Common tests & procedures
The doctor will look at the chromosomes to check for an extra X chromosome. Looking at someone’s chromosomes is done by a blood test called karyotype. This test can confirm a diagnosis of Klinefelter syndrome because there are 47 chromosomes, including two X chromosomes and a Y. This can be done in children, adults and even in a baby before birth.
How is Klinefelter syndrome diagnosed?
If the sperm holds a Y chromosome when it meets the egg, the resulting baby will be a male (46, XY). Klinefelter syndrome happens when there is an extra X chromosome in the genetic code. This change happens before birth and can happen in a few different ways.
How does Klinefelter syndrome affect the sex of a baby?
Klinefelter syndrome is fairly common, happening in about 1 in 600 males, but many men (some say 70 to 80%) likely do not know they have this condition. What causes Klinefelter syndrome? Typically, a person’s genetic code is made up of either two X chromosomes (genetic female) or one X and one Y chromosome (genetic male).
How common is Klinefelter syndrome?
The earlier a diagnosis is made and treatment is started, the greater the benefits. But it's never too late to get help. Treatment for Klinefelter syndrome is based on signs and symptoms and may include: Testosterone replacement therapy.
Is it too late to get help for Klinefelter syndrome?
Can Klinefelter syndrome be detected in ultrasound?
Klinefelter syndrome (KS), a common sex chromosome aneuploidy (47,XXY) is diagnosed prenatally with an incidence of 0.15%. The diagnosis is generally incidental, since there are no typical malformations on ultrasound (US).
When can Klinefelter syndrome be detected?
Klinefelter syndrome usually is not diagnosed until the time of puberty. At this point, the boy's testicles fail to grow, and you may start to notice other symptoms.
Can Klinefelter syndrome go undetected?
Many boys with Klinefelter syndrome show few or only mild signs. The condition may go undiagnosed until adulthood or it may never be diagnosed. For others, the condition has a noticeable effect on growth or appearance.
What are the chances of having a child with Klinefelter syndrome?
Prevalence of Klinefelter syndrome variantsNumber of extra X chromosomesOne (XXY)Three (XXXXY)Number of newborn males with the condition1 in 5001 in 85,000 to 100,000Dec 1, 2016
Who is most likely to get Klinefelter's syndrome?
This is written as XXY. Klinefelter syndrome occurs in about 1 out of 500 to 1,000 baby boys. Women who get pregnant after age 35 are slightly more likely to have a boy with this syndrome than younger women.
How do I know if my child has Klinefelter syndrome?
Babies with Klinefelter syndrome typically have weak muscles, reduced strength, and quiet personalities. They also can take longer to do things like sit up, crawl, walk, and speak. Compared with other kids their age, boys with Klinefelter syndrome might have some or all of these symptoms: a taller, less muscular body.
Why is Klinefelter so tall?
From early school age, boys with Klinefelter syndrome tend to be taller (increased leg length) in part because testosterone (via conversion to oestrogen) normally stops the long bones from growing after puberty. This increase in height is maintained throughout life.
Are all Klinefelter's infertile?
Between 95% and 99% of XXY men are infertile because they do not produce enough sperm to fertilize an egg naturally. But, sperm are found in more than 50% of men with KS.
Are all people with Klinefelter syndrome tall?
Adults with Klinefelter syndrome are usually taller than nonaffected adult males, reaching a mean final height of about 185 cm (73 in). XXY males (see the image below) also have disproportionately long arms and legs. About 25% of patients have fifth-finger clinodactyly.
Which parent is responsible for Klinefelter's syndrome?
Klinefelter syndrome is not directly inherited – the additional X chromosome occurs as a result of either the mother's egg or the father's sperm having the extra X chromosome (an equal chance of this happening in either), so after conception the chromosome pattern is XXY rather than XY.
How is Klinefelter syndrome diagnosed?
Blood or urine samples can reveal abnormal hormone levels that are a sign of Klinefelter syndrome. Chromosome analysis. Also called karyotype analysis, this test is used to confirm a diagnosis of Klinefelter syndrome. A blood sample is sent to the lab to check the shape and number of chromosomes.
Are all Klinefelter's infertile?
