The Scientific Background in Brief
In 1942 Dr Harry Klinefelter and his co-
By the late 1950's other researchers discovered that men with Klinefelter's Syndrome had an extra sex chromosome giving 47XXY instead of the more usual 46XY.
Based on studies in the US in the 1970's it is clear that KS is one of the commonest genetic abnormalities known; 1 in 500 to 1 in 1000 live births.
Women usually inherit two X chromosomes; one from each parent.
Men inherit an X from their mothers and a Y from their fathers.
However the meiosis that occurs in the cells destined to become eggs & sperm occasionally gives rise to an egg with two X's or a sperm with both an X and a Y.
There are two chances to produce an XXY male. Either an XY sperm fertilises an X egg or a Y sperm fertilises an XX egg.
There are other less common variations; for example 48XXXY or 49XXXXY. There is also a mosaic type where some body cells are 46XY
Boys with or without KS tend to look very similar, but when puberty occurs the testes remain small and this persists into adult life.
Infertility is usual & a lack of libido is likely. Some breast development is possible.
A KS male may develop a pear-
Men with KS tend to be tall but their limbs are disproportionately long compared with their bodies. Many also have big feet and obviously have problems getting clothing to fit.
Body hair may fail to appear and facial hair rarely attains the level that feelings of masculinity may desire.
Boys developing these characteristics are often teased at school and this may give rise to a boy "turning off" & exhibiting behavioural problems.
Many of these characteristics, but not the height or Infertility, may be relieved by Testosterone Replacement Therapy given from Puberty onwards. The level should be determined by the Endocrinologist.
Where insufficient Testosterone is present bone density may be reduced when the body
fails to lay down sufficient calcium & this may give rise to bone disease such as
Osteoporosis. For this reason all KS males should request Bone-