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1.
J Coll Physicians Surg Pak ; 24(10): 714-8, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25327912

RESUMEN

OBJECTIVE: To do clinical, hormonal and chromosomal analysis in undervirilized male / XY disorder of sex development and to make presumptive etiological diagnosis according to the new Disorder of Sex Development (DSD) classification system. STUDY DESIGN: Case series. PLACE AND DURATION OF STUDY: Endocrine Unit at National Institute of Child Health, Karachi, Pakistan, from January 2007 to December 2012. METHODOLOGY: Patients of suspected XY DSD / undervirilized male visiting endocrine clinic were enrolled in the study. Criteria suggested XY DSD include overt genital ambiguity, apparent female/male genitalia with inguinal/labial mass, apparent male genitalia with unilateral or bilateral non-palpable testes, micropenis and isolated hypospadias or with undescended testis. The older children who had delayed puberty were also evaluated with respect to DSD. As a part of evaluation of XY DSD, abdominopelvic ultrasound, karyotype, hormone measurement (testosterone, FSH, LH), FISH analysis with SRY probing, genitogram, laparoscopy, gonadal biopsy and HCG stimulation test were performed. Frequencies and percentages applied on categorical data whereas mean, median, standard deviation were calculated for continuous data. RESULTS: A total of 187 patients met the criteria of XY DSD. Age ranged from 1 month to 15 years, 55 (29.4%) presented in infancy, 104 (55.6%) between 1 and 10 years and 28 (15%) older than 10 years. Twenty five (13.4%) were raised as female and 162 as (86.6%) male. The main complaints were ambiguous genitalia, unilateral cryptorchidism, bilateral cryptorchidism, micropenis, delayed puberty, hypospadias, female like genitalia with gonads, inguinal mass. The karyotype was 46 XY in 183 (97.9%), 46 XX in 2 (1.1%), 47 XXY in 1 (0.5%), 45 X/46 XY in 1 (0.5%) patient. HCG stimulation test showed low testosterone response in 43 (23 %), high testosterone response in 62 (33.2%), partial testosterone response in 32 (17.1%) and normal testosterone response in 50 (26.7%). Genitogram was carried out in 86 (45.98%) patients. Presumptive etiological diagnosis of androgen sensitivity syndrome/ 5-alpha reductase deficiency, testicular biosynthetic defect/ leydig cell hypoplasia, partial gonadal dysgenesis, ovotesticular DSD, XX testicular DSD, mixed gonadal dysgenesis, testicular vanishing syndrome, klinefelter syndrome, hypogonadotropic hypogonadism, isolated hypospadias and isolated micropenis was made. CONCLUSION: Clinical, chromosomal and hormonal assessment may help in making the presumptive etiological diagnosis. Further molecular genetics analysis are needed in differentiating these abnormalities and to make a final diagnosis.


Asunto(s)
3-Oxo-5-alfa-Esteroide 4-Deshidrogenasa/deficiencia , Trastorno del Desarrollo Sexual 46,XY/etiología , Trastornos del Desarrollo Sexual/clasificación , Trastornos del Desarrollo Sexual/etiología , Hipospadias/etiología , Desarrollo Sexual/fisiología , Errores Congénitos del Metabolismo Esteroideo/etiología , Adolescente , Niño , Preescolar , Trastorno del Desarrollo Sexual 46,XY/diagnóstico , Trastornos del Desarrollo Sexual/diagnóstico , Trastornos del Desarrollo Sexual/genética , Femenino , Disgenesia Gonadal 46 XY/diagnóstico , Disgenesia Gonadal 46 XY/etiología , Humanos , Hipospadias/diagnóstico , Síndrome de Klinefelter/diagnóstico , Síndrome de Klinefelter/etiología , Masculino , Pakistán , Errores Congénitos del Metabolismo Esteroideo/diagnóstico , Testículo/anomalías , Testosterona
3.
J Clin Endocrinol Metab ; 98(1): 20-30, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23118429

