wikipedia - triple x syndrome (checked)

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Triple X syndrome

Classification and external resources

ICD-10 Q97.0 (http://apps.who.int

/classifications/icd10/browse/2015/en#

/Q97.0)

DiseasesDB 13386

(http://www.diseasesdatabase.com

/ddb13386.htm)

Triple X syndromeFrom Wikipedia, the free encyclopedia

Triple X syndrome(also known as triplo-X, trisomy

X, XXX syndrome, 47,XXX aneuploidy) is a form

of chromosomal variation characterized by thepresence of an extra X chromosome in each cell of a

human female. Females with triple X syndrome have

three X chromosomes instead of two. The karyotype

reads 47,XXX because the affected individual has 47

chromosomes, as opposed to the usual 46. A mosaic

form also occurs where only a percentage of the body

cells contain XXX while the remainder carry XX. The

extent to which an individual is affected by the

condition will depend upon the proportion of XXX to

XX throughout.[1]Triple X results during division of a parent's reproductive cells and occurs about once

in every 1,000 female births. Unlike most other chromosomal conditions (such as Down syndrome),there is usually no distinguishable difference to the naked eye between those with triple X and the rest of

the female population.

Contents

1 Cause

2 Symptoms

3 Incidence

4 First case5 Diagnosis

6 See also

7 References

8 External links

Cause

Triple X syndrome is not inherited, but usually occurs as an event during the formation of reproductive

cells (ovum and sperm). An error in cell division called nondisjunction can result in reproductive cellswith additional chromosomes. For example, an oocyte or sperm cell may gain an extra copy of the X

chromosome as a result of the non-disjunction. If one of these cells contributes to the genetic makeup of

a child, the child will have an extra X chromosome in each of her cells. In some cases, trisomy X occurs

during cell division in early embryonic development.

Some females with triple X syndrome have an extra X chromosome in only some of their cells. These

Triple X syndrome - Wikipedia, the free encyclopedia http://en.wikipedia.org/wiki/Triple_X_synd

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Problems in male meiosis resulting in

a male cell with 2 X-chromosomes.

Problems in female meiosis resulting

in a female cell with 2

X-chromosomes.

cases are called 46,XX/47,XXX mosaics.

Symptoms

Because the vast majority of Triple X females are never

diagnosed, it may be very difficult to make generalizations about

the effects of this syndrome. The samples that were studied weresmall and may be nonrepresentative or biased.

Because of the lyonization, inactivation, and formation of Barr

bodies in all female cells, only one X chromosome is active at

any time. Thus, Triple X syndrome most often has only mild

effects, or has no unusual effects at all. Symptoms may include

tall stature; small head (microcephaly); vertical skinfolds that

may cover the inner corners of the eyes (epicanthal folds);

speech and language learning disabilities, such as dyslexia; or

weak muscle tone.[2]The symptoms vary from person to person,

with some women being more affected than others. There are

seldom any observable physical anomalies in Triple X females,

other than being taller than average.

Females with Triple X syndrome are at increased risk of delayed

language development, EEG abnormalities, motor coordination

problems and auditory processing disorders, and scoliosis. They

tend to show accelerated growth until puberty. Premature ovarian

failure seems to be more prevalent in these women, but most Triple X females seem to have normal

fertility. They are more likely to struggle with personality and psychological problems, and low

self-esteem, but these respond well to treatment. Triple X females are at increased risk of poor academic

results at school, and some may need special education. Sometimes, they may suffer from anxiety and be

ery shy, and this may affect their relations with school peers. They seem to feel much better after

leaving school. They benefit very much from a stable home environment.[3]

Incidence

Triple X syndrome occurs in around 1 in 1,000 girls. On average, five to ten girls with triple X syndrome

are born in the United States each day.[4]

First caseThe first published report of a woman with a 47,XXX karyotype was by Patricia A. Jacobs, et al. at

Western General Hospital in Edinburgh, Scotland, in 1959. It was found in a 35-year-old, 5 ft. 9 in.

(176 cm) tall, 128 lb. (58.2 kg) woman who had premature ovarian failure at age 19; her mother was age

41 and her father was 40 at the time of her conception.[5]Jacobs, et al. called the 47,XXX woman a

"superfemale", a term which was immediately criticized, did not gain acceptance, and was based on the


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incorrect assumption that the sex-determination system in mammals was the same as in the fruit fly

Drosophila.[6]British pathologist and geneticist Bernard Lennox, the principal consultant on medical

terms for the Oxford English Dictionary, suggested the term "XXX syndrome".[7]

Diagnosis

The vast majority of Triple X women are never diagnosed, unless they undergo tests for other medicalreasons later in life. Triple X can be diagnosed by a blood test which is able to look at a persons

chromosomes (karyotype).

Triple X syndrome can be diagnosed prenatally through amniocentesis or chorionic villus sampling. In

Denmark, between 1970 and 1984, 76% of the prenatally diagnosed fetuses with triple-X were aborted.

