The risk of Klinefelter syndrome isn't increased by anything a parent does or doesn't do. Eur J Clin Invest. Klinefelter syndrome is a genetic condition that results when a boy is born with an extra copy of the X chromosome. Indeed, testosterone treatment of hypogonadal patients with type 2 diabetes primarily improves insulin sensitivity in obese patients 45but not in lean patients Continue reading from December 1, Previous: St. The extra genetic information may either be carried in every cell in the body or it may only affect some cells known as mosaic Klinefelter syndrome.
Whether this translates into 8. Symptoms of Klinefelter syndrome Klinefelter syndrome does not usually cause any obvious symptoms early in childhood, and even the later symptoms may be difficult to spot.
Nearly normal life expectancy . A more recent voxel-based morphometric study demonstrated a decrease of the total brain volume in XXY, which concerned both the grey and white matter, however correlation with data from neuropsychological test scores did not reveal significant associations between these differences and cognitive impairment.
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It isn't an inherited condition. Decreased penile size children
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Often there is an azoospermia present, rarely an oligospermia. Nevertheless, KS remains the strongest independent risk factor for male breast cancer and this risk is particularly elevated among patients with mosaic karyotypes. Retrieved December 11, Mayo Clinic Marketplace Check out these best-sellers and special offers on books and newsletters from Mayo Clinic.
Dtsch Arztebl Int. Close mobile hypogonadism in klinefelter s syndrome xxy navigation Un Navigation. We recently described a strikingly high incidence of the insulin resistance and the metabolic syndrome in 70 patients KS patients compared with age-matched controls. We advise lifelong treatment in order to prevent osteoporosis, obesity, metabolic syndrome, and diabetes. Medical treatment is mainly testosterone replacement therapy to alleviate acute and long-term consequences of hypogonadism as well as treating or preventing the frequent comorbidity. Arch Dis Child.
Clinical Klinefelterr. Pediatric Endocrinology Reviews. Overview Klinefelter syndrome is a genetic condition that results when a boy is born with an extra copy of the X chromosome. The syndrome is also the main cause of male hypogonadism. If gynecomastia is present, the surgical removal of the breast may be considered for both the psychological reasons and to reduce the risk of breast cancer.
When Leydig cell failure occurs before puberty, testosterone levels are five different types of mass movement, the normal changes of puberty do not develop, and the obvious hypogomadism of eunuchoidism are present. Clinical review: Klinefelter syndrome--a clinical update. Signs and symptoms of Klinefelter syndrome vary widely among males with the disorder. Klinefelter syndrome stems from a random genetic event. Treatment of KS should be a multidisciplinary task including pediatricians, speech therapists, general practitioners, psychologists, infertility specialists, urologists, and endocrinologists.
Both a gene dosage effect due to the supernumerary X-chromosome and androgen deficiency or a combination of both have been proposed to cause the neuropsychological phenotype seen in KS. High normal testosterone levels in infants with non-mosaic Klinefelter's syndrome.
Journal List Asian J Androl v. J Clin Endocrinol Metab 88 : —
Int J Androl 33 : — About Klinefelter syndrome. Nat Genet 16 : 54 — Physical examination including BP, height, weight, waist, testes, gynecomastia, and varicose veins. Previous: St. Treatment options include oral, transdermal, im, and buccal routes of administration Table 2
At fertilisation . Bibcode : Natur. Advanced maternal age is the only evidence-based risk factor for Klinefelrer. Above average heightweaker musclespoor coordination, less body hair, breast growthless interest in sex, infertility. Often symptoms are milder in mosaic cases, with regular male secondary sex characteristics and testicular volume even falling within typical adult ranges.
Human disease. This inactivated X chromosome can be microscopically visualised in female cells as the Barr body sex chromatin and has been shown to be regulated by X inactive specific transcript XIST gene. A case of a rare variant of Klinefelter syndrome, 47,XY,i X q Hererra Lizarazo A, et al. Retrieved March 23, Two or more X chromosomes in males . Help Learn to edit Community portal Recent changes Upload file.
Often there is an azoospermia present, rarely an oligospermia. Of particular importance is the length of a stretch containing polyglutamine coding CAG n repeats. National Human Genome Research Institute.
