Klinefelter Syndrome: Difference between revisions
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== | == Introduction<br> == | ||
Klinefelter syndrome is a genetic condition that results when a boy is born with an extra copy of the X chromosome. Klinefelter syndrome is a genetic condition affecting males, and it often isn't diagnosed until adulthood. | |||
Klinefelter syndrome may adversely affect testicular growth, resulting in smaller than normal testicles, which can lead to lower production of testosterone. The syndrome may also cause reduced muscle mass, reduced body and facial hair, and enlarged breast tissue. The effects of Klinefelter syndrome vary, and not everyone has the same signs and symptoms. | |||
Most men with Klinefelter syndrome produce little or no sperm, but assisted reproductive procedures may make it possible for some men with Klinefelter syndrome to father children. | |||
== Causes<br> == | |||
Klinefelter syndrome occurs as a result of a random error that causes a male to be born with an extra sex chromosome. [[It isn't an inherited condition.]] | |||
Most often, Klinefelter syndrome is caused by a single extra copy of the X chromosome, resulting in a total of 47 chromosomes per cell. Males normally have one X chromosome and one Y chromosome in each cell (46, XY), while females have two X chromosomes (46, XX). | |||
- An error in cell division called nondisjunction results in a reproductive cell with an abnormal number of chromosomes. For example, an egg or sperm cell may gain one or more extra copies of the X chromosome as a result of [[nondisjunction]]. If one of these atypical reproductive cells contributes to the genetic makeup of a child, the child will have one extra copy of the X chromosome in each cell (XXY), the most common cause, or more extra X chromosomes in each of the body's cells which is rare and known as "variants of Klinefelter syndrome(48,XXXY, 48,XXYY and 49,XXXXY) and results in a severe form . | |||
- People with Klinefelter syndrome usually have two X chromosomes and one Y chromosome (47, XXY). Some people with Klinefelter syndrome have the extra X chromosome in only some of their cells; these people are said to have [[mosaic]] Klinefelter syndrome, with fewer symptoms. | |||
It is estimated that about half of the time, the cell division error occurs during development of the sperm, while the remainder are due to errors in egg development. Women who have pregnancies after age 35 have a slightly increased chance of having offspring with this syndrome. | |||
== Incidence == | |||
It is estimated that 1 in every 500 to 1,000 newborn males has an extra X chromosome, making Klinefelter syndrome one of the most common chromosomal disorders seen among newborns. Variants of Klinefelter syndrome (such as 48,XXXY, 49,XXXXY) are much rarer, occurring in 1 in 50,000 to 1 in 85,000 or fewer newborns. | |||
== Other Medical or Scientific Names == | |||
- 47,XXY | |||
- XXY syndrome or condition | |||
- XXY trisomy | |||
- 47,XXY/46,XY or mosaic syndrome (rare variation) | |||
- Poly-X Klinefelter syndrome, including the following rare variations: | |||
* 48,XXYY (or tetrasomy) | |||
* 48,XXXY (or tetrasomy) | |||
*49,XXXXY (or pentasomy) | |||
== Signs and Symptoms == | |||
The signs and symptoms vary among affected people. Some men with KS have no symptoms of the condition or are only mildy affected. In these cases, they may not even know that they are affected by KS. When present, symptoms may include:[1][2][3] | |||
Small, firm testicles | |||
Delayed or incomplete puberty with lack of secondary sexual characteristics resulting in sparse facial, body, or sexual hair a high-pitched voice and body fat distribution resulting in a rounder, lower half of the body, with more fat deposited in the hips, buttocks and thigh instead of around the chest and abdomen | |||
Breast growth (gynecomastia) | |||
Reduced facial and body hair | |||
Infertility | |||
Tall stature | |||
Abnormal body proportions (long legs, short trunk, shoulder equal to hip size) | |||
Learning disablity | |||
Speech delay | |||
Crypthochirdism | |||
Opening (meatus) of the urethra (the tube that carries urine and sperm through the penis to the outside) on the underside of the penis (hypospadias) instead of the tip of the head of the penis | |||
Social, psychologic and behavioral problems | |||
Whether or not a male with KS has visible symptoms depends on many factors, including how much testosterone his body makes, if he is mosaic (with both XY and XXY cells), and his age when the condition is diagnosed and treated.[1] Some people have a slightly increased risk of developing breast cancer, a rare extragonadal germ cell tumor, lung disease, varicose veins and osteoporosis as well as some autoimmune disorders such as systemic lupus erythematosus, rheumatoid arthritis and Sjogren's syndrome.[2][4] | |||
Some people with features of Klinefelter syndrome have more than one extra X chromosome in each cell (such as 48,XXXY or 49,XXXXY). In these cases, known as "variants of Klinefelter syndrome", the signs and symptoms can be more severe and may include:[1][2][4] | |||
Intellectual disability | |||
Distinctive facial features | |||
Skeletal abnormalities | |||
Poor coordination | |||
Severe speech difficulties | |||
Behavioral problems | |||
Heart defects | |||
Teeth problems. | |||
<br> | |||
== Diagnostic Procedures == | == Diagnostic Procedures == | ||
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== References == | == References == | ||
Myśliwiec, Andrzej & Knapik, Henryk & Pasek, Angelika & Kuszewski, Michał & Saulicz, Mariola & Ryngier, Paweł & Wolny, Tomasz. (2011). REHABILITATION OF PATIENTS WITH THE KLINEFELTER’S SYNDROME - REVIEW OF AVAILABLE LITERATURE. | |||
https://rarediseases.info.nih.gov/diseases/8705/klinefelter-syndrome#ref_846 | |||
https://www.nichd.nih.gov/health/topics/klinefelter | |||
https://www.ncbi.nlm.nih.gov/gtr/conditions/C0022735/?_ga=2.249310535.1187197716.1601932924-37510577.1601932924 | |||
https://www.youtube.com/watch?v=R-jqm7KXd0s&has_verified=1 |
Revision as of 00:42, 6 October 2020
Introduction
[edit | edit source]
Klinefelter syndrome is a genetic condition that results when a boy is born with an extra copy of the X chromosome. Klinefelter syndrome is a genetic condition affecting males, and it often isn't diagnosed until adulthood.
