Klinefelter's syndrome: Difference between revisions

Jump to navigation Jump to search
VisualWikitext
No edit summary
No edit summary
Line 12: Line 12:
   MeshID        = D007713 |
   MeshID        = D007713 |
}}
}}
{{SI}}
{{Klinefelter's syndrome}}'''For patient information click [[{{PAGENAME}} (patient information)|here]]'''
'''For patient information click [[{{PAGENAME}} (patient information)|here]]'''


:''Not to be confused with [[XYY syndrome]] or [[XXX syndrome]].''
:''Not to be confused with [[XYY syndrome]] or [[XXX syndrome]].''
Line 21: Line 20:
{{SK}} 47XXY; XXY syndrome.
{{SK}} 47XXY; XXY syndrome.


==Overview==
==[[Klinefelter's syndrome overview|Overview]]==


'''Klinefelter's syndrome''' is a condition caused by a [[chromosome]] [[aneuploidy]]. Affected males have an extra [[XY sex-determination system|X sex chromosome]]. The principal effects are development of small [[testicles]] and reduced [[fertility]]. A variety of other physical and behavioral differences and problems are common, though severity varies and many boys and men with the condition have few detectable symptoms. Because of the extra chromosome, individuals with the condition are usually referred to as "XXY Males", or "47, XXY Males".<ref name="orrnichhd1993full">{{cite web |url=http://www.nichd.nih.gov/publications/pubs/klinefelter.cfm |title=Understanding Klinefelter Syndrome: A Guide for XXY Males and Their Families |last=Bock |first=Robert  |accessdate=2007-04-07 |date = 1993 Aug |year = 1993 | month = August |format=HTML |work=NIH Pub. No. 93-3202|publisher=Office of Research Reporting, NICHD}}</ref>
'''Klinefelter's syndrome''' is a condition caused by a [[chromosome]] [[aneuploidy]]. Affected males have an extra [[XY sex-determination system|X sex chromosome]]. The principal effects are development of small [[testicles]] and reduced [[fertility]]. A variety of other physical and behavioral differences and problems are common, though severity varies and many boys and men with the condition have few detectable symptoms. Because of the extra chromosome, individuals with the condition are usually referred to as "XXY Males", or "47, XXY Males".<ref name="orrnichhd1993full">{{cite web |url=http://www.nichd.nih.gov/publications/pubs/klinefelter.cfm |title=Understanding Klinefelter Syndrome: A Guide for XXY Males and Their Families |last=Bock |first=Robert  |accessdate=2007-04-07 |date = 1993 Aug |year = 1993 | month = August |format=HTML |work=NIH Pub. No. 93-3202|publisher=Office of Research Reporting, NICHD}}</ref>


==Historical Perspective==
==[[Klinefelter's syndrome historical perspective|Historical Perspective]]==