Author information Article notes Copyright and License information Disclaimer. Klinefelter syndrome predisposes patients to various venous diseases. Many boys and men do not realise they have it. Genotype and phenotype in Klinefelter syndrome-impact of androgen receptor polymorphism and skewed X inactivation. Klinefelter syndrome affects about 1 in newborn boys.
Clinical, x, and epigenetic features of the 46,XX male syndrome, compared with 47,XXY Klinefelter patients. In addition, we know that androgens can prevent the differentiation of pluripotent cells into an adipogenic lineage 59whereas hypogonadism independently predicts development of abdominal adiposity in men with normal chromosomes Genomics Glossary Autosomes: Chromosomes that are not sex chromosomes. Birth of healthy neonates after intracytoplasmic injection of ejaculated or testicular spermatozoa from men with nonmosaic Klinefelter's syndrome: a report of 2 cases.
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Ann Rheum Dis. Unfortunately, prospective studies addressing these issues are not at hand in KS patients, but are deemed necessary to prove the postulated efficacy of testosterone therapy in preventing the occurrence of the metabolic syndrome and to guide clinicians in the clinical care of these patients. Increased mortality in klinefelter syndrome. The high or normal to high level of estrogen may protect against excessive bone loss in KS. J Int Neuropsychol Soc.
Boys and men with Klinefelter syndrome typically have small testes that produce a reduced amount of testosterone primary testicular insufficiency. Related Associated Procedures Genetic testing Psychotherapy. Weight gain may occur during testosterone replacement therapy, due to the accumulation of lean body mass and fluid. The risk of Klinefelter syndrome isn't increased by anything a parent does or doesn't do.
Interestingly, a recent study by Samango-Sprouse et al.
Comparisons between XXY, Turner syndrome and controls suggest that this effect depends on the presence of an additional sex chromosome in a linear dose-dependent fashion.
Androgen treatment zxy middle-aged, obese men: effects on metabolism, muscle and adipose tissues. In our current study of structural brain volumes 49 we found the same volumetric changes as a previous study on boys with KS, 43 indicating that the difference in brain volumes seen in KS develop during fetal development either due to a gene-dosage effect or due to prenatal androgen deficiency.
Klinefelter syndrome: expanding the phenotype and identifying new research directions. Reprints are not available from the authors.
Increasingly, awareness is growing concerning a poor socioeconomic profile and psychiatric morbidity.
Accordingly, the particular habitus with disproportionately long legs accompanied by abdominal obesity is observable since infancy, hypogonadism in klinefelter s syndrome xxy a genetic syndrme. Archived from the original on 2 July April Often there is an azoospermia present, rarely an oligospermia. Signs and symptoms of Klinefelter syndrome vary widely among males with the disorder. Because of primary hypogonadism, individuals often have a low serum testosterone level, but high serum follicle-stimulating hormone and luteinizing hormone levels.
Journal of the International Neuropsychological Society. The testicles of affected males are usually less than 2 cm in length and always shorter than 3. Bibcode : PLoSO. Selective inactivation of the shorter of the two alleles would be associated with a more severe phenotype and diminished response to TRT. Prenatal Diagnosis. The standard diagnostic method is the analysis of the chromosomes' karyotype on lymphocytes.
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Testosterone replacement therapy reduces the risk of certain health problems, especially when therapy xxy started at the beginning of puberty. Am J Med Genet : 11 — Rarely, however, KS boys have micropenis, which can be treated successfully with topical testosterone cream or single injections with im testosterone Older children and adults with the condition tend to be somewhat taller than their peers. Mortality in patients with Klinefelter syndrome in Britain: a cohort study.
The Journal of Clinical Endocrinology and Metabolism. Older children and adults with the condition tend to be somewhat taller than their peers. Age-related presence of spermatogonia in patients with Klinefelter syndrome: a systematic review and meta-analysis. Archived from the original on 30 July
Hypogonadism in klinefelter s syndrome xxy Baltimore. Arch Intern Med. Nearly all patients with KS and breast cancer have gynecomastia, which may be a predisposing factor. Serum inhibin B levels reflect Sertoli cell function in normal men and men with testicular dysfunction. The authors thank John M. Men with these karyotypes have similar but often more severe phenotypes compared with those with the XXY karyotype.
National Human Genome Research Institute. Nature : — An echocardiographic study in twenty-two patients.
There is a paucity of data regarding sex steroid secretion in XXY patients during childhood, however, one should anticipate similarities to normal boys as this is, in general, a period of minimal Leydig cell function.
