Klinefelter Syndrome


What is Klinefelter Syndrome?

Klinefelter syndrome is a chromosomal disorder wherein there is an extra X chromosome in the cells of the affected males. Normally, males have the XY chromosome pattern. In patients with this kind of disorder, their chromosome pattern is XXY pattern [1].

Instead of having a normal number of chromosomes which is 46, the Klinefelter patients have a total of 47 chromosomes. It is also referred to as the XXY or 47,XXY syndrome [2].

The condition was named after Dr. Harry Klinefelter, an endocrinologist that belonged to the group that first described the symptoms of the disorder [1].


The Human Chromosomes

In humans, there is a total of 46 chromosomes. These chromosomes contain an individual’s DNA and genes. Out of these 46 chromosomes, 2 of them are sex chromosomes which identify the person’s gender.

In females, the components of their sex chromosomes are composed of two X chromosomes (XX). On the other hand, males possess the X and Y sex chromosomes (XY).

Aside from the determination of the gender based on the sex chromosomes, they also help in the identification of the individual’s sexual characteristics and fertility. [3]


Klinefelter Syndrome Causes

Unlike most of the genetic disorders, Klinefelter disease is not hereditary (meaning it is not passed down through families). It is actually caused by a random error in meiosis (cell division) when the formation of parent reproductive cells occurs. If the pregnancy is successful, the baby boy will be born with the Klinefelter Syndrome.

Due to the extra X chromosomes present in the male patients, disruption of their fertility and sexual development may result. In some male patients, they only have the X chromosomes in some of their cells. This condition is known as the mosaic Klinefelter syndrome. If an individual possesses more than one extra copy of the X chromosome, a more severe form of the disorder may be experienced. [4]


Klinefelter Syndrome Symptoms

There are varying symptoms and degrees of severity which may occur in males with Klinefelter syndrome. The manifestations exhibit depending on the number of XXY cells that the male has, the age his condition was diagnosed, and the amount of testosterone in the body. There may be some who will not manifest symptoms at all. On the other hand, there are also those who will manifest the symptoms [1].

The symptoms of the Klinefelter syndrome mainly affect these three areas:

Physical Symptoms

The appearance of physical symptoms of Klinefelter Syndrome depends on the level of testosterone in the body. In this condition, males have low levels of testosterone. The severity of the symptoms will be based on the deficiency of the mentioned hormone. The male body has a required amount of testosterone in every developmental stage or specific age. When it is insufficient, it greatly affects the growth and sexual development. [6]

During First year of life:

  • No obvious manifestation of the symptoms
  • In some male babies, they may have weaker muscles.
  • Their ability to crawl, walk, or sit up may be delayed.
  • Undescended testicles into the scrotum  [5,6]

For boys aged 5 years and above:

  • Taller than the non-klinefelter syndrome kids
  • Clumsier movements
  • Has more fats around the belly
  • Delays in the development of coordination, motor skills, muscle strength, and speed [6]

At puberty or adolescent stage:

  • Slower pubertal development
  • Less amount of facial and body hair
  • Smaller genital organs
  • Gynecomastia or breast growth
  • Reduced production of sperm
  • Less interest in sexuality
  • They have weaker bones which makes them more prone to bone fractures.
  • Reduced muscle tone
  • Abnormal body proportion characterized by wider hips and narrower shoulders
  • Lower energy [6]

Adult males with Klinefelter Syndrome manifest the following:

  • Smaller testes and possible shrinking of it
  • Deficient production of testosterone leading to lowered sexual interest and functioning as well as less growth of hair and muscles.
  • Gynecomastia (breast growth/development)
  • Decreased sex drive or interest
  • Infertility: Most patients with Klinefelter syndrome are infertile. The possibility of them being able to father a biologically-related child is through the aid of a specialist in fertility. [5, 6]

Also, males with Klinefelter syndrome are more prone to developing:

  • Osteoporosis
  • Breast cancer
  • Autoimmune diseases
  • Venous thromboembolic disease [2]

Behavioral and Social Symptoms

  • More quiet than others
  • Low level of confidence
  • Not really physically active
  • More restless or easy to feel anxious
  • On the other hand, they are very helpful and obedient. [6]

Learning and Language Symptoms

Most males diagnosed with Klinefelter syndrome have the ability to do well academically. They have normal intelligence quotient (IQ). For some cases, they are challenged in learning and speaking. Other language and learning-related symptoms of Klinefelter syndrome include:

  • Difficulty in expressing their needs and thoughts
  • Delay in learning how to talk
  • Difficulty in pronouncing words and distinguishing similar sounds
  • Longer processing of information
  • Poor comprehension of what they read [6]

Klinefelter Syndrome Pictures


Picture 1 : Klinefelter Syndrome signs

Image source : andrologyaustralia.org

Picture 2 : Klinefelter Syndrome signs

Image source : centracare.com

Picture 3 : Klinefelter Syndrome

Image source : aafp.org

Picture 4 : Klinefelter Syndrome chromosome

Image source : colorado.edu

Picture 5 : Klinefelter Syndrome and Turner syndrome (Difference in chromosomes)