It is named after Dr. Harry Klinefelter, an [[endocrinologist]] at [[Massachusetts General Hospital]], Boston, Massachusetts, who first described it in 1942.<ref name="kline1942">{{Citation| last = Klinefelter | first = HF Jr | last2 = Reifenstein | first2 = EC Jr | last3 = Albright | title = Syndrome characterized by gynecomastia, aspermatogenesis without a-Leydigism and increased excretion of follicle-stimulating hormone. | journal = J Clin Endocrinol Metab | volume = 2 | pages = 615–624 | date = 1942 | year = 1942 | pmid = ''too early to be indexed''}}. {{Citation| last = Klinefelter | first = HF | title = Klinefelter's syndrome: historical background and development. | journal = South Med J | volume = 79 | issue = 45| pages = 1089–1093 | date = 1986 | year =1986 | pmid =  3529433}} talks about the history of the development of the literature.</ref>
It is named after Dr. Harry Klinefelter, an [[endocrinologist]] at [[Massachusetts General Hospital]], Boston, Massachusetts, who first described it in 1942.<ref name="kline1942">{{Citation| last = Klinefelter | first = HF Jr | last2 = Reifenstein | first2 = EC Jr | last3 = Albright | title = Syndrome characterized by gynecomastia, aspermatogenesis without a-Leydigism and increased excretion of follicle-stimulating hormone. | journal = J Clin Endocrinol Metab | volume = 2 | pages = 615–624 | date = 1942 | year = 1942 | pmid = ''too early to be indexed''}}. {{Citation| last = Klinefelter | first = HF | title = Klinefelter's syndrome: historical background and development. | journal = South Med J | volume = 79 | issue = 45| pages = 1089–1093 | date = 1986 | year =1986 | pmid =  3529433}} talks about the history of the development of the literature.</ref>
Line 31: Line 30:
The first published report of a man with a 47,XXY karyotype was by Patricia A. Jacobs and Dr. J.A. Strong at [[Western General Hospital]] in Edinburgh, Scotland in 1959.<ref name="nature1959">{{cite journal |author=Jacobs PA, Strong JA |month=January 31, |year=1959 |title=A case of human intersexuality having a possible XXY sex-determining mechanism |journal=[[Nature (journal)|Nature]] |volume=183 |issue=4657 |pages=302–3 |pmid=13632697 |doi= 10.1038/183302a0}}</ref> This karyotype was found in a 24-year-old man who had signs of Klinefelter's syndrome. Dr. Jacobs described her discovery of this first reported human or mammalian chromosome [[aneuploidy]] in her 1981 William Allan Memorial Award address.<ref name="amjhumgenet1982">{{cite journal |author=Jacobs PA |month=September |year=1982 |title=The William Allan Memorial Award address: human population cytogenetics: the first twenty-five years |journal=[[American Journal of Human Genetics|Am J Hum Genet]] |volume=34 |issue=5 |pages=689–98 |pmid=6751075 |url=http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1685430&blobtype=pdf}}</ref>
The first published report of a man with a 47,XXY karyotype was by Patricia A. Jacobs and Dr. J.A. Strong at [[Western General Hospital]] in Edinburgh, Scotland in 1959.<ref name="nature1959">{{cite journal |author=Jacobs PA, Strong JA |month=January 31, |year=1959 |title=A case of human intersexuality having a possible XXY sex-determining mechanism |journal=[[Nature (journal)|Nature]] |volume=183 |issue=4657 |pages=302–3 |pmid=13632697 |doi= 10.1038/183302a0}}</ref> This karyotype was found in a 24-year-old man who had signs of Klinefelter's syndrome. Dr. Jacobs described her discovery of this first reported human or mammalian chromosome [[aneuploidy]] in her 1981 William Allan Memorial Award address.<ref name="amjhumgenet1982">{{cite journal |author=Jacobs PA |month=September |year=1982 |title=The William Allan Memorial Award address: human population cytogenetics: the first twenty-five years |journal=[[American Journal of Human Genetics|Am J Hum Genet]] |volume=34 |issue=5 |pages=689–98 |pmid=6751075 |url=http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1685430&blobtype=pdf}}</ref>


==Pathophysiology==
==[[Klinefelter's syndrome pathophysiology|Pathophysiology]]==


===Genetics===
===Genetics===
Line 50: Line 49:
Medical literature shows some individual case studies of Klinefelter's syndrome coexisting with other disorders, such as [[pulmonary disease]], [[varicose vein]]s, [[diabetes mellitus]], and [[rheumatoid arthritis]], but possible correlations between Klinefelter's and these other conditions are not well characterized or understood.
Medical literature shows some individual case studies of Klinefelter's syndrome coexisting with other disorders, such as [[pulmonary disease]], [[varicose vein]]s, [[diabetes mellitus]], and [[rheumatoid arthritis]], but possible correlations between Klinefelter's and these other conditions are not well characterized or understood.


==Causes==
==[[Klinefelter's syndrome causes|Causes]]==


The extra X chromosome is retained because of a [[Meiosis#Nondisjunction|nondisjunction]] event during [[meiosis]] (sex cell division).
The extra X chromosome is retained because of a [[Meiosis#Nondisjunction|nondisjunction]] event during [[meiosis]] (sex cell division).