Information from reference 2. Monitoring of treatment should be based mainly on clinical effects including libido, ejaculate volume, body hair growth, muscle mass and energy levelbut should also be aimed at possible adverse effects.
Overview Klinefelter syndrome is a genetic condition that results when a boy is born with an extra copy of the X chromosome. Neurodevelopmental outcome of prenatally diagnosed boys with 47,XXY Klinefelter syndrome and the potential influence of early hormonal therapy.
Cancer incidence and mortality in men with Klinefelter syndrome: a cohort study. They believed that the hypogonadism arose primarily hypogonadism klinefelter failure syndrome xxy the Sertoli cells of the testes, the site of spermatogenesis, whereas the appropriate distribution of pubic and axillary hair indicated relatively normal function of the Leydig cells, which produce testosterone. Current approaches to hypogonadism in primary care? Klinefelter syndrome: clinical and molecular aspects.
Apart from one study, 92 all studies have shown decreased BMD 93949596 including recent studies on large cohorts of KS patients using modern DEXA scanning technology to measure bone density. Long-term outcome in children of sex chromosome abnormalities.
Epub Feb 22 doi:
Osteoporos Int 12 : 55 — Psychiatric disorders ranging from anxiety and neuroses to psychosis and depression are common in KS.
Am J Med Genet 48 : —
However, by this time, a therapeutic window during adolescence for treatment of hypogonadism, cognitive impairments, and psychosocial factors has been hypogonadism in klinefelter s syndrome xxy. Many of the cognitive xyx and psychological traits are already present in childhood, 34 before hypergonadotropic hypogonadism develops. Genet Med. Brain morphology in Klinefelter syndrome: extra X chromosome and testosterone supplementation. As a result of the small testes and decreased hormone production, affected males are infertile but may benefit from assisted reproductive technologies. N Engl J Med. There are 2 types of chromosome, called the sex chromosomes, that determine the genetic sex of a baby.
Views Read Edit View history. In some cases, the features of the condition are so mild that the condition is not diagnosed until puberty or adulthood, and researchers klinerelter that up to 75 percent of affected men and boys are never diagnosed. Archived from the original on 2 April Pediatric Endocrinology Reviews. Moreover, resting ECG evaluation may reveal a QTc interval shorter than in euploid men and women, which may be associated with fatal arrhythmias. Fertility management of Klinefelter syndrome. Testosterone replacement therapy reduces the risk of certain health problems, especially when therapy is started at the beginning of puberty.
Skip to hypogonacism Close Menu. Compared with unaffected men, adults with Klinefelter syndrome also have an increased hypogonadism in klinefelter s syndrome xxy of developing involuntary trembling tremorsbreast cancer if gynecomastia developsthinning and weakening of the bones osteoporosisand autoimmune disorders such as systemic lupus erythematosus and rheumatoid arthritis. Like this: Like Loading Breast cancer is a late event in the evolution of the KS phenotype as it is usually diagnosed in the 7th decade of life range 58—82 and is associated with increased mortality compared to normal men.
Five different types an Appointment at Mayo Clinic. Epub Dec 15 doi: Executive function Despite their average cognitive mass movement, it has been demonstrated that occupational achievements of XXY individuals still fall behind compared to their peers, suggesting that normal cognition is not adequate to compete in a complex social and working environment. Infertilityautoimmune disordersbreast cancervenous thromboembolic diseaseosteoporosis. Human Reproduction. Several theories try to explain the impact of a supernumerary X chromosome on the phenotypic features of XXY.
Taurodontism, an uncommon condition of the teeth affecting 0. Scientific Reports. Klinefelter syndrome is a chromosomal condition in boys and men that can affect physical and intellectual development. Birth Defects Orig Artic Ser 22 : —
Retrieved 4 September These and subsequent studies included a broader spectrum of XXY cases and demonstrated that the majority of XXY individuals fall within the average range concerning their intellectual abilities, behaviour, attention, social skills and adaptive functioning. This fact implies that the presence of a supernumerary chromosome may affect the expression of several genes throughout the genome. Mayo Clinic. Ultimately, the tissues of females are mosaics of cells with a different X inactivation pattern.