RESUMEN

CONTEXT: Recently, new clinically important information regarding Klinefelter syndrome (KS) has been published. We review aspects of epidemiology, endocrinology, metabolism, body composition, and neuropsychology with reference to recent genetic discoveries. EVIDENCE ACQUISITION: PubMed was searched for "Klinefelter," "Klinefelter's," and "XXY" in titles and abstracts. Relevant papers were obtained and reviewed, as well as other articles selected by the authors. EVIDENCE SYNTHESIS: KS is the most common sex chromosome disorder in males, affecting one in 660 men. The genetic background is the extra X-chromosome, which may be inherited from either parent. Most genes from the extra X undergo inactivation, but some escape and serve as the putative genetic cause of the syndrome. KS is severely underdiagnosed or is diagnosed late in life, roughly 25% are diagnosed, and the mean age of diagnosis is in the mid-30s. KS is associated with an increased morbidity resulting in loss of approximately 2 yr in life span with an increased mortality from many different diseases. The key findings in KS are small testes, hypergonadotropic hypogonadism, and cognitive impairment. The hypogonadism may lead to changes in body composition and a risk of developing metabolic syndrome and type 2 diabetes. The cognitive impairment is mainly in the area of language processing. Boys with KS are often in need of speech therapy, and many suffer from learning disability and may benefit from special education. 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. CONCLUSIONS: More emphasis should be placed on increasing the rate of diagnosis and generating evidence for timing and dose of testosterone replacement. Treatment of KS should be a multidisciplinary task including pediatricians, speech therapists, general practitioners, psychologists, infertility specialists, urologists, and endocrinologists.


Asunto(s)
Síndrome de Klinefelter/etiología , Síndrome de Klinefelter/terapia , Composición Corporal/fisiología , Pruebas Genéticas , Glucosa/metabolismo , Homeostasis/fisiología , Humanos , Síndrome de Klinefelter/diagnóstico , Síndrome de Klinefelter/epidemiología , Masculino , Modelos Biológicos , Aptitud Física/fisiología , Hipófisis/fisiología , Testículo/fisiología
4.
J Clin Res Pediatr Endocrinol ; 4(4): 223-5, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-23032147

RESUMEN

49,XXXXY is a rare sex chromosome polysomy with an incidence of 1 in 85 000 male births. It has a characteristic triad of mental retardation, skeletal malformation and hypogonadism. This is the first case report of a child with 49,XXXXY syndrome and renal agenesis. This child was referred for genetic testing at 14 years of age due to facial dysmorphism and hypergonadotropic hypogonadism. He had coarse facial features, cryptorchidism of the right testis, genu valgus deformities, and patent ductus arteriosus which are known associations of 49,XXXXY syndrome. He also had agenesis of the right kidney, hydronephrosis of the left kidney with hydroureter which is not a known association of 49,XXXXY syndrome. The patient was the offspring of a mother with gestational diabetes. There is a strong correlation between maternal diabetes and congenital anomalies, especially renal and cardiovascular anomalies. Additionally, it has been noted that gestational diabetes increases the incidence of chromosomal aneuploidies. The teratogenic effects of maternal diabetes during embryogenesis may be the causative factor for the final phenotype of 49,XXXXY syndrome and renal agenesis.


Asunto(s)
Diabetes Gestacional/fisiopatología , Enfermedades Renales/congénito , Síndrome de Klinefelter/complicaciones , Anomalías Múltiples/etiología , Adolescente , Anomalías Congénitas/etiología , Anomalías Congénitas/fisiopatología , Anomalías Craneofaciales , Facies , Femenino , Humanos , Hipogonadismo/complicaciones , Hipogonadismo/etiología , Riñón/anomalías , Riñón/fisiopatología , Enfermedades Renales/complicaciones , Enfermedades Renales/etiología , Enfermedades Renales/fisiopatología , Síndrome de Klinefelter/etiología , Síndrome de Klinefelter/fisiopatología , Masculino , Atrofia Muscular/complicaciones , Atrofia Muscular/etiología , Embarazo
5.
Fertil Steril ; 98(2): 253-60, 2012 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-22749222

RESUMEN

Klinefelter syndrome is the most prevalent chromosome abnormality and genetic cause of azoospermia in males. The availability of assisted reproductive technology (ART) has allowed men with Klinefelter syndrome to father their own genetic offspring. When providing ART to men with Klinefelter syndrome, it is important to be able to counsel them properly on both the chance of finding sperm and the potential effects on their offspring. The aim of this review is twofold: [1] to describe the genetic etiology of Klinefelter syndrome and [2] to describe how spermatogenesis occurs in men with Klinefelter syndrome and the consequences this has for children born from men with Klinefelter syndrome.


