Causes and Symptoms of Klinefelter Syndrome

In a human cell, there exists 44 autosomes and two sex chromosomes. The sex chromosomes in females are XX and in males are XY. It is the presence of the Y chromosome that leads to the development of a boy child. When males have an XXY pattern instead of the usual XY pattern, then the condition is termed as Klinefelter syndrome. It was Dr. Henry Klinefelter, an endocrinologist, who in 1942 was the first to describe this extra X chromosome condition, and thus this genetic disorder has been named after him.

What exactly is Klinefelter Syndrome?

Every male cell consists of 44 autosomes and XY sex chromosome. However, when the male body consists of 47 chromosomes instead of the usual 46, wherein the extra chromosome is an X sex chromosome, then it leads to a sex chromosome disorder called Klinefelter Syndrome. Not all males who have the extra X sex chromosome suffer from this syndrome. One in around 500 males have an extra X chromosome, but only one in every 1000 males suffers from this syndrome. This genetic disorder is seen to affect the sexual development of males and prevents the testes from functioning normally. Some males show the presence of this extra X chromosome in only few body cells. In such cases the symptoms of this disorder are milder.

Causes of Klinefelter Syndrome

This genetic order is not inherited and is a random event that occurs at the time of reproductive cell formation. The extra X chromosome is the result of nondisjunction of the sex chromosome during the sex cell division (meiosis). This sex cell division error contributes an extra sex chromosome to the baby's body. The exact reason why and how this error occurs is unknown. Increased maternal age can increase the risk of giving birth to a child with this syndrome. However, recent studies conducted by a geneticist at Case Western Reserve University in Cleveland revealed that in most cases the extra X chromosome comes from the father.

Cells which are to become the egg and the sperm undergo a reduction division called meiosis, wherein the 46 chromosomes in the cell are reduced to 23. Therefore, after meiosis the egg and sperm have only 23 chromosomes each. The egg and the sperm during meiosis exchange genetic matter with each other. (in women X and X pair and in men X and Y pair up). After the exchange of genetic material, the chromosomes separate and meiosis continues. Sometimes the XX or XY pairs fail to exchange genetic material. This leads to movement of the chromosomes to their cell itself, producing an egg or sperm respectively. When such a sperm already having an XY chromosome pair within itself fertilizes an egg with single X chromosome, it results in an XXY male.

Klinefelter Syndrome Symptoms

The severity of the symptoms depends on the number of cells with XXY pattern in the body and the level of male hormone, testosterone in the body. Physical, language and social development are three areas which are affected by this syndrome.

• Physical Growth and Development:
  Infants with this syndrome have weaker motor skills. Their muscles are weak and thus they take longer to sit up, crawl, walk and throw as compared to normal children. As they grow older, they grow taller, however, the hand-leg co-ordination abilities are weak with low muscle control. When these children reach puberty, their body produces lesser testosterone as compared to those males with the XY chromosome. Because of this, they grow taller, less muscular and have broad hips. Facial and body hair is also less. By the time they enter their teens, they have larger breasts, weak bones and less stamina as compared to normal males. In adulthood, Klinefelter syndrome men resemble normal men, however are taller and are more prone to health issues such as breast cancer, vein diseases, autoimmune diseases, osteoporosis and tooth decay. These men can lead normal sex lives, however, are infertile because their bodies produce little or no sperm.
• Linguistic Skills:Most of the males with this syndrome find it difficult to speak and read properly. They also find it cumbersome to express their views and thoughts, and also have difficulty in processing what they hear. It takes them more time and energy to carry out simply activities like reading and writing. However, many males suffering from this syndrome are gainfully employed and build successful careers.
• Social Skills:Klinefelter syndrome babies are quieter and less demanding than other babies. As they grow older, they develop into less confident, less active and shy individuals who find it difficult to cope or fit in with children their age. However, they are more obedient and helpful as compared to others. As adults, there is not much difference between Klinefelter syndrome men and normal men. They experience normal social lives with family and friends.

This chromosomal defect cannot be altered or treated and is a permanent condition. However, the severity of the symptoms can be reduced by testosterone treatment. This treatment ensures a more masculine appearance to the body. Planned and timely support provided for Klinefelter syndrome men while they are young will help reduce the psychological depression they tend to go through.