Klinefelter Syndrome

Klinefelter syndrome is where males are born with an extra X chromosome. Chromosomes are packages of genes found in every cell in the body. There are 2 types of chromosomes, called the sec chromosomes, that determine the genetic sex of a baby. These are names either X or Y. 

Boys and men with Klinefelter syndrome are still genetically male, and often will not realize they have this extra chromosome, but occasionally it can cause problems that may require treatment. 

Karyotype of individual with Klinefelter syndrome

What are the symptoms of Klinefelter Syndrome? 

Klinefelter syndrome does not usually cause any obvious symptoms early in childhood, and even the later symptoms may be difficult to spot. 

Possible features, which are not always present, may include: 

• In babies and toddlers - weak muscles and very flexible (hyper mobile) joints, learning to sit up, crawl, walk and talk later than usual, being quieter and more passive than usual, having undescended testicle, only one testicle, or a smaller penis. 

• In childhood - shyness and low self-confidence, problems with reading, writing, spelling and paying attention, mild dyslexia or dyspraxia, low energy levels, and difficulty socialising or expressing feelings. 

• In teenagers - growing taller than expected for the family (with long arms and legs), broad hips, poor muscle tone and slower than usual muscle growth, reduced facial and body hair that starts growing later than usual, small, firm testes, and enlarged breasts. 

• In adulthood - inability to have children naturally, low sex drive, small, firm testiest, and erection problems. 

  
  

Health issues in Klinefelter syndrome

Many boys and men with Klinefelter syndrome will not be significantly affected and can live normal healthy lives. Infertility tends to be the main problem, although there are treatments that can help. However, men with Klinefelter syndrome are at a slightly increased risk of developing other health problems, including: 

• Type 2 diabetes

• Weak and fragile bones 

• Cardiovascular diseases and blood clots

• Autoimmune disorders, where the immune system mistakenly attacks the body), such as lupus

• An under active thyroid gland 

• Anxiety, learning difficulties and depression - although intelligence is usually unaffected 

• Male breast cancer - although this is very rare

Testing for Klinefelter syndrome 

Early diagnosis and treatment can help prevent health problems in the future. Treatment can help reduce some of the symptoms if necessary. In many cases, it is only detected if a man with the condition undergoes fertility tests. Your general practitioner may suspect Klinefelter syndrome after a physical examination and may suggest sending off a sample of blood to check reproductive hormone levels. The diagnosis can be confirmed by checking a sample for blood for the presence of the extra X chromosome. Klinefelter syndrome can also be picked up as part of some screening tests during pregnancy. 

Treatments for Klinefelter syndrome

There is no cure for Klinefelter syndrome, but some of the problems associated with the condition can be treated if necessary. 

Possible treatments include: 

• Testosterone replacement therapy

• Speech and language therapy during childhood to help with speech development 

• Educational and behavioural support at school to help with any learning difficulties or behaviour problems. 

• Occupational therapy to help with any co-ordination problems associated with dyspraxia

• Physiotherapy to help build muscle and increase strength

• Psychological support for any mental health issues 

• Fertility treatment - options include artificial insemination using donor sperm or possibly intracytoplasmic sperm injection, where sperm removed during a small operation are used to fertilise an egg in a laboratory

• Breast reduction surgery to remove excess breast tissue.

To find out more about testosterone replacement therapy, refer to this link: Testosterone therapy: Potential benefits and risks as you ageMayo Clinichttps://www.mayoclinic.org › in-depth › art-20045728

Reference List

MedlinePlus (2019). Klinefelter syndrome: MedlinePlus Genetics. [online] medlineplus.gov. Available at: https://medlineplus.gov/genetics/condition/klinefelter-syndrome/.

NHS Choices (2021). Klinefelter syndrome. [online] NHS. Available at: https://www.nhs.uk/conditions/klinefelters-syndrome/#:~:text=Klinefelter%20syndrome%20.