Asunto(s)
Síndrome de Klinefelter/etiología , Síndrome de Klinefelter/genética , Espermatogénesis/genética , Animales , Azoospermia/etiología , Azoospermia/genética , Azoospermia/terapia , Humanos , Infertilidad Masculina/etiología , Infertilidad Masculina/genética , Infertilidad Masculina/terapia , Síndrome de Klinefelter/complicaciones , Masculino , Técnicas Reproductivas Asistidas/tendencias
6.
Med Princ Pract ; 20(5): 480-2, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21757941

RESUMEN

OBJECTIVES: To describe a case with the rare association of Klinefelter syndrome (47,XXY) and peripheral sensorimotor polyneuropathy. CLINICAL PRESENTATION AND INTERVENTION: A 50-year-old man with Klinefelter syndrome was referred to our neurology clinic complaining of pain, numbness and tingles in both legs, which began 10 years prior to admission. Two years before admission, the patient had difficulty in walking with progressive weakness. CONCLUSION: This report shows a patient with diagnosed Klinefelter syndrome, in whom symmetrical sensorimotor polyneuropathy developed in late adulthood.


Asunto(s)
Síndrome de Klinefelter/genética , Polineuropatías/genética , Electromiografía , Indicadores de Salud , Humanos , Síndrome de Klinefelter/diagnóstico , Síndrome de Klinefelter/etiología , Masculino , Persona de Mediana Edad , Debilidad Muscular , Polineuropatías/diagnóstico , Polineuropatías/etiología , Factores de Riesgo , Nervio Sural/patología
7.
SEMERGEN, Soc. Esp. Med. Rural Gen. (Ed. impr.) ; 37(1): 41-44, ene. 2011. tab, ilus
Artículo en Español | IBECS | ID: ibc-84925

RESUMEN

Se describe el diagnóstico de un paciente con síndrome de Klinefelter tras acudir a la consulta por un dolor testicular crónico. Representa un hallazgo casual, ya que el dolor testicular crónico no está descrito como síntoma clínico del síndrome de Klinefelter. Se revisa el síndrome de Klinefelter comparándolo con el caso en estudio. Y se revisa el proceso de diagnóstico del dolor testicular crónico, donde hasta el 25% de los casos queda sin resolver (AU)


A case of Klinefelter's syndrome is described. It was diagnosed in a patient who visited his doctor due to chronic testicular pain. Klinefelter's syndrome was a casual finding, as chronic testicular pain is not described as a clinical symptom of this disease. Klinefelter's syndrome is reviewed by comparing it with this clinical case. The diagnostic process of chronic testicular pain is also reviewed, as up to 25% of cases remain unresolved (AU)


Asunto(s)
Humanos , Masculino , Adulto , Síndrome de Klinefelter/complicaciones , Síndrome de Klinefelter/diagnóstico , Testículo/patología , Dolor/complicaciones , Dolor/etiología , Testosterona/uso terapéutico , Síndrome de Klinefelter/etiología , Síndrome de Klinefelter/fisiopatología , Síndrome de Klinefelter , Signos y Síntomas
8.
Rev. argent. endocrinol. metab ; 47(4): 29-39, oct.-dic. 2010. graf, tab
Artículo en Español | LILACS | ID: lil-641981

