Klinefelter Syndrome	back to Medical Information
Written by Phil Heinricy · First published in 6ft+ magazine

Abnormalities of the sex chromosomes occur in about 1.5 per 1000 births, meaning that about 1200 children are born each year with one of these conditions.

Turners syndrome, in which all or part of the X chromosome is missing, affects only girls, and is easily recognised, with short stature being an obvious symptom.

Klinefelter syndrome was first described in 1942, its chromosomal basis was not confirmed until 1959. Caused by an extra X chromosome (47,XXY), in rare cases more than one extra chromosome may be present (48,XXXY; 49XXXXY), with each additional chromosome worsening the clinical conditions. Early reports gave weight to the features of eunuchoidism and sterility, male breast development, and mental retardation. It has since been shown that this is the worst case scenario, and that observed symptoms may cover a wide range of subtle differences. Known as the most common sex chromosome abnormality in males, it occurs in about 1.3 per 1000 male births. Females with the extra X chromosome occur about 1 per 1000 female births. First observed in females in 1959, they were referred to as "super females", although the term was ammended to triple X females, when it was noted that these cases were identified mainly in institutions for the mentally retarded.

At birth, infants are often smaller in respect of birthweight, length, and head circumference. During childhood, growth tends to be ahead of the child's peers, particularly in terms of leg length. Even by the age of three years leg length may be disproportionate to sitting height.

In a clinical study of XXY boys, two thirds of the boys developed steadily increasing obesity, while the rest displayed lean and lanky stature. In three boys, who had high growth velocities, malposition of the testes was observed, with ascent of one testis occuring, requiring orchidopexy. Testicular development was normal up to the age of one year, apart from a reduction in the number of spermatogonia. Later, tubular diameter became reduced, and germ cells were not seen. Testicular volume increased in all boys at puberty, but this was followed by involution in those with the greatest development, resulting in a slight reduction in final volume.

The onset of puberty was not delayed, and the magnitude of the pubertal growth spurt showed no significant differences in timing or magnitude. Therefore, because of the accelerated growth in early childhood, the final height attained was approximately four inches greater than might otherwise have been expected. IQ tests revealed that the range of those included in the study was 67-131, with a mean performance of 96.7. Delayed speech development in childhood was not uncommon, and speech therapy is beneficial. Learning difficulties at school were frequently observed, requiring careful assesment of progress. The passive behaviour of XXY and XXX children may often see them overlooked, or dismissed as dreamers, without full understanding of their difficulties. The range of IQ scores indicates that while learning difficulties may be experienced, superior cognitive ability is also possible, and too pessimistic a prognosis is to be avoided. When behavioural difficulties occur, psychiatric help, involving counselling and/or psychopharmalogical medication may be necessary.

The majority of children with sex chromosome abnormalities will be taller than expected, but their final height is likely to be at the upper end of the normal range, so intervention is rarely necessary. There is a possibility of reduced androgen production in the XXY boy during late puberty, which should be kept under review. If present, intramuscular or oral testosterone will curtail height, as well as improving masculinisation. If, for reasons of low intelligence, raised testosterone levels are undesirable, somatostatin may be of benefit in the future (Somatostatin is not currently licensed in this country, and is on trial in certain growth clinics only. Ed).

This information was condensed and adapted from an article by Dr Shirley Ratcliffe, in Growth Matters 6, published by Chapterhouse Codex.

Summary

Yes, I know that the previous bit was hard going but, if you are still with me, I should like to summarise the salient points.

Klinefelter syndrome is the result of a chromosomal abnormality, which is actually relatively common. Girls may suffer from the extra X chromosome, but they are referred to as triple X females, and will manifest slightly different symptoms, for obvious reasons. The term Klinefelter syndrome is only applied to the condition in the male. Generally speaking, the boy will be very tall as a child, but the growth velocity (the amount the child grows in a given period of time) will revert to normal at about the age of five. In effect, the child gets a head start in early life, and then simply maintains its lead over its peers.

Behavioural difficulties are sometimes observed, and psychiatric help may be necessary in extreme cases. Learning difficulties may go unnoticed for some time, as the frequently passive nature of boys with Klinefelter syndrome often causes them to be labelled as dreamers. It must be noted that not all Klinfelter sufferers will display intellectual impairment, and some will be of above average intelligence.Some children will tend toward obesity, while a lean and gangly stature is more commonly observed with Klinefelter syndrome. Some difficulties may develop with the testes, in that they either fail to descend, or ascend later in childhood. Minor surgery may be required to correct this. Puberty is neither advanced nor delayed in most cases, although some boys may be slow to develop secondary male characteristics, i.e beard growth, masculine voice, etc. It has been known for some boys to develop secondary female characteristics, i.e to develop breasts, although rarely to the point that plastic surgery is needed to correct it. The androgen deficiency, which causes this to happen, is easily corrected with testosterone.

It is fair to say that, in many cases, the effect of the syndrome is so mild that it goes unnoticed, until the male presents himself for fertility tests. One of the effects of Klinefelter syndrome is that it renders the male infertile, the sperm being either defective or not present. For this reason alone, it could be argued that it is essential that the syndrome is diagnosed. For many men, the pressures of society's implication that his being unable to father children makes him less of a man, may be extremely difficult to deal with; proper counselling, given in good time, will help to prepare him. Couples wishing to adopt children are subject to age restrictions, so it is advisable to begin the process early, in order to improve the chances of a successful adoption. Suddenly having to face the fact that he will never father a child of his own, when the upper age limit for adoption is either near or past, could place enormous strain on both the individual, and on his relationship.

Information on associated health difficulties does not appear to have been compiled.

The Klinefelter Organisation is a national self-help group for men aged 18+ with Klinefelter's syndrome (KS) mostly run by KS men. See website for contact information: www.klinefelter.org.uk. Most of their quarterly newsletters can be found on the website along with their flagship information sheet: "What is KS?".

The Klinefelter's Syndrome Association represents both adults (and their partners) and children (and their families) who have Klinefelter's Syndrome (KS) and its variants. See website for contact information: www.ksa-uk.co.uk.

XXY Talk.com has discussion and support forums for Klinefelter Syndrome.

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