March 12, 2025 • 10 mins
Klinefelter Syndrome: Have you ever wondered about the nuances of genetic conditions that often fly under the radar? What is it? What are the symptoms? What causes it? Explore its fascinating history, discover the symptoms, and learn about the effective treatment and management options available. You might be surprised by just how common this condition is. Tune in to learn more!
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Resources:
People with Klinefelter Syndrome: https://livingwithxxy.org/blog/
American association For X and Y chromosome variations: https://genetic.org/
Klinefelter Syndrome Association (UK): https://www.ksa-uk.net/
References:
https://www.anu.edu.au/news/all-news/oldest-case-of-a-rare-genetic-condition-discovered
https://www.nichd.nih.gov/health/topics/klinefelter/conditioninfo
https://www.fertstert.org/article/S0015-0282(12)00654-1/pdf
https://www.healthdirect.gov.au/gynaecomastia
https://my.clevelandclinic.org/health/diseases/15441-azoospermia
https://www.mayoclinic.org/diseases-conditions/klinefelter-syndrome/symptoms-causes/syc-20353949
https://my.clevelandclinic.org/health/diseases/21116-klinefelter-syndrome
https://sangerinstitute.blog/2022/05/17/six-unbelievable-things-you-probably-didnt-know-about-dna/
https://www.mayoclinic.org/tests-procedures/amniocentesis/about/pac-20392914
https://medlineplus.gov/genetics/condition/klinefelter-syndrome/
*This podcast is for entertainment purposes only. If you suspect you have a medical condition, please seek out an opinion of a medical professional.*
Mark as Played
Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
(00:00):
Recently, your son Jack turned 15.
(00:03):
Although he has always been tall for his age, you can't help but notice he looks much
younger than his peers.
His friends are starting to sport facial hair and develop more muscular builds, while Jack
remains significantly skinnier and devoid of any facial hair.
It's not just his appearance that raises concerns.
You've noticed that he seems less confident in social situations, often shying away from
(00:24):
activities that involve his peers, which raises concerns about his health and his well-being.
Worried about his growth and development?
You decide to take him to a doctor for a thorough check-up.
(00:49):
Hello and welcome to Anatomy Of Illness.
Today's episode is about Klinefelter Syndrome.
Before we get into the condition, we are going to start with the history.
So why do we know Klinefelter Syndrome exists?
If you have been with us for a while and think we are worth five stars, don't forget to leave
us a review and share with a friend.
We begin around 1,000 years ago, over in Portugal.
There was a skeleton found in Portugal, specifically the Tor Velha archaeological site.
(01:12):
When its DNA was assessed, it was found to have the genetics of Klinefelter Syndrome.
Now we are going to jump forward to 1942.
This is where we meet Harry Klinefelter.
Dr. Klinefelter would describe the cases of nine men with gynaecomastia, small testes,
and azoospermia.
Gynaecomastia is an increase in breast tissue in men.
Azoospermia is a lack of sperm.
(01:32):
Now we move to 1959, as this is where we would finally understand the cause of Klinefelter
Syndrome.
This is where a study would first demonstrate men with the condition would have an extra
X chromosome.
So rather than being XY, they would be XXY.
I know, a short history, however, this disease has not been very well researched.
Ow!
Something just hit me in the back of the head.
(01:53):
Oh, it's a note that says shop at merchanatomy.com.
So what causes Klinefelter Syndrome?
Klinefelter Syndrome is a genetic condition that is caused by an extra X chromosome.
This can either be from the sperm or from the egg.
In most cases, all cells will have two X chromosomes and one Y chromosome.
In the case of Mosaic Klinefelter Syndrome, some cells will have two X chromosomes and
(02:13):
one Y chromosome, whilst others will have the regular one X and one Y chromosome.
This is normally the less severe version of Klinefelter Syndrome.
And there's also a form of Klinefelter Syndrome that is less common, where there is more than
one extra copy of the X chromosome.
This leads to more severe symptoms.
How common is Klinefelter Syndrome?
Depending on the source, Klinefelter Syndrome occurs in between one in 3,000 males and every
(02:37):
one in 600 males.
However, it is estimated that up to 70 to 80% of them don't know they have the condition.
How do we test for Klinefelter Syndrome?
