Klinefelter Syndrome

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What is Klinefelter Syndrome? Klinefelter is a chromosomal disorder that occurs when a boy is born with an extra copy of the X chromosome. This genetic condition affects males and it often is not diagnosed until adulthood.  The condition was identified in 1942 by Henry Klinefelter. This etiology was considered to be due to an […] Read More

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Klinefelter Syndrome

What is Klinefelter Syndrome? Klinefelter is a chromosomal disorder that occurs when a boy is born with an extra copy of the X chromosome. This genetic condition affects males and it often is not diagnosed until adulthood.  The condition was identified in 1942 by Henry Klinefelter. This etiology was considered to be due to an unknown endocrine disorder, until 1959 when further research studies were done by Jacobs et al. Today, Klinefelter syndrome (KS) refers to a group of chromosomal disorders in which the normal male Karyotype, 46, XY, has at least one extra X chromosome.  Humans have 46 chromosomes, which include the 2 sex chromosomes, X and Y (fathers have XY, while mothers have XX). A female child will inherit X from the father and X from the mother, this having an XX genotype. A male child inherits Y from the father and X from the mother, thus having an XY genotype.  It is important to note that mothers only pass on X chromosomes to children. So it is the father’s contributed chromosome that determines the sex of the child (in all normal situations). Diagnosis
  • Physical Examination
Your doctor will ask you questions about symptoms and health, including examining the genitals and chest and assessing development and functioning.
  • Hormone Testing
Done using your blood and urine samples to reveal abnormal hormone levels.
  • Chromosome Analysis
A blood sample is analyzed in the lab to check the shape and number of chromosomes.
  • Amniocentesis
Invasive prenatal testing is done on a pregnant woman by removing amniotic fluid from the uterus for testing to confirm the KS status of the unborn baby. Treatment To receive treatment, you or your son may be diagnosed with Klinefelter syndrome with a term if health care professionals including:
  • Endocrinologist
  • Speech therapist
  • Pediatrician
  • Physical therapist
  • Reproductive medicine or infertility specialist
  • Genetic counselor,
  • Psychologist
There is no absolute remedy for KS or repair of the sex chromosome changes rather treatment is channeled to reduce its effects on the patient. The sooner the diagnose and subsequent treatment, the greater the benefits. However, it is never too late to get help. Some successful treatment for Klinefelter syndrome based on signs and symptoms may include:
  • Testosterone Replacement Therapy (TRT)
This is given (usually at the onset of puberty) to help stimulate changes that normally take place at puberty. These include developing a deeper voice, increased muscle, and growing facial and body hair. It also improves libido, bone density, and reduce osteoporosis, mood, and behavior. It does not prevent infertility.
  • Breast Tissue Removal
This process removes excess breast tissue from men who develop swollen breasts.
  • Fertility Treatment
This gives hope to men who are unable to father children because of the low or no sperm count. A procedure called intracytoplasmic sperm injection (ICS) may help remove from the testicle using a biopsy needle and injected directly into the egg.
  • Speech and Physical Therapy
Boys who have problems with speech, language, and muscle weakness benefit from these treatments. 
  • Educational Evaluation and Support
Boys with Klinefelter syndrome, who have difficulty in learning and socializing can benefit from these support services.
  • Psychological Counseling
A family therapist, counselor, or psychologist can be a great help to reduce emotional challenges among teenagers, young adults, and men when confronted with worries and mood changes. Complications Klinefelter syndrome may increase of risk of health conditions:
  • Social/emotional problems like low self-esteem, emotional immaturity, and impulsiveness.
  • Sexual misfits and infertility
  • Anxiety and depression
  • Osteoporosis
  • Heart and blood vessel disease
  • Lung disease
  • Breast cancers and some others
  • Type 2 diabetes
  • Hypertension
  • Hyperlipidemia (high cholesterol)
  • Rheumatoid arthritis.
  • Dental problems
  • Autism spectrum disorder (ASD)
Risk Factors Klinefelter syndrome is traceable to a random genetic error. The risk of the syndrome is not a result of the omission, actions, or inactions of parents. For older mothers, the risk is higher but only slightly. Life Expectancy People with Klinefelter syndrome have a normal life expectancy or very slightly reduced. However, patients who develop secondary diseases such as cancer may have a shorter life span. It was found that Klinefelter syndrome was associated with a significant increase in mortality risk of 40% corresponding to a significantly reduced median survival of 2 to 3 years.