Between 95% and 99% of XXY men are infertile because they do not produce enough sperm to fertilize an egg naturally. But, sperm are found in more than 50% of men with KS.
How long can a person live with Klinefelter's syndrome?
Prognosis for Klinefelter Syndrome In general, life expectancy is normal. Some research has found that life expectancy for men with the condition may be a year or two less than those without it because of other health problems linked to Klinefelter.
How frequently does Klinefelter syndrome occur?
The presence of a Y chromosome denotes male sex. Boys and men with Klinefelter syndrome are still genetically male, and often will not realise they have this extra chromosome, but occasionally it can cause problems that may require treatment. Klinefelter syndrome affects around 1 in every 660 males.
When is Klinefelter syndrome diagnosed?
A small percentage of males with Klinefelter syndrome are diagnosed before birth. The syndrome might be identified in pregnancy during a procedure to examine fetal cells drawn from the amniotic fluid (amniocentesis) or placenta for another reason — such as being older than age 35 or having a family history of genetic conditions.
What test is used to diagnose Klinefelter syndrome?
The main tests used to diagnose Klinefelter syndrome are: Hormone testing. Blood or urine samples can reveal abnormal hormone levels that are a sign of Klinefelter syndrome. Chromosome analysis. Also called karyotype analysis, this test is used to confirm a diagnosis of Klinefelter syndrome. A blood sample is sent to the lab to check ...
How to help a boy with Klinefelter syndrome?
Educational evaluation and support. Some boys with Klinefelter syndrome have trouble learning and socializing and can benefit from extra assistance. Talk to your child's teacher, school counselor or school nurse about what kind of support might help.
What kind of doctor treats Klinefelter syndrome?
If you or your son is diagnosed with Klinefelter syndrome, your health care team may include a doctor who specializes in diagnosing and treating disorders involving the body's glands and hormones (endocrinologist), a speech therapist, a pediatrician, a physical therapist, a genetic counselor, a reproductive medicine or infertility specialist, and a counselor or psychologist .
Is it too late to get help for Klinefelter syndrome?
The earlier a diagnosis is made and treatment is started, the greater the benefits. But it's never too late to get help. Treatment for Klinefelter syndrome is based on signs and symptoms and may include: Testosterone replacement therapy. Starting at the time of the usual onset of puberty, testosterone replacement therapy can be given ...
Can Klinefelter syndrome be detected during a blood test?
Klinefelter syndrome may be suspected during a noninvasive prenatal screening blood test. To confirm the diagnosis, further invasive prenatal testing such as amniocentesis is required.
What Is Klinefelter Syndrome?
When we focus on the sex chromosomes, we see that typically women have two X chromosomes and men have an X and a Y chromosome.
When was Klinefelter syndrome first described?
A list of references is also included at the bottom of this article. The first medical description of Klinefelter syndrome was in 1942. Since that time, doctors and researchers have come to learn it’s the most common chromosomal abnormality affecting newborn males.
What tests are used to test for Klinefelter syndrome?
Laboratory Testing for Klinefelter Syndrome. In addition to genetic testing, hormone tests can also be used to measure various hormone levels, including testosterone. Individuals with Klinefelter Syndrome will have low levels of testosterone.
How long does a person with Klinefelter syndrome live?
Analysis of 25 years of studies involving 466 men with Klinefelter syndrome found that patients had a 50% higher mortality rate 3 and their life expectancy was 5 years shorter than average. However, more recent research estimates that life expectancy is shortened by only 2 years 4.
How long does it take for Klinefelter syndrome to go undiagnosed?
For most individuals with Klinefelter Syndrome, the signs and symptoms tend to be mild, often going undiagnosed until puberty or adulthood. This is because the most common symptom associated with this condition is infertility, occuring in 90% of cases.
What percentage of children with Klinefelter syndrome have a learning disability?
Upwards of 75% of children with it have a learning disability. Boys with Klinefelter syndrome may also have difficulty fitting in socially and interacting with their peers as personality traits often include being shy and quiet.
What is the risk of getting a fracture in a boy?
Fractures are another regular occurrence due to weakened bones (osteoporosis). Boys and men with Klinefelter syndrome have a 2-40 fold increased risk of getting a bone fracture. Additionally, individuals are at an increased risk for breast cancer, lung disease, and varicose veins.
