Most of us have 46 chromosomes, or 23 pairs, which contain the genetic information that determines our physiology. Usually, the egg contains one X chromosome and the sperm contains either the X or the Y chromosome. Sometimes nature plays tricks on us and places an extra X chromosome in the egg or sperm.
Depending on what connection is made, either a boy or a girl is born. When an egg is fertilized by a sperm with an X chromosome, a baby girl is born. If fertilization took place with the participation of Y chromosomes – a boy will be born. These connections have definitions in biology. The female is referred to as XX and the male is XY.
However, it happens, although it is still unknown why, that an egg or a sperm cell has more, e.g. 24, chromosomes. If they stick together, the developing fetus will have 47 chromosomes. And this is the cause of the so-called chromosomal aberrations.
Extra X in boys
The boy’s extra X chromosome, whether taken from an egg or a sperm, contributes to the development of Klinefelter’s syndrome, a condition first described in 1942. The karyotype is the set of chromosomes in the somatic cell of the body. It is a characteristic of individuals of the same species, of the same sex or suffering from the same chromosomal aberration. The male karyotype with an extra X chromosome is referred to as 47 or XXY. The band performs in the frequency of 1: 500.
This form of male sex chromosome aberration is most common. It happens, however, that the body may contain an even greater number of X chromosomes. Then we are dealing with the 48 (XXXY) or 49 (XXXXY) karyotype. One in every 1000 boys born is born with such a burden (according to estimates). The disease occurs with equal intensity among all races and ethnic groups.
Consequences of the error
In boys with an extra X chromosome, testosterone production is disturbed and the testes are not developed properly. They are smaller than in healthy boys, but the size of the penis is normal. There is also less testosterone in the body. A characteristic feature of boys with an extra X chromosome is a very tall height, usually exceeding 185 cm, which in adolescence can cause disturbances in coordination of movements. These boys also have legs and arms longer than their peers. The body is weakly muscled and hairy. The chest and pelvis have a feminine shape. The most troublesome feature is gynecomastia, i.e. breast enlargement. It happens that in adulthood, men with gynecomastia decide to surgically remove the fatty tissue accumulated in the breast area. For the future of a boy, and later a man, with Klinefelter syndrome, azoospermia, i.e. the complete absence of sperm in semen, which results in infertility, is of great importance. But it does not affect sexual performance. The man can have normal intercourse. It is also important that the majority of men with an extra X chromosome do not have deviations from mental and emotional development. The exception to this rule is the burden of the organism with the next two chromosomes, ie karyotype 49. In this case, mental retardation often occurs.
Boys with the XXY karyotype tend to be shy and insecure. Due to the feminine appearance of their hips and breasts, they are exposed to unpleasant comments from their peers. Therefore, the child’s parents should be aware of this and support the child to prevent depression from developing.
Usually around the age of 12, boys are given hormonal drugs to help the body develop in the most masculine way possible. Treatment with testosterone promotes the development of muscle mass, which usually improves the appearance of the body and adds self-confidence.
Extra X in girls
The presence of extra X chromosomes in girls is called triple X syndrome, trisomy X or 47 XXX. This genetic defect is estimated to occur in one in every 1000 girls born to birth.
The mechanism of inheritance of an extra chromosome is not fully understood, as is the case with Klinefelter syndrome. Much is known about the consequences of such a genetic defect.
Effects of joining X
It is worth noting that many women with an extra X chromosome have little or no symptoms. A characteristic feature of girls is high growth, a small head, a wrinkle in the eye. It is a vertical fold of skin that covers the paranasal corner of the eye. The same fold occurs in people with Down syndrome, cat scream syndrome and fetal alcohol syndrome. In people with genetic conditions, the diagonal lines begin at the lower edge of the eyelid and extend over the upper eyelid. There is also weakened muscle tone, i.e. hypotension.
In girls, there is a delay in the development of speech and motor skills. These children later begin to sit down and walk. Sometimes dyslexia and emotional disorders result in difficulties in learning and establishing relationships with peers. Later in life, this translates into difficulties in building proper professional and family relationships.
Some women with an extra X chromosome experience premature ovarian failure. If this happens at a young age, stopping ovulation precludes motherhood. Usually, however, these women can have children.
The result of inheritance of an additional X chromosome may be epilepsy (occurs in about 10% of girls) and the presence of only one kidney. The latter defect, however, does not affect the functioning of the body.
Women who have an extra X chromosome are also often referred to as “super woman” or “meta-woman”.