RESUMEN

El Síndrome de Klinefelter (SK) es la anormalidad cromosómica más frecuente en los varones, con una prevalencia estimada de 1:600 recién nacidos. El objetivo de este trabajo fue establecer las distintas características de presentación del SK a distintas edades, incluyendo signos y síntomas clínicos, parámetros de laboratorio y otros exámenes complementarios. La franja etaria más frecuente de diagnóstico de SK fue entre los 11 y 20 años (46,8%). En 4 casos el diagnóstico fue prenatal. Los motivos de consulta más frecuentes en forma global fueron la presencia de testículos pequeños, infertilidad y criptorquidia. El cariotipo más prevalente fue el clásico 47,XXY (83,7%), seguido del mosaico 47,XXY/46,XY (7,1%). El promedio de talla de nuestros pacientes prepuberales no mostró diferencia con la población general. Por otro lado, los pacientes puberales presentaron un promedio de talla significativamente más alto, hallándose alrededor de 1 SDS. Hubo correlación entre la edad y el SDS de talla. La media de talla de los adultos fue 178,8 ± 9,0 cm; se observó un 62,5% de sobrepeso/obesidad (IMC ≥ 25,0 kg/m²). El 50% de nuestros pacientes con SK menores de 18 años presentaron trastornos neurocognitivos. El hallazgo clínico más frecuente entre los pacientes prepuberales fue la criptorquidia. En los puberales las consultas y hallazgos clínicos más frecuentes fueron: testículos pequeños, criptorquidia y ginecomastia. Todos nuestros pacientes en estadio de Tanner igual o mayor de III presentaron testículos más pequeños para su grado de desarrollo. Los valores de FSH y LH fueron normales en los pacientes prepuberales y comenzaron a aumentar en la pubertad. Los adultos consultaron más frecuentemente por hipotrofia testicular, infertilidad y en menor grado ginecomastia. Todos los pacientes presentaron testículos hipotróficos, con una mediana de volumen testicular de 3,5 (1-8) ml. El 56,4% presentaron función sexual normal; el resto tuvo algún tipo de disfunción sexual. La testosterona total (TT) fue normal en 45% de los pacientes, con descenso consistente con la edad, donde todos los pacientes mayores de 40 años presentaron TT subnormal. El 10,7% de los pacientes que efectuaron espermograma tuvo oligospermia severa, el resto presentó azoospermia. La densitometría ósea fue anormal en el 46,4% de los adultos estudiados. Sin embargo, no hubo diferencias significativas en la prevalencia de osteopenia y osteoporosis entre los pacientes con TT normal o subnormal.


Klinefelter syndrome (KS) is the most common chromosomal aberration among men, with an estimated prevalence of 1:600 newborns. It is an X chromosome polysomy, with X disomy being the most common variant (47,XXY). The aim of this study was to establish the characteristics of KS presentation at different ages, including signs and symptoms, laboratory parameters and other diagnostic tests. The diagnosis of KS was more frequent in the age group between 11 and 20 years (46.8%). Most of the patients (83.7%) showed the classic 47,XXY karyotype and 7.1% showed a 47,XXY/46,XY mosaicism. While mean prepubertal height was not different from the control population, it was significantly higher at puberty. Patients consulted most frequently for small testes, infertility and cryptorchidism. In four cases the diagnosis was prenatal. 50% of our patients younger than 18 years presented neurocognitive disorders. The more frequent clinical findings were cryptorchidism in prepubertal patients; small testes, cryptorchidism and gynecomastia in pubertal patients. All our patients in Tanner stage III or more presented small testes. FSH and LH levels were normal in prepubertal patients and increased abnormally at puberty. On the other hand, most adults consulted for small testes, infertility and gynecomastia. 43.6% of patients had decreased libido, sexual and/or ejaculatory dysfunction. In adults average height (178.8 ± 9.0 cm) and weight (83.6 ± 21.0 kg), were higher than in the normal population, however 8 patients (19%) had a height less tan 170 cm. There was 62.5% of overweight / obesity (BMI ≥ 25.0 kg/m²) in the whole group of adult patients. 35.2% had eunuchoid proportions. All patients had testicular hypotrophc, with a median testicular volume of 3.5 ml (range 1-8 ml). Total testosterone (TT) levels were normal in 45% of adult patients, showing significant correlation with age. All patients aged 40 or more years had subnormal TT levels. In patients who underwent semen analysis, severe oligospermia and azoospermia were found in 10.7% and 89.3% respectively. Bone mineral densitometry showed low bone mass in 46.4% of cases. No significant differences in the prevalence of osteopenia and osteoporosis were observed among patients with normal or subnormal TT.


