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In 1942, Dr. Harry Klinefelter and his coworkers at the Massachusetts General Hospital in Boston published a report about nine men who had enlarged breasts, sparse facial and body hair, small testes, and an inability to produce sperm. By the late 1950 s, researchers discovered that men with Klinefelter syndrome, as this group of symptoms came to be called, had an extra sex chromosome, XXY instead of the usual male arrangement, XY. In the early 1970 s, researchers around the world sought to identify males having the extra chromosome by screening large numbers of newborn babies. One of the largest of these studies, sponsored by the National Institute of Child Health and Human Development (NICHD), checked the chromosomes of more than 40, 000 infants. Based on these studies, the XXY chromosome arrangement appears to be one of the most common genetic abnormalities known, occurring as frequently as 1 in 500 to 1 in 1, 000 male births.
Although the syndrome's cause, an extra sex chromosome, is widespread, the syndrome itself-the set of symptoms and characteristics that may result from having the extra chromosome-is uncommon. Many men live out their lives without ever even suspecting that they have an additional chromosome. No one knows what puts a couple at risk for conceiving an XXY child. Advanced maternal age increases the risk for the XXY chromosome count, but only slightly. Furthermore, recent studies conducted by NICHD grantee Terry Hassold, a geneticist at Case Western Reserve University in Cleveland, OH, show that half the time, the extra chromosome comes from the father. Dr.
Hassold explained that cells destined to become sperm or eggs undergo a process known as meiosis. In this process, the 46 chromosomes in the cell separate, ultimately producing two new cells having 23 chromosomes each. Before meiosis is completed, however, chromosomes pair with their corresponding chromosomes and exchange bits of genetic material. In women, X-chromosomes pair; in men, the X and Y chromosome pair.
After the exchange, the chromosomes separate, and meiosis continues. In some cases, the Xs or the X chromosome and Y chromosome fail to pair and fail to exchange genetic material. Occasionally, this results in their moving independently to the same cell, producing either an egg with two Xs, or a sperm having both an X and a Y chromosome. When a sperm having both an X and an Y chromosome fertilizes an egg having a single X chromosome, or a normal Y- bearing sperm fertilizes an egg having two X-chromosomes, an XXY male is conceived.
According to Dr. Robinson, the director of the NICHD-funded study, XXY babies differ little from other children their age. They tend to start life as what many parents call "good" babies-quiet, undemanding, and perhaps even a little passive. As toddlers, they may be somewhat shy and reserved.
They usually learn to walk later than most other children, and may have similar delays in learning to speak. In some, the language delays Maybe be more severe; with the child not fully learning to talk until about age 5. Others may learn to speak at a normal rate, and not meet with any problems until they begin school, where they may experience reading difficulties. A few may not have any problems at all-in learning to speak or in learning to read. "It's one of the conflicts they have, " said Melissa, the mother of an XXY boy. "My son can understand the conversations of other 10 year olds. But his inability to use the language the way other 10 -year olds use it makes him stand out. " In addition to academic help, XXY boys, like other language disabled children may need help with social skills. Language is essential not only for learning the school curriculum, but also for building social relationships.
By talking and listening, children make friends-in the process, sharing information, attitudes, and beliefs. Through language, they also learn how to behave-not just in the schoolroom, but also on the playground. If their sons' language disability seems to prevent them from fitting in socially, the parents of XXY boys may want to ask school officials about a social skills training program. Ideally, XXY males should begin testosterone treatment as they enter puberty. XXY males diagnosed in adulthood are also likely to benefit from the hormone. A regular schedule of testosterone injections will increase strength and muscle sizes, and promotes the growth of facial and body hair.
In addition to these physical changes, testosterone injections often bring on psychological changes as well. As they begin to develop a more masculine appearance, the self-confidence of XXY males tends to increase. Many become more energetic and stop having sudden, angry changes in moods. What is not clear is whether these psychological changes are a direct result of testosterone treatment or are a side benefit of the increased self-confidence that the treatment may bring. As a group, XXY boys tend to suffer from depression, principally because of their scholastic difficulties and problems fitting in with other males their age. Sudden, angry changes in mood are typical of depressed people.
Other benefits of testosterone treatment may include decreased need for sleep, an enhanced ability to concentrate, and improved relations with others. But to obtain these benefits an XXY male must decide, on his own that he is ready to stick to a regular schedule of injections. Sometimes, younger adolescents, who may be somewhat immature, seem not quite ready to take the shots. It is an inconvenience, and many don't like needles.
Most physicians do not push the young-men to take the injections. Instead, they usually recommend informing XXY adolescents and their parents about the benefits of testosterone injections and letting them take as much time as they need to make their decision. Individuals may respond to testosterone treatment in different ways. Although the majority of XXY males ultimately will benefit from testosterone, a few will not.