Klinefelter syndrome may adversely affect testicular growth, resulting in smaller than normal testicles, which can lead to lower production of testosterone. The syndrome may also cause reduced muscle mass, reduced body and facial hair, and enlarged breast tissue. The effects of Klinefelter syndrome vary, and not everyone has the same signs and symptoms.
Most men with Klinefelter syndrome produce little or no sperm, but assisted reproductive procedures may make it possible for some men with Klinefelter syndrome to father children.
Causes
[edit | edit source]
Klinefelter syndrome occurs as a result of a random error that causes a male to be born with an extra sex chromosome. It isn't an inherited condition.
Most often, Klinefelter syndrome is caused by a single extra copy of the X chromosome, resulting in a total of 47 chromosomes per cell. Males normally have one X chromosome and one Y chromosome in each cell (46, XY), while females have two X chromosomes (46, XX).
- An error in cell division called nondisjunction results in a reproductive cell with an abnormal number of chromosomes. For example, an egg or sperm cell may gain one or more extra copies of the X chromosome as a result of nondisjunction. If one of these atypical reproductive cells contributes to the genetic makeup of a child, the child will have one extra copy of the X chromosome in each cell (XXY), the most common cause, or more extra X chromosomes in each of the body's cells which is rare and known as "variants of Klinefelter syndrome(48,XXXY, 48,XXYY and 49,XXXXY) and results in a severe form .
- People with Klinefelter syndrome usually have two X chromosomes and one Y chromosome (47, XXY). Some people with Klinefelter syndrome have the extra X chromosome in only some of their cells; these people are said to have mosaic Klinefelter syndrome, with fewer symptoms.
It is estimated that about half of the time, the cell division error occurs during development of the sperm, while the remainder are due to errors in egg development. Women who have pregnancies after age 35 have a slightly increased chance of having offspring with this syndrome.
Incidence[edit | edit source]
It is estimated that 1 in every 500 to 1,000 newborn males has an extra X chromosome, making Klinefelter syndrome one of the most common chromosomal disorders seen among newborns. Variants of Klinefelter syndrome (such as 48,XXXY, 49,XXXXY) are much rarer, occurring in 1 in 50,000 to 1 in 85,000 or fewer newborns.
Other Medical or Scientific Names[edit | edit source]
- 47,XXY - XXY syndrome or condition - XXY trisomy - 47,XXY/46,XY or mosaic syndrome (rare variation) - Poly-X Klinefelter syndrome, including the following rare variations: * 48,XXYY (or tetrasomy) * 48,XXXY (or tetrasomy) *49,XXXXY (or pentasomy)
Signs and Symptoms[edit | edit source]
The signs and symptoms vary among affected people. Some men with KS have no symptoms of the condition or are only mildy affected. In these cases, they may not even know that they are affected by KS. When present, symptoms may include:[1][2][3]
Small, firm testicles Delayed or incomplete puberty with lack of secondary sexual characteristics resulting in sparse facial, body, or sexual hair a high-pitched voice and body fat distribution resulting in a rounder, lower half of the body, with more fat deposited in the hips, buttocks and thigh instead of around the chest and abdomen Breast growth (gynecomastia) Reduced facial and body hair Infertility Tall stature Abnormal body proportions (long legs, short trunk, shoulder equal to hip size) Learning disablity Speech delay Crypthochirdism Opening (meatus) of the urethra (the tube that carries urine and sperm through the penis to the outside) on the underside of the penis (hypospadias) instead of the tip of the head of the penis Social, psychologic and behavioral problems
Whether or not a male with KS has visible symptoms depends on many factors, including how much testosterone his body makes, if he is mosaic (with both XY and XXY cells), and his age when the condition is diagnosed and treated.[1] Some people have a slightly increased risk of developing breast cancer, a rare extragonadal germ cell tumor, lung disease, varicose veins and osteoporosis as well as some autoimmune disorders such as systemic lupus erythematosus, rheumatoid arthritis and Sjogren's syndrome.[2][4]
Some people with features of Klinefelter syndrome have more than one extra X chromosome in each cell (such as 48,XXXY or 49,XXXXY). In these cases, known as "variants of Klinefelter syndrome", the signs and symptoms can be more severe and may include:[1][2][4]
Intellectual disability Distinctive facial features Skeletal abnormalities Poor coordination Severe speech difficulties Behavioral problems Heart defects Teeth problems.
Diagnostic Procedures[edit | edit source]
add text here relating to diagnostic tests for the condition
Outcome Measures[edit | edit source]
add links to outcome measures here (see Outcome Measures Database)
Management / Interventions
[edit | edit source]
add text here relating to management approaches to the condition
Differential Diagnosis
[edit | edit source]
add text here relating to the differential diagnosis of this condition
Resources
[edit | edit source]
add appropriate resources here
References[edit | edit source]
Myśliwiec, Andrzej & Knapik, Henryk & Pasek, Angelika & Kuszewski, Michał & Saulicz, Mariola & Ryngier, Paweł & Wolny, Tomasz. (2011). REHABILITATION OF PATIENTS WITH THE KLINEFELTER’S SYNDROME - REVIEW OF AVAILABLE LITERATURE.
https://rarediseases.info.nih.gov/diseases/8705/klinefelter-syndrome#ref_846