Down Syndrome ( Ds ) Or Trisomy 21 Essay

2159 Words Sep 13th, 2016 9 Pages
Down Syndrome

Down syndrome (DS) or trisomy 21 is caused by the presence of an extra copy of all or a part of the p arm of chromosome 21 predisposing to complex and multisystemic phenotypes1. DS is one of the most common chromosomal disorder and the most common genetic cause of intellectual disability 2. Around half of children born with DS develops congenital heart disease 3. The most common cause (95%) of DS is non-disjunction of chromosome 21 during meiosis of gametogenesis while other rare mechanisms such as translocation and mosaicism account for about 5% of DS cases 4,5. In this essay the DS disease phenotypes, disease incidence, history of gene identification, cause of disease in terms of gene and chromosome abnormalities, gene function and related phenotypes, current treatment approaches, potential future treatments and ethics around screening of disease will be discussed.

The common variable clinical phenotypes of DS include learning and memory difficulties, craniofacial abnormalities, hypotonia and presence of Alzheimer disease related pathology in DS patient over the age of 40 years 6,7. Also, minimum of 80 other variable phenotypes are observed in subpopulation of DS, comprising of atrioventricular septal heart defects, neurological complications such as epilepsy and obstructive sleep apnea, acute megakaryoblastic leukaemia, high infections, gastrointestinal disorders, hearing loss, ophthalmological problems, and respiratory complications 8-10. Other common…

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