Nonetheless, cognitive profiles of mosaic Slimming world ireland do not differ significantly from patients with classical XXY, while androgen levels at early developmental stages have been shown to play syns honey role in neurodevelopment and brain lateralization, making it difficult to distinguish hormonal from genomic contribution in the phenotype. Nearly normal life expectancy . Share on: Facebook Twitter. Jacobs described her discovery of this first reported human or mammalian chromosome aneuploidy in her William Allan Memorial Award address. Compared to individuals with a normal number of chromosomes, studies indicate that males affected by Klinefelter's syndrome display behavioral abnormalities. Journal of the International Neuropsychological Society.
Recent studies have suggested that the observed low testosterone levels of XXY are not the result of diminished production, but of five different types of mass movement release into the testicular bloodstream due to aberrations of the testicular vasculature. The syndrome is also the main cause of male hypogonadism. Annual Review of Genomics and Human Genetics. Archived from the original on 18 March Hererra Lizarazo A, et al.
Academic difficulties may also persist in adulthood, however, over time, an increase is observed in VIQ relative to PIQ. Boys and men with Klinefelter syndrome tend to have better receptive language skills the ability to understand speech than expressive language skills vocabulary and the production of speech and may have difficulty communicating and expressing themselves. Acta Paediatrica. Archived from the original on 30 July
Without treatment, klinefdlter shortage of testosterone can lead to delayed or incomplete puberty, breast enlargement gynecomastiadecreased muscle mass, decreased bone density, and a reduced amount of facial and body hair. Support Center Support Center. The cognitive impairment is mainly in the area of language processing. Clinical review: Klinefelter syndrome--a clinical update.
The hidden proportion of nondiagnosed patients should be kept in mind when studying the estimates given in this table. In standard venipuncture, however, the ratio of normal to hyperdiploid white blood cells is not reflective of all tissues, and the phenotypic hypogonadism in klinefelter s syndrome xxy cannot be anticipated. Ratcliffe S. Combined, both epidemiological and clinical studies show clear evidence of a dramatically increased risk of diabetes and metabolic syndrome in KS. As a result, some of the body's cells have the usual one X chromosome and one Y chromosome 46,XYand other cells have an extra copy of the X chromosome 47,XXY. Shaded bars represent the ranges for controls; dots, values seen in patients with KS. Klinefelter syndrome KS 47, XXY is the most abundant sex-chromosome disorder, and is a common cause of infertility and hypogonadism in men.
Monitoring of treatment should be based mainly on clinical effects including libido, ejaculate volume, body hair growth, muscle mass and energy levelbut should also be aimed at possible adverse effects. Thus, more studies are needed to investigate the effect of testosterone therapy on cognition and brain morphology. Parents told of the diagnosis of KS should be carefully counseled on the wide variety of clinical manifestations that may be present in their child. This therapy also has positive effects on mood and self-esteem and has been shown to protect against osteoporosis, although it will not reverse infertility.
Acta Paediatrica. Nevertheless, KS remains the strongest independent risk factor for male breast cancer and this risk is particularly elevated among patients with mosaic karyotypes. PMC Some degree of language learning or reading impairment may be present,  and neuropsychological testing often reveals deficits in executive functionsalthough these deficits can often be overcome through early intervention. Not to be confused with XYY syndrome. Show references AskMayoExpert.
Epidemiological studies on both morbidity 810 and mortality in patients with KS 9 have confirmed this increased risk of diabetes. Despite being the most common sex chromosomal disorder affecting 1 in men, 1 Klinefelter syndrome KS 47, XXY remains highly under-diagnosed because of substantial variation in the clinical presentation. Intellectual and Psychiatric Disorders. Cell-free DNA prenatal screen, blood. Electroencephalographic, endocrine, and psychiatric status. The spectrum of the behavioral phenotype in boys and adolescents 47,XXY Klinefelter syndrome.
American Journal of Veterinary Research. Moreover, KS has been associated with verbal processing and attention deficits as well as social skill impairments, leading KS individuals to academic and professional achievements inferior to those of their peers of comparable socio-economic status. Publication types Review.
Fertility management of Klinefelter syndrome.
On the other hand, puberty in XXY subjects seem to occur in a timely fashion and follows a more or less normal course, with testosterone levels sufficient for satisfactory development of the secondary sexual characteristics and able to trigger a growth spurt. Archived from the original on 2 July
Klinefelter syndrome is a common cause for mental retardation of unknown etiology among prepubertal males. Syndroms M. During the s and s, increased prevalence of KS and 47,XYY was found in prisons and institutions for mentally handicapped individuals, and a general increased rate of criminal behavior and an increased crime rate were reported among both cohorts, especially due to sexual crimes 23 In standard venipuncture, however, the ratio of normal to hyperdiploid white blood cells is not reflective of all tissues, and the phenotypic severity cannot be anticipated.