==Differentiating Klinefelter's syndrome from other Diseases==
==[[Klinefelter's syndrome differential diagnosis|Differentiating Klinefelter's syndrome from other Diseases]]==


==Epidemiology and Demographics==
==[[Klinefelter's syndrome epidemiology and demographics|Epidemiology and Demographics]]==


It is the second most common extra chromosome condition.  The condition exists in roughly 1 out of every 500 males.<ref name="nihhd2007">{{cite web| title = Klinefelter Syndrome | work = Health Information | publisher = National Institute of Health and Human Development | date = [[2007-02-19]] | url = http://www.nichd.nih.gov/health/topics/klinefelter_syndrome.cfm | format = HTML | accessdate = 2007-03-24 }} and {{cite web | title = Klinefelter syndrome | work = Genetics Home Reference | publisher = National Library of Medicine | year = 2006 | url = http://ghr.nlm.nih.gov/condition%3Dklinefeltersyndrome | format = HTML | accessdate = 2007-03-24 }} both provide statistical estimates.</ref>
It is the second most common extra chromosome condition.  The condition exists in roughly 1 out of every 500 males.<ref name="nihhd2007">{{cite web| title = Klinefelter Syndrome | work = Health Information | publisher = National Institute of Health and Human Development | date = [[2007-02-19]] | url = http://www.nichd.nih.gov/health/topics/klinefelter_syndrome.cfm | format = HTML | accessdate = 2007-03-24 }} and {{cite web | title = Klinefelter syndrome | work = Genetics Home Reference | publisher = National Library of Medicine | year = 2006 | url = http://ghr.nlm.nih.gov/condition%3Dklinefeltersyndrome | format = HTML | accessdate = 2007-03-24 }} both provide statistical estimates.</ref>


==Natural History, Complications and Prognosis==
==[[Klinefelter's syndrome natural history, complications and prognosis|Natural History, Complications and Prognosis]]==


===Complications===
===Complications===
Line 85: Line 84:


==Diagnosis==
==Diagnosis==
 
[[Klinefelter's syndrome history and symptoms|History and Symptoms]] | [[Klinefelter's syndrome physical examination|Physical Examination]] | [[Klinefelter's syndrome laboratory findings|Laboratory findings]]
===History===
===History===


Line 116: Line 115:


==Treatment==
==Treatment==
[[Klinefelter's syndrome medical therapy|Medical Therapy]] | [[Klinefelter's syndrome surgery| Surgery]]


The genetic variation is irreversible, but its symptoms can be altered or treated in a number of ways, including testosterone treatment and other therapies.
The genetic variation is irreversible, but its symptoms can be altered or treated in a number of ways, including testosterone treatment and other therapies.

Revision as of 15:33, 14 August 2012

Klinefelter's syndrome
ICD-10 Q98.0-Q98.4
ICD-9 758.7
DiseasesDB 7189
MedlinePlus 000382
MeSH D007713

Klinefelter's syndrome Microchapters

Home

Patient Information

Overview

Historical Perspective

Pathophysiology

Differentiating Klinefelter's Syndrome from other Diseases

Epidemiology and Demographics

Natural History, Complications and Prognosis

Diagnosis

History and Symptoms

Physical Examination

Laboratory Findings

Treatment

Medical Therapy

Surgery

Klinefelter's syndrome On the Web

Most recent articles

Most cited articles

Review articles

CME Programs

Powerpoint slides

Images

American Roentgen Ray Society Images of Klinefelter's syndrome

All Images
X-rays
Echo & Ultrasound
CT Images
MRI

Ongoing Trials at Clinical Trials.gov

US National Guidelines Clearinghouse

NICE Guidance

FDA on Klinefelter's syndrome

CDC on Klinefelter's syndrome

Klinefelter's syndrome in the news

Blogs on Klinefelter's syndrome

Directions to Hospitals Treating Klinefelter's syndrome

Risk calculators and risk factors for Klinefelter's syndrome

For patient information click here

Not to be confused with XYY syndrome or XXX syndrome.