Between 1985-1987, this figure dropped to 56%. With improved information, the number of abortions

diminished. In the Netherlands, between 1991 and 2000, 33% (18/54) of the couples that were

confronted with a prenatal diagnosis of 47,XXX elected to abort. If balanced information is provided to

prospective parents, pre-natally, the incidence of voluntary termination (abortion) is reduced.[8]

See also

Klinefelter syndrome

Turner syndrome

XXXX syndrome

XXXXX syndrome

XYY syndrome

References

Medical text written August 2002 by Contact a Family. Last reviewed February 2008 by Dr R Stanhope,Consultant Paediatric Endocrinologist, Institute of Child Health, London, UK. http://www.cafamily.org.uk/medicalinformation/conditions/azlistings/t40_1.html

1.

http://www.mayoclinic.com/health/triple-x-syndrome/DS01090/DSECTION=symptoms2.http://www.nature.com/ejhg/journal/v18/n3/full/ejhg2009109a.html3.National Library of Medicine (2007). "Genetics Home Reference: Triple X syndrome"(http://ghr.nlm.nih.gov/condition=triplexsyndrome). Retrieved 2007-03-22.

4.

Jacobs, Patricia A.; Baikie, Albert G.; Court Brown, W. Michael; MacGregor, Thomas N.; Maclean, Neil;Harnden, David G. (September 26, 1959). "Evidence for the existence of the human 'super female' ".Lancet274(7100): 423425. doi:10.1016/S0140-6736(59)90415-5 (https://dx.doi.org/10.1016%2FS0140-6736%2859%2990415-5). PMID 14406377 (https://www.ncbi.nlm.nih.gov/pubmed/14406377).

5.

Stern, Curt (December 12, 1959). "Use of the term 'superfemale' ".Lancet274(7111): 1088.doi:10.1016/S0140-6736(59)91557-0 (https://dx.doi.org/10.1016%2FS0140-6736%2859%2991557-0).Jacobs, Patricia A.; Baikie, Albert G.; Court Brown, W. Michael; Harnden, David G.; MacGregor, ThomasN.; Maclean, Neil (December 19, 1959). "Use of the term 'superfemale' ".Lancet274(7112): 1145.doi:10.1016/S0140-6736(59)90132-1 (https://dx.doi.org/10.1016%2FS0140-6736%2859%2990132-1).Jacobs, Patricia A. (March 35, 2006). "The discovery and history of Trisomy X and XYY syndrome".

National Conference on Trisomy X and XYY, UC Davis M.I.N.D. Institute, Sacramento, California. DVD 02.Pine, Colorado: KS&A.Ferguson-Smith, Malcolm A. (December 2009). "It is 50 years since the discovery of the male determining

6.


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role of the Y chromosome!". Sexual Development3(5): 233236. doi:10.1159/000252792 (https://dx.doi.org/10.1159%2F000252792). PMID 19844083 (https://www.ncbi.nlm.nih.gov/pubmed/19844083).Ferguson-Smith, Malcolm A. (September 2011). "Putting medical genetics into practice"(http://www.annualreviews.org/doi/full/10.1146/annurev-genom-082410-101451).Annual Review ofGenomics and Human Genetics 12: 123. doi:10.1146/annurev-genom-082410-101451 (https://dx.doi.org/10.1146%2Fannurev-genom-082410-101451). PMID 21639797 (https://www.ncbi.nlm.nih.gov/pubmed/21639797).Lennox, Bernard (January 2, 1960). "Use of the term 'superfemale' ".Lancet275(7114): 55.

doi:10.1016/S0140-6736(60)92744-6 (https://dx.doi.org/10.1016%2FS0140-6736%2860%2992744-6).Fraser, Jean H.; Campbell, John; MacGillivray, Ronald Charles; Boyd, Elizabeth; Lennox, Bernard(September 17, 1960). "The XXX syndrome: frequency among mental defectives and fertility".Lancet276(7151): 626627. doi:10.1016/S0140-6736(60)91696-2 (https://dx.doi.org/10.1016%2FS0140-6736%2860%2991696-2). PMID 13701513 (https://www.ncbi.nlm.nih.gov/pubmed/13701513).Anderson, John B.; Crofton, John (August 16, 1997). "Obituary: Bernard Lennox"(http://www.accessmylibrary.com/article-1G1-19724979/bernard-lennox-obituary.html). BMJ315(7105):432. doi:10.1136/bmj.315.7105.432 (https://dx.doi.org/10.1136%2Fbmj.315.7105.432).

7.

written by Connie T.R.M. Schrander-Stumpel, MD, PhD, Professor of Clinical Genetics, Academic HospitalMaastricht, Netherlands. http://www.triple-x-syndroom.nl/document31/patient+care+article+triplexsyndrome+or+trisomy+x

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External links

NLM (2008). Triple X syndrome (http://ghr.nlm.nih.gov/condition=triplexsyndrome) Genetics

Home Reference

Guy's Hospital Clinical Genetics Department (2001). Triple X (http://www.bshg.org.uk

/leaflets_forum/leaflets/TripXpro.pdf) information leaflet

Nielsen, Johannes (1998). Triple-X Females. An Orientation (http://www.turnercenteret.dk

/engelsk/triplex.htm). The Turner Center, Aarhus Psychiatric Hospital, Risskov, Denmark.

Triple X information booklet by Dr. Nielsen, a psychiatrist and geneticist who led the

longest running of 8 international newborn screening studies of sex chromosome

abnormalities.

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Categories: Sex chromosome aneuploidies Syndromes

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