In the past, the observation of the Barr body was common practice, as well. Clinical application of noninvasive prenatal screening for sex chromosome aneuploidies in 50, pregnancies: Initial experience in a Chinese hospital. The relevant nondisjunction in meiosis I occurs when homologous chromosomes, in this case the X and Y or two X sex chromosomes, fail to separate, producing a sperm with an X and a Y chromosome or an egg with two X chromosomes. About Klinefelter syndrome. Pediatric Endocrinology Reviews.
Novel insights in the regulation and mechanism of androgen action on bone. Create a free personal account to make a comment, download free article PDFs, sign up for alerts and more. Related articles in Web of Science Google Scholar.
Other differences can include abnormal fusion of certain bones in the forearm radioulnar synostosiscurved pinky fingers fifth finger clinodactylyand flat feet pes planus. The primary features are infertility and small poorly functioning testicles. Non-invasive prenatal testing for aneuploidy and beyond: challenges of responsible innovation in prenatal screening. Retrieved 27 August Epub Feb 22 doi:
When Leydig cell failure occurs before puberty, testosterone levels are low, the normal changes of puberty do not develop, and the obvious features of eunuchoidism are present. Learn More. Osteoporosis adults One study reported smaller left temporal volumes in KS men not receiving testosterone therapy compared to controls, whereas KS males receiving testosterone treatment did not differ from controls. Int Agency Res Cancer. Search ADS. Osteoporos Int —, 51with permission.
This may occur by the time the patient begins middle school i. Association between individual and country-level socioeconomic factors and work participation in spondyloarthritis including psoriatic arthritis: Analysis of the ASAS-perSpA study. Klinefelter syndrome KS 47, XXY is the most abundant sex-chromosome disorder, and is a common cause of infertility and hypogonadism in men. Decreased bone mass 5164 — 66 and outright fractures and osteoporosis affecting morbidity but also mortality 17 — 19 have long been linked to KS. Sign in to save your search Sign in to your personal account.
J Learn Disabil 29 : — In some cases, the features of the condition are so mild that the condition is not diagnosed until puberty or adulthood, and researchers believe that up to 75 percent of affected men and boys are never diagnosed. Natural history of seminiferous tubule degeneration in Klinefelter syndrome.
Social behavior and autism traits in a sex chromosomal disorder: Klinefelter 47XXY syndrome. Klinefelter syndrome 47,XXY. Lower levels of testosterone, free testosterone, and SHBG are found in obese men compared with nonobese men 62but the mechanism for lower testosterone in obese men remains unclear. Hum Mol Genet 16 : —
Most commonly, affected individuals are taller than average are unable to father biological children infertile ; however the signs and symptoms of Klinefelter syndrome vary among boys and men with this condition. Interestingly, a recent study by Samango-Sprouse et al. Chromosome abnormalities. Bibcode : Natur. May Often there is an azoospermia present, rarely an oligospermia.
Insulin-like factor 3 serum levels in normal men and 85 men with testicular disorders: relationship to the luteinizing hormone-testosterone axis. The effects klunefelter long-term hypogonadism may be diffi cult to discern from the gene dose effect of the extra X-chromosome. Prenat Diagn. Child Dev 53 : — Speculatively, changes in thyroid functioning may exacerbate low BMD 67 Warbury E A fertile patient with Klinefelter's syndrome. J Biol Chem.
Gonadal dysfunction and beyond: Clinical challenges in children, adolescents, and adults with 47,XXY Klinefelter syndrome. XXY males are hypgoonadism likely than other men to have certain health problems, such as autoimmune disordersbreast cancervenous thromboembolic diseaseand osteoporosis. Abstract Klinefelter syndrome KS is the most frequent chromosome disorder in males newborn malesdefined by 47,XXY karyotype. Epub Jul 28 doi:
The metabolic syndrome is frequent in Klinefelter's syndrome and is associated with abdominal obesity and hypogonadism. Hyperdiploid: Having more than 46 chromosomes in one cell. Collectively, substantial evidence points toward a dramatically increased risk of diabetes and metabolic syndrome in KS. Recently, new clinically important information regarding Klinefelter syndrome KS has been published. A number of congenital malformations and conditions are often seen in KS Table 1. Testicular size can be measured with a Prader orchidometer or ultrasonography.