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Synonyms and keywords: 47XXY; XXY syndrome.

Overview

Klinefelter's syndrome is a condition caused by a chromosome aneuploidy. Affected males have an extra X sex chromosome. The principal effects are development of small testicles and reduced fertility. A variety of other physical and behavioral differences and problems are common, though severity varies and many boys and men with the condition have few detectable symptoms. Because of the extra chromosome, individuals with the condition are usually referred to as "XXY Males", or "47, XXY Males".[1]

Historical Perspective

It is named after Dr. Harry Klinefelter, an endocrinologist at Massachusetts General Hospital, Boston, Massachusetts, who first described it in 1942.[2]

The first published report of a man with a 47,XXY karyotype was by Patricia A. Jacobs and Dr. J.A. Strong at Western General Hospital in Edinburgh, Scotland in 1959.[3] This karyotype was found in a 24-year-old man who had signs of Klinefelter's syndrome. Dr. Jacobs described her discovery of this first reported human or mammalian chromosome aneuploidy in her 1981 William Allan Memorial Award address.[4]

Pathophysiology

Genetics

The extra X chromosome is retained because of a nondisjunction event during meiosis (sex cell division).

In mammals with more than one X chromosome, the genes on all but one X chromosome are not expressed; this is known as X inactivation. This happens in XXY males as well as normal XX females.[5] A few genes located in the pseudoautosomal regions, however, have corresponding genes on the Y chromosome and are capable of being expressed.[6] These triploid genes in XXY males may be responsible for symptoms associated with Klinefelter's syndrome.

It is currently thought that rare X-linked recessive conditions occur even less frequently in XXY males than in normal XY males, since these conditions are transmitted by genes on the X chromosome, and people with two X chromosomes are typically only carriers rather than affected by these X-linked recessive conditions.

Variations

The 48, XXYY (male) syndrome occurs 1 in 17,000 births and has traditionally been considered to be a variation of Klinefelter's syndrome. XXYY is no longer generally considered a variation of KS, although it has not yet been assigned an ICD-9 code.

Males with Klinefelter syndrome may have a mosaic 47,XXY/46,XY constitutional karyotype and varying degrees of spermatogenic failure. Mosaicism 47,XXY/46,XX with clinical features suggestive of Klinefelter syndrome is very rare. Thus far, only about 10 cases have been described in literature.[7]

Associated Conditions

Medical literature shows some individual case studies of Klinefelter's syndrome coexisting with other disorders, such as pulmonary disease, varicose veins, diabetes mellitus, and rheumatoid arthritis, but possible correlations between Klinefelter's and these other conditions are not well characterized or understood.

Causes

The extra X chromosome is retained because of a nondisjunction event during meiosis (sex cell division).

Differentiating Klinefelter's syndrome from other Diseases

Epidemiology and Demographics

It is the second most common extra chromosome condition. The condition exists in roughly 1 out of every 500 males.[8]

Natural History, Complications and Prognosis

Complications

In these patients, GSTs usually contain nonseminomatous elements, present at an earlier age, and seldom are testicular in location.

The syndrome increases the risk of:

Enlarged teeth with a thinning surface (taurodontism) is very common in Klinefelter's syndrome. It can be diagnosed by dental x-rays.

Prognosis

  • Most patients have a normal, productive life.

Diagnosis

History and Symptoms | Physical Examination | Laboratory findings

History

Symptoms

  • Affected males are almost always effectively sterile, although advanced reproductive assistance is sometimes possible.[10]
  • Some degree of language learning impairment may be present,[11] and neuropsychological testing often reveals deficits in executive functions[12].
  • In adults, possible characteristics vary widely and include little to no signs of affectedness, a lanky, youthful build and facial appearance, or a rounded body type with some degree of gynecomastia (increased breast tissue).[13]
  • Gynecomastia is present to some extent in about a third of affected individuals, a slightly higher percentage than in the XY population, but only about 10% of XXY males' gynecomastia is noticeable enough to require surgery.[14]
  • There are many variances within the XXY population, just as in the most common 46,XY population. While it is possible to characterise 47,XXY males with certain body types, that in itself should not be the method of identification as to whether or not someone has 47,XXY. The only reliable method of identification is karyotype testing.