Testing for Klinefelter Syndrome will depend on when the development of symptoms has occurred.
If a doctor notices atypical development around puberty, they may recommend screening for
Klinefelter Syndrome.
A doctor may also recommend screening for Klinefelter Syndrome in adulthood if a man
(02:59):
has low testosterone levels or is having issues with infertility.
Klinefelter Syndrome can also be picked up during pregnancy.
This is normally picked up when testing is done for other reasons, such as family history
of genetic conditions or pregnancy over the age of 35.
This testing looks at the fetal cells found in the amniotic fluid and checks them for
any abnormalities.
This test is called an amniocentesis or an amnio.
(03:21):
Klinefelter Syndrome may be suspected after a non-invasive test called the parental screening
test.
This is where blood is taken from the mother and it looks at the cell-free DNA in the sample.
This test can give an indication of potential genetic abnormalities but it is not a diagnosis.
If there is an indication of Klinefelter Syndrome or a different condition, it will be suggested
that further testing like an amniocentesis is performed.
(03:44):
The way we test for Klinefelter Syndrome is through genetics testing.
This is normally a blood test and is often a form of genetic testing called karyotype
testing.
It tells us how many chromosomes are present and the types of chromosomes present.
We will get right into the symptoms and presentation right after this little break.
(04:13):
If you've been enjoying this episode don't forget to check us out on BuyMeACoffee.
What symptoms might your child have if they had Klinefelter Syndrome?
Klinefelter Syndrome affects several areas of development.
These include the stages of development.
So a child with Klinefelter Syndrome will have slower than average motor development
meaning they may take longer to sit up, to crawl and to walk.
They may also speak later than their peers of the same age.
(04:36):
They may also struggle with learning and language problems such as having issues with reading,
writing, spelling and maths.
Klinefelter Syndrome can also affect physical appearance.
Issues of it can be seen through various things such as being taller than average, having
longer legs and a shorter body, narrow shoulders, broad hips and extra belly fat in comparison
to other male children.
(04:56):
When these children do go through puberty they have less lean muscle mass, less facial
hair when compared with their male peers.
These children can also have gynaecomastia which again is extra breast tissue.
They may also have low energy levels.
Klinefelter Syndrome also affects sexual development.
So this causes small firm testicles and a small penis.
(05:16):
It can also cause a condition called undescended testicles.
This is where the testicles do not move down from the abdominal area during development.
So when they are in the uterus.
Puberty is also delayed with not all of the changes occurring.
They may also have a low sperm count or lack of sperm which is a souspermia again and a
low sex drive.
Other symptoms include flat feet, increased risk of blood clots, higher risk of fractures.
(05:41):
This is caused by the osteopenia and osteoporosis which is the weakened bones, coordination
issues, radio ulnar sinostosis.
So this is an abnormal connection between the two bones in your forearm which is the
radius and the ulna.
Klinefelter Syndrome can also cause neurological symptoms.
These include anxiety, depression, social, emotional and behavioural issues, learning
(06:01):
difficulties like having trouble with language and reading, speech delays.
It has also been associated with autism spectrum disorder and attention deficit hyperactivity
disorder also known as ADHD.
The symptoms of Klinefelter Syndrome will vary from person to person.
What are some complications that doctors should be aware of when it comes to Klinefelter Syndrome?
There are several complications doctors should be aware of when it comes to Klinefelter Syndrome.
(06:22):
These include fertility issues and decreased sexual function.
Klinefelter Syndrome can cause azeospermia also known as a lack of sperm and low testosterone
levels.
Osteoporosis.
This is thin and brittle bones.
Normally people associate this with women but it can be caused by Klinefelter Syndrome.
Cancer.
With Klinefelter Syndrome there is an increased risk of certain cancers including breast cancer.
(06:43):
If you want to learn more about breast cancer we discuss it in episode 13.
Heart and blood vessel disease.
Lung disease.
Autoimmune diseases such as rheumatoid arthritis and lupus.
We explain both of these in episode 43 and episode 35.
Metabolic Syndrome.
This also includes an increased risk for type 2 diabetes which we covered in episode 26.
High blood pressure, high cholesterol and high triglycerides.
(07:05):
How do we treat Klinefelter Syndrome?