Image source : tokyo-med.ac.jp

Klinefelter Syndrome Diagnosis

Though there is no cure yet for the sex chromosomal disorder caused by Klinefelter syndrome, early detection and prompt treatment is important to minimize its effects. [5]

1. Chorionic Villi Sampling

  • This procedure is done through amniocentesis wherein a sample of amniotic fluid will be obtained from the amniotic sac of a pregnant woman.
  • This test is used to detect for possible presence of chromosomal disorders or other medical problems in the baby. [6]

2. Chromosome analysis (Karyotype)

  • This is actually the confirmatory diagnostic test used to rule out the presence of Klinefelter syndrome.
  • This is performed by obtaining a small blood sample from the male infant. Then, the white blood cells are going to be separated from the obtained blood sample. After this, it will be mixed with a culture medium. Then, it will be incubated and later on evaluated for presence of chromosomal disorders such as Klinefelter syndrome. [3]

3. Hormone Testing

  • This is performed by getting urine or blood samples.
  • The results may reveal abnormal levels of hormones, such as low levels of testosterone in the body. [5]


Klinefelter Syndrome Treatment

Medical Treatments and Surgery

1. Testosterone replacement therapy

  • Since there are low levels of testoterone in Klinefelter syndrome, the number one treatment suggested is testosterone replacement therapy to prevent the severe lifelong effects of the disorder.
  • The therapy is initiated at the time of puberty to enable the body to change normally as it should.
  • This replacement therapy has numerous benefits to the male patients with Klinefelter Syndrome. These are: improvement of the muscle tone, development of the reproductive organs, producing more masculine appearance (facial and body hair growth), strengthening of bones, deepening of the voice, reduction of breast growth, fertility improvement as well as increasing focus and attention.
  • The testosterone replacement may be given through injections (given every 2 to 3 weeks), pills, patch, or gel applied on the skin. [5,6]

2. Fertility treatment

  • A common problem in Klinefelter Syndrome  is infertility since there is no sperm produced. In some cases, males with this condition only produce a minimal amount of sperm.
  • Intracytoplasmic sperm injection (ICSI): This procedure involves obtaining sperm from the testicle using biopsy needle and then it is injected directly to the egg cell.
  • Other options include artificial insemination and adoption. [5]

3. Breast Tissue Removal

  • One of the problems occurring in males with Klinefelter syndrome is gynecomastia or breast growth. In order to solve this, excess tissue in the breast may be removed that can be done by a plastic surgeon. As a result, this will leave a masculine-looking chest for the male. [5]


Therapeutic Options

1. Occupational therapists

  • Shyness and being quiet is one of the traits possessed by individuals with Klinefelter syndrome.
  • Occupational therapists assists these individuals by helping them develop their daily functioning skills which are needed for playing, socialization, and interaction with others.

2. Physical therapists

  • They can aid by designing exercises and activities which can help an individual with Klinefelter syndrome to improve motor skills and muscle strength, as well as balance and posture.

3. Behavioral therapists

  • They teach the shy and quiet kids on how to handle social interactions such as starting conversations. They also coach on how to cope with frustrations, anger, and emotions caused by their feeling of being “different”.

4. Psychologists

  • These specialists can assist the males with Klinefelter sybndrome to deal and cope effectively with their feelings such as depression, low self-esteem, self-doubt, and sadness.
  • Also, they can help families to accept the condition of their loved one who has the disorder and how they can offer support.

5. Family therapists

  • They are essential for providing counselling to a male affected with Klinefelter syndrome, the spouse, and other members of the family.
  • Family therapists can foster effective communication skills and coping strategies for the family. [6]

Educational Support

  • The kid’s teacher can help the child by breaking down huge tasKlinefelter syndrome into short and simple ones.
  • Also, assistance can be asked from the school counsellor and school nurse. [1, 5]


Klinefelter Syndrome Life Expectancy

Though children with Klinefelter syndrome may feel that they are “different” from others, there is a high chance that they can live a healthy and normal life. This is possible with the early diagnosis and treatment.  Most of them can experience behavioral and emotional problems, as well as school difficulties. But this doesn’t mean they will be stuck there. Most individuals diagnosed with Klinefelter syndrome can achieve full independence in their adulthood.

With regards to their life expectancy, there has been a research conducted in 1985 that suggests that individuals diagnosed with this sex chromosomal disorder have decreased life expectancy. According to the study, there is a chance of reduction of life expectancy by 5 years due to the probability of the occurrence of aortic valve diseases, tumors, and subarachnoid haemorrhages in these affected people. However, newer studies suggest that the individuals with Klinefelter syndrome have estimated reduced life expectancy of 2.1 years. These data are not yet definitive since there are still many questions about the data being presented. [2]



1. http://www.medicinenet.com/klinefelter_syndrome/article.htm

2. http://en.wikipedia.org/wiki/Klinefelter’s_syndrome

3. http://www.genome.gov/19519068

4. http://kidshealth.org/teen/diseases_conditions/genetic/klinefelter.html

5. http://www.mayoclinic.com/health/klinefelter-syndrome/DS01057/DSECTION=causes

6. http://www.nichd.nih.gov/health/topics/klinefelter/conditioninfo/Pages/symptoms.aspx


Please enter your comment!
Please enter your name here