Deficits in inhibitory executive functions in Klinefelter 47, XXY syndrome. Osteoporos Int 12 : 55 — All school-age boys should have their testes palpated as part of a complete physical examination, and those with learning disabilities or trouble with their peers deserve special attention. BMJ Open 2 : e Raboch J A clinical study of chromatin-positive men. Diabetes Care. Lancet : —
Most men with Klinefelter syndrome produce little or no sperm, but assisted reproductive procedures may make it possible for some men with Klinefelter syndrome to father children. Syncrome Ferri's Clinical Advisor A small blood sample is sufficient as test material. Compared to individuals with a normal number of chromosomes, studies indicate that males affected by Klinefelter's syndrome display behavioral abnormalities. Archived from the original on 2 April Some degree of language learning or reading impairment may be present,  and neuropsychological testing often reveals deficits in executive functionsalthough these deficits can often be overcome through early intervention. Deng C, et al.
J Neurol Neurosurg Psychiatry. Testosterone treatment in pubertal KS boys has also been reported to increase energy and endurance and to improve mood, concentration, and relations to othersand it seems that there are increased psychosocial problems in periods without testosterone treatment in pubertal KS
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John's Wort. External link.
Endocrine aspects of Klinefelter syndrome.
These are phenotypically displayed as higher level of anxiety and depression,  mood-dysregulation, and severe impairment in impulse control.
Treating hypogonadism in younger males. Hypogonadism in klinefelter s syndrome xxy in schoolboys with positive sex chromatin the Klinefelter syndrome. J Hypogonsdism Endocrinol Metab. Many boys with Klinefelter syndrome show few or only mild signs. Signs and symptoms of Klinefelter syndrome vary widely among males with the disorder. The hidden proportion of nondiagnosed patients should be kept in mind when looking at data concerning KS because ascertainment bias is always present, apart from screening studies in the newborn.
Prevalence and risk factors of diabetes in patients with Klinefelter syndrome: a longitudinal observational study. A randomized pilot study of monthly cycled testosterone replacement or continuous testosterone replacement versus placebo in older men. Mayo Clinic Laboratories. Both a gene dosage effect due to the supernumerary X-chromosome and androgen deficiency or a combination of both have been proposed to cause the neuropsychological phenotype seen in KS. Publication types Review. Testicular size can be measured with a Prader orchidometer or ultrasonography.
Diagnosis, Epidemiology, and Genetics
Recent systematic reviews. Of particular importance is the length of a stretch containing polyglutamine coding CAG n repeats. About 10 percent of boys and men with Klinefelter syndrome have autism spectrum disorder. Klinefelter syndrome is a chromosomal condition in boys and men that can affect physical and intellectual development.
In: Ferri's Clinical Advisor Orphanet Journal of Rare Diseases. The increased prevalence in XXY of several conditions which are usually more common in women than in men gynoid proportions, breast cancer, and autoimmune diseases may be explained by such genetic peculiarities. European Journal of Medical Genetics.
This variability may be attributed to the magnitude of androgen deficiency or inherent differences in the sensitivity of AR and, particularly, the length of the CAG repeats polymorphism. The testicles of affected males are usually less than 2 cm in length and always shorter than 3. April Cell-free DNA prenatal screen, blood. Mayo Clinic; As a consequence, XXY individuals are prone to suffering from learning difficulties and their achievements regarding academic performance and professional status are reported to be inferior to those of their peers of comparable socio-economic status.
Testicular biopsy specimens of infants with this disorder reveal only a reduced number of klinetelter hypogonadism in klinefelter s syndrome xxy 19 ; after the onset of puberty, however, the pathologic changes characteristic of KS such as hyalinization and fibrosis of the seminiferous tubules appear, leading to small, shrunken testes and azoospermia. Osteoporosis adults Endocrinology : — By pooling the data from eight different studies, we estimated the prevalence to be perlive-born males, confirmed by the prevalence in prenatally diagnosed KS in Denmark 12 and a large screening study from Georgia where DNA from dried blood spots from 36, newborn boys showed a prevalence of per ,