Klinefelter syndrome (sometimes called Klinefelter's, KS or XXY) is where boys and men are born with an extra X chromosome. Chromosomes are packages of genes found in every cell in the body.
Males with XXY syndrome are born with cells that have an extra X chromosome, or XXY. This can cause delayed development and puberty, a smaller penis and testicles, infertility, and other symptoms. The condition that causes XXY syndrome is present at birth and can't be changed.
A few 47,XXY cases with a female phenotype have been reported. These individuals have positive SRY (testis-determining factor). The genetic explanation of this phenomenon is unclear.
It is possible that an XXY male could get a woman pregnant naturally. Although sperm are found in more than 50% of men with KS3, low sperm production could make conception very difficult.
Double aneuploidy (Down-Klinefelter syndrome) is rare, with an estimated incidence of 0.4-0.9 cases per 10,000 male births and 11.7 cases per 10,000 cases of trisomy 21 [7]. It is characterized by the presence of a third copy of chromosome 21 plus an extra X chromosome, resulting in 48 chromosomes (48,XXY,+21).
There are 2 types of chromosome, called the sex chromosomes, that determine the genetic sex of a baby. These are named either X or Y. Usually, a female baby has 2 X chromosomes (XX) and a male has 1 X and 1 Y (XY). But in Klinefelter syndrome, a boy is born with an extra copy of the X chromosome (XXY).
Klinefelter syndrome can be caused by: One extra copy of the X chromosome in each cell (XXY), the most common cause. An extra X chromosome in some of the cells (mosaic Klinefelter syndrome), with fewer symptoms.
Research shows that between 95% and 99% of people with Klinefelter syndrome are infertile, because they do not produce enough sperm to fertilize an egg naturally.
Physical. As babies and children, XXY males may have weaker muscles and reduced strength. As they grow older, they tend to become taller than average. They may have less muscle control and coordination than other boys of their age.
Boys with Klinefelter syndrome might have some or all of these physical signs: a taller, less muscular body than other boys their age. broader hips and longer legs and arms. larger breasts (gynecomastia)
Overview. Turner syndrome, a condition that affects only females, results when one of the X chromosomes (sex chromosomes) is missing or partially missing. Turner syndrome can cause a variety of medical and developmental problems, including short height, failure of the ovaries to develop and heart defects.
During early development the gonads of the fetus remain undifferentiated; that is, all fetal genitalia are the same and are phenotypically female. After approximately 6 to 7 weeks of gestation, however, the expression of a gene on the Y chromosome induces changes that result in the development of the testes.
What Is the Life Expectancy for Klinefelter Syndrome? Life expectancy for patients with Klinefelter syndrome is reduced by five to six years. Patients diagnosed at a younger age seem to have a shorter lifespan, possibly because diagnosis at an earlier age is associated with a more severe phenotype.
The prevalence of 47,XXY, also known as Klinefelter syndrome, is estimated to be between 1 in 581 to 1 in 917 males, making it the most common sex chromosome aneuploidy (SCA) in humans [Coffee et al., 2009; Morris et al., 2008].
Research has shown that the average intelligence (sometimes known as IQ) of boys with Klinefelter Syndrome is lower than that of boys with the usual number of chromosomes. In one study, the average IQ score was 98 for boys with Klinefelter compared with a value of 112 in the other boys.
Klinefelter syndrome is a common genetic condition where a male is born with an extra X chromosome. Typically, a male has one X and one Y chromosome. People with Klinefelter syndrome can experience breast growth, breast cancer, osteoporosis, infertility and learning difficulties.
Klinefelter syndrome affects males only; females cannot have it. Klinefelter syndrome results from a genetic abnormality in which males have an extra copy of the X chromosome.
Adults with Klinefelter syndrome are usually taller than nonaffected adult males, reaching a mean final height of about 185 cm (73 in). XXY males (see the image below) also have disproportionately long arms and legs. About 25% of patients have fifth-finger clinodactyly.
People who are male have XY chromosomes. People who are females have XX chromosomes. People who are intersex may have a mix of chromosomes, such as XXY. Or they may have some cells that are XY and some cells that are XX.
Significantly, Sax did not consider either Klinefelter's or Turner syndrome as intersex, as they are not 'associated with ambiguous genitalia, or with any confusion regarding sexual identity' (177).
Frequency. Klinefelter syndrome (XXY aneuploidy) is the most common human sex chromosome disorder. Approximately 1 in 500-600 males is born with an extra X chromosome.
It's all about Dad's genes
That's with the assumption, though, that the man's sperm carries equal numbers of X and Y chromosomes. A man's X and a woman's X combine to become a girl, and a man's Y combines with a woman's X to become a boy.
The lungs are the last major organ to finish developing. When fully mature, they produce a chemical that affects the hormones in your body. Doctors are not sure why labor starts, but this chemical may be one of the causes.
Nature is designed to favour the conception of boys from September to November and girls from March to May because of an evolutionary mechanism aimed at keeping the overall sex ratio as near to 50:50 as possible, the scientists said.