Understanding Klinefelter syndrome and male infertility
Klinefelter syndrome, also called Klinefelter's, KS, or XXY, is a genetic condition that affects about 1 in 600 men. In this blog post, we explain what Klinefelter syndrome is, what causes it, and how it affects fertility.
What is Klinefelter syndrome?
Klinefelter syndrome occurs when a male is born with an extra X chromosome. This may cause various conditions like varicose veins, type 2 diabetes, heart diseases, and reduced lung functions.
What causes Klinefelter syndrome?
Normally, people have 23 pairs of chromosomes, which makes it 46 in total. One pair of chromosomes influences the sex of the person. Women typically have two X chromosomes and men typically have an X and a Y chromosome. However, men with Klinefelter syndrome have an extra X chromosome, which is why the disease is also called XXY. With the extra chromosome that causes Klinefelter syndrome, these men’s total number of chromosomes is 47 instead of 46.
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Signs and symptoms of Klinefelter syndrome
Signs of Klinefelter syndrome are different depending on age. Here below, you can see the most common symptoms in each age group.
| Boys from 0-9 | Boys/men from 10-19 | Men from 20-99+ |
| Cryptorchidism | Small testicles | Low level of testosterone |
| Small penis | Enlarged breasts (Gynaecomastia) | Infertility |
| Weak musculature | Long legs and short upper body | Reduced libido |
| Speech and language problems | Reduced muscle mass | Erection problems |
| Learning and reading difficulties | Delayed puberty | Neurocognitive problems related to decision-making and learning difficulties |
| Lacking social competences | Reduced beard and secondary body hair | Obesity |
| Behavioural difficulties | Low level of energy |
Source: NHS
Klinefelter syndrome can be hard to diagnose, and studies show that most people never receive a diagnosis. If you or your child experience any of the symptoms above and suspect the reason is Klinefelter syndrome, we recommend consulting a doctor as soon as possible. Early diagnosis and proper management can significantly improve quality of life.
How does Klinefelter syndrome affect fertility?
For most men with Klinefelter syndrome, the additional X chromosome results in decreased sperm production, low testosterone levels, and hormonal imbalance making natural conception highly unlikely.
Other articles about male infertility
Getting pregnant with Klinefelter syndrome
Thanks to advancements in the world of fertility treatment, it is possible for men with Klinefelter syndrome to experience the joy of fatherhood. Here below are some of the relevant options for men with Klinefelter syndrome.
Testosterone therapy
Life-long treatment with testosterone can help men with Klinefelter syndrome, as it ensures more muscle mass, libido, bone mass and a reduced risk of being overweight.
Fertility treatment with TESE
It used to be widely assumed that men diagnosed with Klinefelter syndrome were infertile. However, recent studies have revealed that some men with this condition retain small pockets of normal sperm production within their testicles. Through testicular sperm extraction (TESE), a procedure often performed with a microscope (micro-TESE), it may be possible to identify and retrieve viable sperm for fertility treatment.
The most common types of fertility treatments used with TESE are IVF and ICSI.
Treatment with donor sperm
If treatment with TESE is not an option or no pregnancy occurs after a couple of tries, donor conception could be an option. Contact our dedicated Customer Care Team for answers to any questions that might arise.
Adoption
Adoption is also a possibility for men unable to conceive using their sperm.
A personal story of dealing with Klinefelter syndrome
Michael was diagnosed with Klinefelter syndrome in his late teens. During his life, he always felt different from others, as he was taller than his peers but struggled with muscle development and learning disabilities.
Follow the link to hear Michael share his story and how he learned to live with Klinefelter syndrome.
Frequently asked questions about Klinefelter syndrome
Do people with Klinefelter syndrome look younger?
Some men with Klinefelter syndrome can appear younger, as the disease has affected their testosterone level causing reduced beard and secondary body hair.
How does Klinefelter syndrome cause azoospermia?
Klinefelter syndrome affects the testicles, as the seminiferous tubules (the part of the testicle which produces the sperm) get damaged over time. This damage happens because the tissue becomes scarred and hardened.
At the same time, the cells that would normally grow into sperm are lost. Without these cells and with the tubules not working, most people with Klinefelter syndrome are unable to produce sperm.