Klinefelter Syndrome will depend on the symptoms and the age at diagnosis.
Testosterone therapy is one of the more common therapies used.
For those who are young this can stimulate puberty and the changes that occur at puberty
like the deeper voice, body and facial hair as well as an increase in muscle mass.
Testosterone therapy can also help to strengthen the bones.
(07:27):
There are several different methods that may be used when it comes to testosterone therapy.
The method your doctor may prescribe or recommend will depend on your specific case.
Some of the methods that may be used include testosterone injections, testosterone gels
and testosterone patches.
Breast tissue removal.
For those with Klinefelter Syndrome that have developed gynaecomastia, surgery to remove
the excess tissue may be recommended.
(07:48):
Various forms of therapies can be used to help with the symptoms of Klinefelter Syndrome.
Some of the therapies that may be used include speech language pathologists.
These therapists help with the speech development.
Physical therapists.
These therapists help to build the muscle mass.
Occupational therapists.
These types of therapists can help with coordination and improving motor skills.
Everyone's treatment plan will be different as it will be based on what a person needs.
(08:10):
Klinefelter Syndrome is not often discussed in the media as it is not a very well known
condition.
Because of this there are not really any media portrayals of the condition nor are there
really any famous people with the condition.
I have shared a link to the Living with XXY page community stories for those who would
like to read the experiences of people with Klinefelter Syndrome.
The Living with XXY organisation also has a YouTube channel which features the founders
(08:33):
experiences and others with the condition.
This YouTube page also features helpful information from their medical advisor who is a paediatric
endocrinologist.
The page focuses a lot on bringing awareness and community, removing the stigma of having
Klinefelter Syndrome.
The founder Ryan Briante says "The stigmas of the past will not take away the voices
of the future" which highlights their goals and the work they are doing for those in the
(08:56):
Klinefelter community.
I definitely recommend checking them out if you are wanting to learn more about Klinefelter
Syndrome and managing the condition.
If you would like to check out a foundation for those in the US there is the American
Association for X and Y chromosome variations.
Their goal is to help individuals with XX or Y chromosomes including those with Klinefelter
Syndrome.
They provide support to those experiencing these conditions, education and encourage
(09:19):
research into these chromosome differences.
For those in the UK there is Klinefelter Syndrome Association.
They offer support and information for those affected by Klinefelter Syndrome, raising
awareness of the condition and also promoting research into the management of Klinefelter
Syndrome.
If you want to check out the sources, social media links or any other links you can head
to anatomyofilliness.com.
If you enjoyed this episode and would like to hear more subscribe to be notified about
(09:40):
our latest episodes.
If you want to join our community you can join us on Discord or Instagram.
If you want to check out more great content be sure to check us out on YouTube.
Otherwise stick around for the next episode.
Did you know most of the genes inside of your body aren't human?
(10:07):
This is because there are roughly the same amount of bacterial cells as there are human
cells in the body.
Their genomes contain 150 times more genes than ours.
Recently, your son Jack turned 15.
(00:03):
Although he has always been tall for his age, you can't help but notice he looks much
younger than his peers.
His friends are starting to sport facial hair and develop more muscular builds, while Jack
remains significantly skinnier and devoid of any facial hair.
It's not just his appearance that raises concerns.
You've noticed that he seems less confident in social situations, often shying away from
(00:24):
activities that involve his peers, which raises concerns about his health and his well-being.
Worried about his growth and development?
You decide to take him to a doctor for a thorough check-up.
(00:49):
Hello and welcome to Anatomy Of Illness.
Today's episode is about Klinefelter Syndrome.
Before we get into the condition, we are going to start with the history.
So why do we know Klinefelter Syndrome exists?
If you have been with us for a while and think we are worth five stars, don't forget to leave
us a review and share with a friend.
We begin around 1,000 years ago, over in Portugal.
There was a skeleton found in Portugal, specifically the Tor Velha archaeological site.
(01:12):
When its DNA was assessed, it was found to have the genetics of Klinefelter Syndrome.
Now we are going to jump forward to 1942.
This is where we meet Harry Klinefelter.
Dr. Klinefelter would describe the cases of nine men with gynaecomastia, small testes,
and azoospermia.
Gynaecomastia is an increase in breast tissue in men.