What is the first sign of a child with Klinefelter syndrome?
In young children, the first sign is often a delay in speaking or learning. For example, a baby with Klinefelter syndrome might speak later than his peers.
Why is Klinefelter syndrome not discovered?
Because these tests can increase the risk for a miscarriage, they usually aren’t done unless the baby is at risk for a chromosome problem. Often Klinefelter syndrome isn’t discovered until a boy reaches puberty or later. If your child is slow to develop, see an endocrinologist.
What is the genetic condition that causes males to be born with an extra copy of the X chromosome?
Klinefelter syndrome is a genetic disease that causes males to be born with an extra copy of the X chromosome in their cells. Males with this condition have smaller-than-normal testicles that produce less testosterone. Testosterone is the male hormone that stimulates sexual traits like body hair and muscle growth.
Why do boys with Klinefelter syndrome not notice symptoms?
Because most of the symptoms stem from low testosterone, many boys with Klinefelter syndrome don’t notice any symptoms until they reach puberty. That’s when testosterone levels normally increase.
What tests are used to diagnose Klinefelter syndrome?
Two types of tests are used to diagnose Klinefelter syndrome: Chromosome analysis: Also called karyotyping, this blood test checks for abnormal chromosomes, such as an extra X chromosome. Hormone testing: Blood or urine tests can show low testosterone levels, which are a sign of Klinefelter syndrome.
How many babies does Klinefelter affect?
It affects between 1 in 500 and 1 in 1,000 newborn males. Variants of the disease with three, four, or more extra X chromosomes are less common. These variants affect 1 in 50,000 or fewer newborns. It’s possible that Klinefelter syndrome affects even more boys and men than statistics suggest.
How often can you get Klinefelter syndrome?
Or you can get it by injection every two to three weeks. Other treatments for Klinefelter syndrome include: speech and language therapy. physical therapy to improve muscle strength. occupational therapy to help you function day to day at school, work, and in your social life.
What are the symptoms of Klinefelter syndrome?
Individuals with Klinefelter syndrome tend to have anxiety, depression, impaired social skills, behavioral problems such as emotional immaturity and impulsivity, attention-deficit/hyperactivity disorder (ADHD), and limited problem-solving skills (executive functioning). About 10 percent of boys and men with Klinefelter syndrome have autism spectrum ...
What are the conditions that Klinefelter syndrome causes?
Nearly half of all men with Klinefelter syndrome develop metabolic syndrome, which is a group of conditions that include type 2 diabetes, high blood pressure ( hypertension ), increased belly fat, high levels of fats (lipids) such as cholesterol and triglycerides in the blood.
What are the physical changes associated with Klinefelter syndrome?
Other physical changes associated with Klinefelter syndrome are usually subtle. Older children and adults with the condition tend to be somewhat taller than their peers. Other differences can include abnormal fusion of certain bones in the forearm (radioulnar synostosis), curved pinky fingers (fifth finger clinodactyly ), ...
What is the collapsing section of Klinefelter syndrome?
Description. Collapse Section. Klinefelter syndrome is a chromosomal condition in boys and men that can affect physical and intellectual development. Most commonly, affected individuals are taller than average are unable to father biological children (infertile); however the signs and symptoms of Klinefelter syndrome vary among boys ...
What percentage of people with Klinefelter syndrome have mosaic?
It is thought that less than 10 percent of individuals with Klinefelter syndrome have the mosaic form. Boys and men with mosaic Klinefelter syndrome may have milder signs and symptoms than those with the extra X chromosome in all of their cells, depending on what proportion of cells have the additional chromosome.
What is the difference between Klinefelter syndrome and expressive language?
Boys and men with Klinefelter syndrome tend to have better receptive language skills (the ability to understand speech) than expressive language skills (vocabulary and the production of speech) and may have difficulty communicating and expressing themselves.
What hormones are produced by Klinefelter syndrome?
Boys and men with Klinefelter syndrome typically have small testes that produce a reduced amount of testosterone (primary testicular insufficiency). Testosterone is the hormone that directs male sexual development before birth and during puberty. Without treatment, the shortage of testosterone can lead to delayed or incomplete puberty, ...
