Disease

Brief Summary

Klinefelter syndrome is a genetic condition in which a male individual is born with an extra X chromosome. Instead of the typical XY chromosomes in males, they have XXY, so this condition is sometimes called XXY syndrome.

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Source

Image:

Person with Klinefelter Syndrome

Frequency

This condition is one of the most common sex chromosome disorder which affects approximately 1 in 650 newborn boys.

Inheritance

Klinefelter syndrome is not inherited. it is due to the addition of an extra X chromosome that occurs during the formation of reproductive cells. an error called nondisjunction prevents X chromosomes from being distributed normally among reproductive cells as they form. However, because of nondisjunction, an egg cell or a sperm cell can also end up with an extra copy of the X chromosome.

History of Disease

In 1942, Dr. Harry Klinefelter, an endocrinologist with his colleagues from the Massachusetts General Hospital in Boston, published a report that was based on nine men who were found to have enlarged breasts, little no facial hair, a low sperm count and was unable to produce sperm, small testes, and a high pitched voice. Dr. Harry Klinefelter believed that the characteristics were caused by an endocrine disorder.

Later on, by the late 1950s, the cause for Klinefelter syndrome was discovered. The men who displayed the characteristics specific to the syndrome were found to possess an extra X chromosome. The syndrome was then named after Dr. Harry Klinefelter. Hence the name Klinefelter’s syndrome.

Brief Summary

History of Disease

KLINEFELTER SYNDROME

Pathogenesis

Klinefelter syndrome (XXY) is not an inherited condition. It occurs due to a random error that causes a male offspring to have an extra sex chromosome. Instead of having the normal 46 chromosomes, babies with Klinefelter syndrome have 47 (2n+1). Klinefelter can be caused by the following conditions:

One extra copy of the X chromosome in each cell (XXY). This may be a result of nondisjunction of either the maternal or paternal sex chromosome during meiosis I or II.

Mosaic Klinefelter syndrome - an extra X chromosome in some of the cells, which has fewer symptoms than nondisjunction.

Multiple copies of the X chromosome is very rare and can have severe symptoms or form.

Source

Image:

Mutated chromosome by Klinefelter Syndrome

Symptoms

Signs and symptoms of Klinefelter syndrome also vary by age.

Babies

Signs and symptoms may include:

slender trunk

short extremities, particularly in the proximal (rhizomelic) parts

a wide frontal bossed head

midface hypoplasia

Boys and teenagers

Signs and symptoms may include:

trident hand configuration

hyperextensibility of most joints, particularly the knees, is normal, but the elbow has restricted extension and rotation

Social Concerns

Klinefelter syndrome may increase the risk of anxiety and depression, social, emotional and behavioral problems, such as low self-esteem, emotional immaturity and impulsiveness.

Social Concerns

Treatment

Unfortunately, there is no cure available for Klinefelter syndrome. However, some associated problems 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 coordination problems associated with dyspraxia
Physiotherapy to help build muscle and increase strength
Psychological support for any mental health issues
Fertility treatment - this includes intracytoplasmic sperm injection or
ICSI where the sperm is removed to fertilise an egg in a laboratory

Source

Image:

Speech and Language therapy for individuals with Klinefelter Syndrome

Clinical Trials

Title:

Body Composition in Infants with Klinefelter Syndrome and Effects of Testosterone Treatment

Intervention:

Testosterone treatment of Testosterone cypionate (200 mg/ml) intramuscular injection

Phase:

Phase 4

Procedure:

This is a pilot study of body composition and testicular function in infants with KS compared to published norms for males by age, followed by a randomized trial of a short course of testosterone therapy with evaluation of change in body composition and motor development. Total study duration for each individual subject is 10-12 weeks.

Goals:

The primary outcome measure will be body composition (percent fat mass) as determined by the PEA POD. Secondary outcome measures will be 1) pre-treatment serum and urine gonadotropins and serum testosterone levels, 2) assessment of tone and motor abilities by an occupational therapist blinded to treatment assignment, and 3) stretched penile length.

Further details at:

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02408445.

https://clinicaltrials.gov/ct2/show/NCT02408445?cond=klinefelter&draw=2&rank=3

Clinical Trials

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