The signs and symptoms of Klinefelter syndrome vary widely among males, and also by age. It had been observed that:

In babies, signs and symptoms may include:

  • Longer than average time to sit-up, crawl, walk, and even speak.
  • Weak muscles.
  • At birth, testicles that haven't descended into the scrotum.

Boys (include teenagers)

  • Penis is small
  • Small firm testicles
  • Weak bones (osteoporosis)
  • Swollen breast tissue
  • Taller than average stature
  • Longer legs, shorter torso, and broader hips than normal.
  • Absent, delayed, or incomplete puberty.
  • Less muscle, less facial, and body hair compared with other teens.
  • Always weak
  • Shyness or lack of self-esteem.
  • Difficulty in expressing thoughts and feelings or socializing.
  • Serious challenges in reading, writing, spelling, or mathematics.

Men (adults)

  • Absence of sperm or low sperm count.
  • Small testicles and penis
  • Low libido (low sex drive)
  • Weak bones (osteoporosis)
  • Reduced facial or body hair
  • Exceeds average height
  • Less muscular than another man
  • Swollen breast tissue
  • Extra fat and baglike belly
  • Decreased serum testosterone concentrations.
  • Increased serum follicle; stimulating hormone and luteinizing hormone concentrations.
  • Diabetes Mellitus.
  • Goiter (enlargement of the thyroid gland)
  • Various cancers may be prevalent.


Causes of Klinefelter Syndrome

The random genetic error that causes a male to be born with an extra sex chromosome is what results in the Klinefelter syndrome. Although KS is a genetic condition, it is not an inherited condition. 

KS can be caused by:

  • An extra copy of the X chromosome in each cell (XXY). This is the most common cause.
  • An extra X chromosome in some of the cells ()
  • More than one extra copy of the X chromosome. This is however rare and results in a severe form of KS.

These extra copies of genes on the X chromosomes have interference with male sexual development and fertility, as well as physical activities, language, and behavior.


Who is most likely to get Klinefelter syndrome?

Klinefelter syndrome occurs in about 1 out of 500 to 1000 baby boys. Women who get pregnant after age 35 are slightly more likely to bear a boy child with this syndrome than the younger ones.

At what age is Klinefelter syndrome diagnosed?

Chromosome analysis is the nest diagnosis procedure to confirm Klinefelter syndrome. The syndrome might be identified in pregnancy during a procedure to examine feral cells drawn from the amniotic fluid (amniocentesis) or placenta for another reason–such as being above 35 years old or having a family history of a genetic condition.

Does Klinefelter syndrome affect females?

Females can not have Klinefelter syndrome, only males are affected. Klinefelter syndrome is a result of a genetic abnormality in which makes have an extra copy of the X chromosome. Instead of the normal male Karotype, 46, XY, males with Klinefelter syndrome have 47, XXY pattern.

Does Klinefelter syndrome cause mental retardation?

Klinefelter syndrome has not typically been associated with mental retardation (MR), however, in recent years, a growing body of evidence suggested that Klinefelter boys often experience language deficits and academic challenges.

Is Klinefelter syndrome a disability?

Males with Klinefelter syndrome variants, who have a higher number of X chromosomes suffer from an intellectual disability. About 70% of patients have minor developmental and learning disabilities. KS patients are prone to osteoporosis and breaking bones; a situation which might lead to disability.