Azoospermia is a lack of sperm.
(01:32):
Now we move to 1959, as this is where we would finally understand the cause of Klinefelter
Syndrome.
This is where a study would first demonstrate men with the condition would have an extra
X chromosome.
So rather than being XY, they would be XXY.
I know, a short history, however, this disease has not been very well researched.
Ow!
Something just hit me in the back of the head.
(01:53):
Oh, it's a note that says shop at merchanatomy.com.
So what causes Klinefelter Syndrome?
Klinefelter Syndrome is a genetic condition that is caused by an extra X chromosome.
This can either be from the sperm or from the egg.
In most cases, all cells will have two X chromosomes and one Y chromosome.
In the case of Mosaic Klinefelter Syndrome, some cells will have two X chromosomes and
(02:13):
one Y chromosome, whilst others will have the regular one X and one Y chromosome.
This is normally the less severe version of Klinefelter Syndrome.
And there's also a form of Klinefelter Syndrome that is less common, where there is more than
one extra copy of the X chromosome.
This leads to more severe symptoms.
How common is Klinefelter Syndrome?
Depending on the source, Klinefelter Syndrome occurs in between one in 3,000 males and every
(02:37):
one in 600 males.
However, it is estimated that up to 70 to 80% of them don't know they have the condition.
How do we test for Klinefelter Syndrome?
Testing for Klinefelter Syndrome will depend on when the development of symptoms has occurred.
If a doctor notices atypical development around puberty, they may recommend screening for
Klinefelter Syndrome.
A doctor may also recommend screening for Klinefelter Syndrome in adulthood if a man
(02:59):
has low testosterone levels or is having issues with infertility.
Klinefelter Syndrome can also be picked up during pregnancy.
This is normally picked up when testing is done for other reasons, such as family history
of genetic conditions or pregnancy over the age of 35.
This testing looks at the fetal cells found in the amniotic fluid and checks them for
any abnormalities.
This test is called an amniocentesis or an amnio.
(03:21):
Klinefelter Syndrome may be suspected after a non-invasive test called the parental screening
test.
This is where blood is taken from the mother and it looks at the cell-free DNA in the sample.
This test can give an indication of potential genetic abnormalities but it is not a diagnosis.
If there is an indication of Klinefelter Syndrome or a different condition, it will be suggested
that further testing like an amniocentesis is performed.
(03:44):
The way we test for Klinefelter Syndrome is through genetics testing.
This is normally a blood test and is often a form of genetic testing called karyotype
testing.
It tells us how many chromosomes are present and the types of chromosomes present.
We will get right into the symptoms and presentation right after this little break.
(04:13):
If you've been enjoying this episode don't forget to check us out on BuyMeACoffee.
What symptoms might your child have if they had Klinefelter Syndrome?
Klinefelter Syndrome affects several areas of development.
These include the stages of development.
So a child with Klinefelter Syndrome will have slower than average motor development
meaning they may take longer to sit up, to crawl and to walk.
They may also speak later than their peers of the same age.
(04:36):
They may also struggle with learning and language problems such as having issues with reading,
writing, spelling and maths.
Klinefelter Syndrome can also affect physical appearance.
Issues of it can be seen through various things such as being taller than average, having
longer legs and a shorter body, narrow shoulders, broad hips and extra belly fat in comparison
to other male children.
(04:56):
When these children do go through puberty they have less lean muscle mass, less facial
hair when compared with their male peers.
These children can also have gynaecomastia which again is extra breast tissue.
They may also have low energy levels.
Klinefelter Syndrome also affects sexual development.
So this causes small firm testicles and a small penis.
(05:16):
It can also cause a condition called undescended testicles.
This is where the testicles do not move down from the abdominal area during development.
So when they are in the uterus.
Puberty is also delayed with not all of the changes occurring.
They may also have a low sperm count or lack of sperm which is a souspermia again and a
low sex drive.
Other symptoms include flat feet, increased risk of blood clots, higher risk of fractures.
(05:41):
This is caused by the osteopenia and osteoporosis which is the weakened bones, coordination
issues, radio ulnar sinostosis.
So this is an abnormal connection between the two bones in your forearm which is the
radius and the ulna.
Klinefelter Syndrome can also cause neurological symptoms.