Physical Examination

  • In adults, possible characteristics vary widely and include little to no signs of affectedness, a lanky, youthful build and facial appearance, or a rounded body type with some degree of gynecomastia (increased breast tissue).[13]
  • Gynecomastia is present to some extent in about a third of affected individuals, a slightly higher percentage than in the XY population, but only about 10% of XXY males' gynecomastia is noticeable enough to require surgery.[14]
  • There are many variances within the XXY population, just as in the most common 46,XY population. While it is possible to characterise 47,XXY males with certain body types, that in itself should not be the method of identification as to whether or not someone has 47,XXY. The only reliable method of identification is karyotype testing.
  • Hypogonadism in XXY symptoms is often misinterpreted to mean "small testicles" or "small penis". In fact, it means decreased testicular hormone/endocrine function. Because of this hypogonadism, patients will often have a low serum testosterone level but high serum follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels.[15] Despite this misunderstanding of the term, however, it is true that XXY men often also have "microorchidism" (i.e. small testicles).[15]

Laboratory Findings

A karyotype is used to confirm the diagnosis. In this procedure, a small blood sample is drawn. White blood cells are then separated from the sample, mixed with tissue culture medium, incubated, and checked for chromosomal abnormalities, such as an extra X chromosome.

The following tests may be performed:

Treatment

Medical Therapy | Surgery

The genetic variation is irreversible, but its symptoms can be altered or treated in a number of ways, including testosterone treatment and other therapies.

Testosterone therapy may be prescribed. This can help:

Most men with this syndrome are not able to father children. However, some men have been able to have children. An infertility specialist may be able to help.

Inadequately treated hypogonadism in Klinefelter syndrome increases recognized psychosocial morbidity.[16] At least one study indicates that planned and timed support should be provided for young men with Klinefelter syndrome, to ameliorate current poor psychosocial outcomes.[16]