To ensure that the injections will provide the maximum benefit, XXY males who are ready to begin testosterone injections should consult a qualified endocrinologist (a specialist in hormonal interactions) who has experience treating XXY males. Side effects of the injections are few. Some individuals may develop a minor allergic reaction at the injection site, resulting in an itchy welt resembling a mosquito bite. Applying a non-prescription hydrocortisone cream to the area will reduce swelling and itching.
In addition, testosterone injections may result in a condition known as benign prostatic hyperplasia (BPH). This condition is common in chromosomal ly normal males as well, affecting more than 50 percent of men in their sixties, and as many as 90 percent in their seventies and eighties. In XXY males receiving testosterone injections, this condition may begin sometime after age 40. The prostate is a small gland about the size of a walnut, which helps to manufacture semen. The gland is located just beneath the bladder and surrounds the urethra, the tube through which urine passes out of the body. In BPH, the prostate increases in size, sometimes squeezing the bladder and urethra and causing difficulty urinating, "dribbling" after urination, and the need to urinate frequently.
XXY males receiving testosterone injections should consult their physicians about a regular schedule of prostate examinations. BPH can often be detected early by a rectal exam. If the prostate greatly interferes with the flow of urine, excess prostate tissue can be trimmed away by a surgical instrument that is inserted in the penis, through the urethra. Turners Syndrome Turner Syndrome is a genetic disease in which all or part of the one X chromosome is missing, resulting in X females or partially XX females. It occurs in 1 of every 2, 000 - 2, 500 females born. The common anomalies of Turner syndrome include short stature, epicanthus folds, low nucl hair line, shield-like chest, webbed neck, high arched page coaptation of the aorta, ventricular septal defect, renal anomalies, pigmented nevi, lymphedema, hypoplasia nail and inverted nipples.
Its a disorder caused by the loss of genetic material from one of the sex chromosomes. Humans normally have a total of 46 chromosomes that are present in every cell if the body. DNA encodes genes, which specify all the proteins that make up the body and control INS functions. In humans, there are 23 matched pairs of chromosomes in every cell. Each cell contains 22 pairs of chromosomes called autosomes that are the same in males and females. The remaining pairing or chromosomes, the X and Y-chromosomes, are not shaped similarly, and thus are not matched in the same way as the autosomes.
During the process in which oocytes or sperm are formed, one of the sex chromosomes is sometimes lost. An embryo receiving only an Y-chromosomes can not survive, b and embryo receiving only an X-chromosomes may survive and develop as a female with Turner syndrome. While turner syndrome is genetic in that it involves the loss or abnormal expression of the X-chromosome gene, it is not usually hereditary in the conventional sense. That is, it does not typically run in families. The one exception to this observation are families with an X-chromosomes deletion which is stable enough to be passed down through the generations and which also allows fertility. Turner syndrome affects all races, nationalities and regions of the world equally, and parents who have produced many unaffected children may still have a child with turner syndrome.
There are no known toxins or environmental hazards that increase the chances of Turner syndrome. A woman with Turner syndrome has a low probability of being fertile, since the ovaries are negatively impacted in this disorder. However, if she does become pregnant and passes on her normal X-chromosomes to her offspring, no continuation of the syndrome is expected. Adults with turner syndrome are short, averaging around four feet, eight inches in height.
Girls with Turner syndrome dont start life as very short individuals; they become short over time, growing more slowly than their sisters and friends with each passing year. Studies have shown that medicine called recombinant human growth hormone, or GH, can improve the height of girls with Turner syndrome. However, these studies have tended to start GH treatment around age 9 or later, after years of deteriorating growth. So, even with treatment, many girls remain shorter than would be expected based on the heights of their parents. Turner syndrome is the complex phenotype of human females with complete or partial absences of the second sex chromosomes, or monopoly X.
A characteristic of neuro cognitive and psychosocial profile has also been described in TS females. Typically, specific deficits in visual-spatial / perceptual abilities, nonverbal memory function, motor function, executive function, and attention abilities occur in TS children and adults maturity and social skills. We hypothesize that a subset of the neuro cognitive deficits are genetically determined and result from abnormal expression of one or more X chromosome genes. In addition, a different subset if these neuro cognitive deficits result from a lack of estrogen and are at least somewhat reversible with estrogen treatment. The TS-associated psychosocial problems are most likely linked to these core neuro cognitive deficits and do no reflect a separate and independent component of the syndrome. Turner syndrome research has progressed significantly over the last decade.
The field has moved from descriptive reports based on single individuals or small clinical samples to the use of experimental designs with larger, more diverse and representative samples. This degree of variability among individuals with Turner syndrome in all domains suggest the need to identify risk and protective factors contributing to the heterogeneity in the phenotype. Active education about TS and participation in patient advocacy groups such as the Turner syndrome Society of the United States has provided new information for TS adults and Families as well as a supportive peer group.
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