofacial dysostosis, is an autosomal dominant disorder which derived from neural crest cells and affects the development of the head and face. Even though it is often found to be autosomal dominant, there is a possibility that it could be autosomal recessive as well. Treacher Collins syndrome has been found in several races such as Caucasians, African Americans, Chinese, Japanese, and Asiatic Indians.Dixon states that Treacher Collins syndrome affects the development of the face in about 1 in 50,000 live births and is thought to be the result of a de novo mutation. However, there are several theories proposed to explain the cellular basis of the tissues that are affected within the cranial neural crest. These theories that were proposed include abnormal neural crest cell migration, improper cellular differentiation during development, or an abnormality of the extracellular matrix. In fact, a mutated gene known as TCOF1 was identified using genetic, physical, and transcript mapping techniques. Treacle, which is encoded by TCOF1, is defined as a low complexity, serine/alanine-rich, nucleolar phosphoprotein. Treacher Collins syndrome consists of major clinical features such as abnormalities of the external ear, atresia of external auditory canals, deep eyelid furrows, and malar hypoplasia. Hearing loss is often a result of these major clinical features. Other features of Treacher Collins syndrome are coloboma which is a defect of the lower eye, small jaw, large mouth, cleft palate, and the scalp reaches to the cheeks. The other features that occur occasionally include pharyngeal hypoplasia which is the underdevelopment of the pharynx, notches of the upper lid, bony or membranous closure of one or both of the openings between the nasal cavity and the nasopharynx, congenital heart defect, and absence of the parotid gland . Research was conducted by Dixon on the molecular genetics of Treacher Collins
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This note was uploaded on 11/26/2011 for the course BIO 361 taught by Professor Dr.bjgrubb during the Fall '10 term at N.C. A&T.

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Term paper - Courtney Boyd Bio 361 Section 001 Dr. Brenda...

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