A chromosome is a rod-like structure present in the nucleus of all body cells, with the exception of the red blood cells, and which stores genetic information. Normally humans have 23 pairs of chromosomes, the unfertilised ova and each sperm carrying a set of 23 chromosomes. A normal female has an XX pair and a normal male an XY pair. The extent of the affect will depend upon the proportion of XXY to XY throughout the body. There is an enormous variation in the expression of this condition.
Some men are entirely normal and the diagnosis is only made for an incidental reason.
It may be that just some of the features are present, such as tall stature or delayed puberty. The syndrome is characterised by small testes, sterility and scant body hair. In some cases intellectual difficulties, especially in verbal skills,may be experienced. Additionally psychological problems with self image may be experienced by adolescent boys and adult men. Other chromosome abnormalities involving more than two X chromosomes in males may lead to learning difficulties.