Turner syndrome: Difference between revisions
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=== Phenotype === | === Phenotype === | ||
The affected person is phenotypically female but does not undergo sexual maturation<ref>Hartl D. L., Ruvolo M. (2012) Genetics Analysis of Genes and Genomes, Eighth edition(international edition), London: Jones &amp;amp; Bartlett Learning International. p273</ref>. This leads to poor breast development (with the nipples spread a distance apart) <ref>Anthony JF Griffiths et al., 1990, Modern Genetic Analysis, New York : W.H.Freeman, Chapter 8</ref> and the absence of menstruation<ref>''Puberty/Reproduction'' http://turners.nichd.nih.gov/clinical.html</ref>. Other phenotypes present include being short in stature, having a low hairline,a webbed neck and having small finger nails. Also, the constriction of the aorta is another phenotype of this syndrome. However, mental abilities are typically within the normal range<ref>Hartl D. L., Ruvolo M. (2012) Genetics Analysis of Genes and Genomes, Eighth edition(international edition), London: Jones &amp;amp; Bartlett Learning International. p273</ref>. Furthermore different karyotypes found in patients with Turner Syndrome will manifest themselves as different phenotypes of the disease<ref name="null">Al Alwan, Khadora M et.al. 2014. Turner Syndrome Genotype and phenotype and their effect on presenting features and timing of Diagnosis.(www.ncbi.nlm.nih.gov/pmc/articles/PMC4166992/) (22/10/2014)</ref>. However more than 99 percent of (turner syndrome) foetuses undergo spontaneous abortion. this indicates that the condition has profound deleterious effects on development<ref>Hartl D. L., Ruvolo M. (2012) Genetics Analysis of Genes and Genomes, Eighth edition(international edition), London: Jones &amp;amp; Bartlett Learning International. p273</ref>. | The affected person is phenotypically female but does not undergo sexual maturation<ref>Hartl D. L., Ruvolo M. (2012) Genetics Analysis of Genes and Genomes, Eighth edition(international edition), London: Jones &amp;amp;amp; Bartlett Learning International. p273</ref>. This leads to poor breast development (with the nipples spread a distance apart) <ref>Anthony JF Griffiths et al., 1990, Modern Genetic Analysis, New York : W.H.Freeman, Chapter 8</ref> and the absence of menstruation<ref>''Puberty/Reproduction'' http://turners.nichd.nih.gov/clinical.html , January 2, 2012.</ref>. Other phenotypes present include being short in stature, having a low hairline,a webbed neck and having small finger nails. Also, the constriction of the aorta is another phenotype of this syndrome. However, mental abilities are typically within the normal range<ref>Hartl D. L., Ruvolo M. (2012) Genetics Analysis of Genes and Genomes, Eighth edition(international edition), London: Jones &amp;amp;amp; Bartlett Learning International. p273</ref>. Furthermore different karyotypes found in patients with Turner Syndrome will manifest themselves as different phenotypes of the disease<ref name="null">Al Alwan, Khadora M et.al. 2014. Turner Syndrome Genotype and phenotype and their effect on presenting features and timing of Diagnosis.(www.ncbi.nlm.nih.gov/pmc/articles/PMC4166992/) (22/10/2014)</ref>. However more than 99 percent of (turner syndrome) foetuses undergo spontaneous abortion. this indicates that the condition has profound deleterious effects on development<ref>Hartl D. L., Ruvolo M. (2012) Genetics Analysis of Genes and Genomes, Eighth edition(international edition), London: Jones &amp;amp;amp; Bartlett Learning International. p273</ref>. | ||
= References = | = References = | ||
Revision as of 19:52, 25 November 2014
Turner Syndrome is a monosomic condition in which only one X chromosome is present (XO). This presents itself as 45,X in terms of karyotype.
Karyotype
Instead of having a set of 44 autosomes + 1 pair of sex chromosomes (either XX or XY) - the normal human karyotype, the person has only 44 autosomes + 1 X chromosomes. A person with Turner syndrome will have no barr bodies due to them only have 1 X chromosome.
Cause
Turner syndrome occurs as a result of nondisjunction, which is when chromosomes do not separate successfully during meiosis. It happens in about 1 in 5000 female births.
Phenotype
The affected person is phenotypically female but does not undergo sexual maturation[1]. This leads to poor breast development (with the nipples spread a distance apart) [2] and the absence of menstruation[3]. Other phenotypes present include being short in stature, having a low hairline,a webbed neck and having small finger nails. Also, the constriction of the aorta is another phenotype of this syndrome. However, mental abilities are typically within the normal range[4]. Furthermore different karyotypes found in patients with Turner Syndrome will manifest themselves as different phenotypes of the disease[5]. However more than 99 percent of (turner syndrome) foetuses undergo spontaneous abortion. this indicates that the condition has profound deleterious effects on development[6].
References
- ↑ Hartl D. L., Ruvolo M. (2012) Genetics Analysis of Genes and Genomes, Eighth edition(international edition), London: Jones &amp;amp; Bartlett Learning International. p273
- ↑ Anthony JF Griffiths et al., 1990, Modern Genetic Analysis, New York : W.H.Freeman, Chapter 8
- ↑ Puberty/Reproduction http://turners.nichd.nih.gov/clinical.html , January 2, 2012.
- ↑ Hartl D. L., Ruvolo M. (2012) Genetics Analysis of Genes and Genomes, Eighth edition(international edition), London: Jones &amp;amp; Bartlett Learning International. p273
- ↑ Al Alwan, Khadora M et.al. 2014. Turner Syndrome Genotype and phenotype and their effect on presenting features and timing of Diagnosis.(www.ncbi.nlm.nih.gov/pmc/articles/PMC4166992/) (22/10/2014)
- ↑ Hartl D. L., Ruvolo M. (2012) Genetics Analysis of Genes and Genomes, Eighth edition(international edition), London: Jones &amp;amp; Bartlett Learning International. p273