References

  1. ↑ Bock, Robert (1993 Aug). "Understanding Klinefelter Syndrome: A Guide for XXY Males and Their Families" (HTML). NIH Pub. No. 93-3202. Office of Research Reporting, NICHD. Retrieved 2007-04-07. Unknown parameter |month= ignored (help); Check date values in: |date= (help)
  2. ↑ Klinefelter, HF Jr; Reifenstein, EC Jr; Albright (1942), "Syndrome characterized by gynecomastia, aspermatogenesis without a-Leydigism and increased excretion of follicle-stimulating hormone.", J Clin Endocrinol Metab, 2: 615–624, PMID too early to be indexed ''too early to be indexed'' Check |pmid= value (help). Klinefelter, HF (1986), "Klinefelter's syndrome: historical background and development.", South Med J, 79 (45): 1089–1093, PMID 3529433 talks about the history of the development of the literature.
  3. ↑ Jacobs PA, Strong JA (1959). "A case of human intersexuality having a possible XXY sex-determining mechanism". Nature. 183 (4657): 302–3. doi:10.1038/183302a0. PMID 13632697. Unknown parameter |month= ignored (help)
  4. ↑ Jacobs PA (1982). "The William Allan Memorial Award address: human population cytogenetics: the first twenty-five years". Am J Hum Genet. 34 (5): 689–98. PMID 6751075. Unknown parameter |month= ignored (help)
  5. ↑ Chow J, Yen Z, Ziesche S, Brown C (2005). "Silencing of the mammalian X chromosome". Annu Rev Genomics Hum Genet 6: 69-92. PMID 16124854
  6. ↑ Blaschke RJ, Rappold G (2006). The pseudoautosomal regions, SHOX and disease. Curr Opin Genet Dev. Jun; 16:233-9. PMID 16650979
  7. ↑ Velissariou V, Christopoulou S, Karadimas C, Pihos I, Kanaka-Gantenbein C, Kapranos N, Kallipolitis G, Hatzaki A. "Rare XXY/XX mosaicism in a phenotypic male with Klinefelter syndrome: case report". Eur J Med Genet 2006 July - August;49(4):331-337. PMID 16829354
  8. ↑ "Klinefelter Syndrome" (HTML). Health Information. National Institute of Health and Human Development. 2007-02-19. Retrieved 2007-03-24. Check date values in: |date= (help) and "Klinefelter syndrome" (HTML). Genetics Home Reference. National Library of Medicine. 2006. Retrieved 2007-03-24. both provide statistical estimates.
  9. ↑ Mediastinal germ cell tumor in a child with precocious puberty and Klinefelter syndrome. Gregory G. Bebb, Frederic W. Grannis, Jr, Isaac B. Paz, Marilyn L. Slovak, Robert Chilcote. Ann Thorac Surg 1998;66:547-548. [http://ats.ctsnetjournals.org/cgi/content/abstract/66/2/547 Online}
  10. ↑ Denschlag, Dominik, MD; Clemens, Tempfer, MD; Kunze, Myriam, MD; Wolff, Gerhard, MD; Keck, Christoph, MD (October 2004), "Assisted reproductive techniques in patients with Klinefelter syndrome: A critical review", Fertility and Sterility, 82 (4): 775–779, doi:10.1016/j.fertnstert.2003.09.085
  11. ↑ Graham, JM Jr; Bashir, AS; Stark, RE; Silbert, A; Walzer, S (June 1988), "Oral and written language abilities of XXY boys: implications for anticipatory guidance.", Pediatrics, 81 (6): 795–806, PMID 3368277
  12. ↑ Boone et al: (2001), "Neuropsychological profiles of adults with Klinefelter syndrome" in Journal of International Neuropsychological Society, #7, p 446-456.
  13. ↑ 13.0 13.1 Abstract of Klinefelter, HF (1986), "Klinefelter's syndrome: historical background and development.", South Med J, 79 (9): 1089–1093, PMID 3529433 provides information on microorchidism (small testes), hypogonadism (infertility/sterility and androgen hormone function) and gynecomastia. Bock, Robert (1993 Aug). "Understanding Klinefelter Syndrome: A Guide for XXY Males and Their Families" (HTML). NIH Pub. No. 93-3202. Office of Research Reporting, NICHD. Retrieved 2007-03-28. Unknown parameter |month= ignored (help); Check date values in: |date= (help) offers substantive information about body type and appearance until a more rigorous source is found/supplied.
  14. ↑ 14.0 14.1 Bock, Robert (1993 Aug). "Understanding Klinefelter Syndrome: A Guide for XXY Males and Their Families, Adolescence section" (HTML). NIH Pub. No. 93-3202. Office of Research Reporting, NICHD. Retrieved 2007-03-29. Unknown parameter |month= ignored (help); Check date values in: |date= (help) describes statistical occurrence of gynecomastia and surgical treatment.
  15. ↑ 15.0 15.1 Leask, Kathryn (October 2005). "Klinefelter syndrome" (HTML). National Library for Health, Specialist Libraries, Clinical Genetics. National Library for Health. Retrieved 2007-04-07.
  16. ↑ 16.0 16.1 Simm PJ, Zacharin MR. "The psychosocial impact of Klinefelter syndrome--a 10 year review". J Pediatr Endocrinol Metab 2006 Apr;19(4):499-505. PMID 16759035

Related Chapters

Template:Chromosomal abnormalities

cs:Klinefelterův syndrom da:Klinefelters syndrom de:Klinefelter-Syndrom it:Sindrome di Klinefelter he:תסמונת קליינפלטר hu:Klinefelter-szindróma nl:Syndroom van Klinefelter no:Klinefelter syndrom sr:Клинефелтеров синдром fi:Klinefelterin syndrooma sv:Klinefelters syndrom

Template:WikiDoc Sources

Retrieved from "https://www.wikidoc.org/index.php?title=Klinefelter%27s_syndrome&oldid=683314"