These include anxiety, depression, social, emotional and behavioural issues, learning
(06:01):
difficulties like having trouble with language and reading, speech delays.
It has also been associated with autism spectrum disorder and attention deficit hyperactivity
disorder also known as ADHD.
The symptoms of Klinefelter Syndrome will vary from person to person.
What are some complications that doctors should be aware of when it comes to Klinefelter Syndrome?
There are several complications doctors should be aware of when it comes to Klinefelter Syndrome.
(06:22):
These include fertility issues and decreased sexual function.
Klinefelter Syndrome can cause azeospermia also known as a lack of sperm and low testosterone
levels.
Osteoporosis.
This is thin and brittle bones.
Normally people associate this with women but it can be caused by Klinefelter Syndrome.
Cancer.
With Klinefelter Syndrome there is an increased risk of certain cancers including breast cancer.
(06:43):
If you want to learn more about breast cancer we discuss it in episode 13.
Heart and blood vessel disease.
Lung disease.
Autoimmune diseases such as rheumatoid arthritis and lupus.
We explain both of these in episode 43 and episode 35.
Metabolic Syndrome.
This also includes an increased risk for type 2 diabetes which we covered in episode 26.
High blood pressure, high cholesterol and high triglycerides.
(07:05):
How do we treat Klinefelter Syndrome?
Klinefelter Syndrome will depend on the symptoms and the age at diagnosis.
Testosterone therapy is one of the more common therapies used.
For those who are young this can stimulate puberty and the changes that occur at puberty
like the deeper voice, body and facial hair as well as an increase in muscle mass.
Testosterone therapy can also help to strengthen the bones.
(07:27):
There are several different methods that may be used when it comes to testosterone therapy.
The method your doctor may prescribe or recommend will depend on your specific case.
Some of the methods that may be used include testosterone injections, testosterone gels
and testosterone patches.
Breast tissue removal.
For those with Klinefelter Syndrome that have developed gynaecomastia, surgery to remove
the excess tissue may be recommended.
(07:48):
Various forms of therapies can be used to help with the symptoms of Klinefelter Syndrome.
Some of the therapies that may be used include speech language pathologists.
These therapists help with the speech development.
Physical therapists.
These therapists help to build the muscle mass.
Occupational therapists.
These types of therapists can help with coordination and improving motor skills.
Everyone's treatment plan will be different as it will be based on what a person needs.
(08:10):
Klinefelter Syndrome is not often discussed in the media as it is not a very well known
condition.
Because of this there are not really any media portrayals of the condition nor are there
really any famous people with the condition.
I have shared a link to the Living with XXY page community stories for those who would
like to read the experiences of people with Klinefelter Syndrome.
The Living with XXY organisation also has a YouTube channel which features the founders
(08:33):
experiences and others with the condition.
This YouTube page also features helpful information from their medical advisor who is a paediatric
endocrinologist.
The page focuses a lot on bringing awareness and community, removing the stigma of having
Klinefelter Syndrome.
The founder Ryan Briante says "The stigmas of the past will not take away the voices
of the future" which highlights their goals and the work they are doing for those in the
(08:56):
Klinefelter community.
I definitely recommend checking them out if you are wanting to learn more about Klinefelter
Syndrome and managing the condition.
If you would like to check out a foundation for those in the US there is the American
Association for X and Y chromosome variations.
Their goal is to help individuals with XX or Y chromosomes including those with Klinefelter
Syndrome.
They provide support to those experiencing these conditions, education and encourage
(09:19):
research into these chromosome differences.
For those in the UK there is Klinefelter Syndrome Association.
They offer support and information for those affected by Klinefelter Syndrome, raising
awareness of the condition and also promoting research into the management of Klinefelter
Syndrome.
If you want to check out the sources, social media links or any other links you can head
to anatomyofilliness.com.
If you enjoyed this episode and would like to hear more subscribe to be notified about
(09:40):
our latest episodes.
If you want to join our community you can join us on Discord or Instagram.
If you want to check out more great content be sure to check us out on YouTube.
Otherwise stick around for the next episode.
Did you know most of the genes inside of your body aren't human?
(10:07):
This is because there are roughly the same amount of bacterial cells as there are human
cells in the body.
Their genomes contain 150 times more genes than ours.
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