Humans have 23 pairs of chromosomes carrying the genetic material that determines every aspect of our existence. In general, in some cases of chromosomal abnormalities, the abnormality may relate to the number of chromosomes: for example, a person could have one or more extra (supernumerary) chromosomes or could be missing a chromosome. On the other hand, the number of chromosomes could be normal, but the chromosomal disturbance could be a structural one (for example, a part of a chromosome may be missing or moved to another chromosome) (McGehee et al, 1976).
When it comes to the 23rd pair of human chromosomes that determines the sex of a person, similar chromosomal abnormalities can occur, which may lead to "primary amenorrhea- in women (that means girls never had a menstrual period) and infertility in men (McGehee et al, 1976).
In this essay I will explore the most common sex chromosome-related syndrome, Klinefelter syndrome which causes male infertilty. The history of the syndrome will be outlined first. The main body of the essay will present the pathophysiology and genetics of the syndrome, whom it affects, the frequency of the syndrome, the physical characteristics of the sufferers, in addition to lab findings, possible treatments, vulnerability to develop other diseases, how to detect the syndrome in a fetus and what is the prognosis. .
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HISTORY AND BACKGROUND.
The syndrome is named after Dr. Harry Klinefelter who published first a report on 9 men with enlarged breasts, little facial and body hair, small testes, and inability to produce sperm (Klinefelter et al, 1942). Other researchers in 1959 showed that such men have an extra sex chromosome (genotype or karyotype XXY) as compared to normal men (genotype XY) (cited in NICHD 2003). By the early 1970's, researchers around the world were searching for male babies with the extra sex chromosome by testing large numbers of newborns.