Asunto(s)
Humanos , Masculino , Recién Nacido , Lactante , Preescolar , Niño , Adolescente , Adulto , Persona de Mediana Edad , Síndrome de Klinefelter/etiología , Síndrome de Klinefelter/fisiopatología , Antropometría , Cariotipo , Síndrome de Klinefelter/diagnóstico
9.
Sex Dev ; 4(4-5): 249-58, 2010 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-20664188

RESUMEN

The prevalence of the Klinefelter's syndrome, ranging between 1/500 and 1/1,000 in the general male population, rises up to 3-4% among infertile males and to 10-12% in azoospermic patients. Due to the paucity of symptoms, only 10% of Klinefelter patients are diagnosed prepubertally. The clinical spectrum of the phenotype of adult Klinefelter patients is very broad and ranges from clinically overt hypogonadism to normally virilized males. The diagnosis is usually made during the evaluation of couple infertility. The only nearly constant clinical feature is the reduced testicular volume and azoospermia or, in few cases, cryptozoospermia. Due to the variability of the phenotype and also to the fact that the main symptoms of the syndrome (androgen deficiency, infertility) are in the reproductive domain, approximately two thirds of Klinefelter patients are not diagnosed during their life. Low/normal testosterone and high levels of the luteinizing hormone (LH) suggest that all Klinefelter patients have overt or compensated hypogonadism which should be treated with testosterone, starting from the peri-pubertal age. Even if no medical treatment is possible for infertility, testicular sperm for assisted reproduction techniques can be obtained by multiple testicular biopsies in experienced centers in up to 50% of subjects. Although there are no predictors for successful sperm retrieval, the birth of 101 children with normal karyotype was reported in the last 15 years. Furthermore, the genetic risk to the offspring of Klinefelter patients has recently not been found to be greater than that of patients with nonobstructive azoospermia with normal karyotype.


Asunto(s)
Síndrome de Klinefelter/patología , Síndrome de Klinefelter/terapia , Cognición/fisiología , Fertilidad/fisiología , Humanos , Síndrome de Klinefelter/etiología , Síndrome de Klinefelter/fisiopatología , Masculino , Fenotipo
10.
Arch Dis Child ; 95(11): 893-7, 2010 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-20584846

RESUMEN

OBJECTIVES: To determine whether older paternal age increases the risk of fathering a pregnancy with Patau (trisomy 13), Edwards (trisomy 18), Klinefelter (XXY) or XYY syndrome. DESIGN: Case-control: cases with each of these syndromes were matched to four controls with Down syndrome from within the same congenital anomaly register and with maternal age within 6 months. SETTING: Data from 22 EUROCAT congenital anomaly registers in 12 European countries. PARTICIPANTS: Diagnoses with observed or (for terminations) predicted year of birth from 1980 to 2005, comprising live births, fetal deaths with gestational age ≥ 20 weeks and terminations after prenatal diagnosis of the anomaly. Data include 374 cases of Patau syndrome, 929 of Edwards syndrome, 295 of Klinefelter syndrome, 28 of XYY syndrome and 5627 controls with Down syndrome. MAIN OUTCOME MEASURES: Odds ratio (OR) associated with a 10-year increase in paternal age for each anomaly was estimated using conditional logistic regression. Results were adjusted to take account of the estimated association of paternal age with Down syndrome (1.11; 95% CI 1.01 to 1.23). RESULTS: The OR for Patau syndrome was 1.10 (95% CI 0.83 to 1.45); for Edwards syndrome, 1.15 (0.96 to 1.38); for Klinefelter syndrome, 1.35 (1.02 to 1.79); and for XYY syndrome, 1.99 (0.75 to 5.26). CONCLUSIONS: There was a statistically significant increase in the odds of Klinefelter syndrome with increasing paternal age. The larger positive associations of Klinefelter and XYY syndromes with paternal age compared with Patau and Edwards syndromes are consistent with the greater percentage of these sex chromosome anomalies being of paternal origin.


Asunto(s)
Trastornos de los Cromosomas , Edad Paterna , Trisomía , Adulto , Trastornos de los Cromosomas/epidemiología , Trastornos de los Cromosomas/etiología , Cromosomas Humanos Par 13 , Cromosomas Humanos Par 18/genética , Síndrome de Down/epidemiología , Síndrome de Down/etiología , Métodos Epidemiológicos , Europa (Continente)/epidemiología , Humanos , Síndrome de Klinefelter/epidemiología , Síndrome de Klinefelter/etiología , Masculino , Edad Materna , Síndrome de la Trisomía 13
11.
Mol Hum Reprod ; 16(6): 386-95, 2010 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-20228051

RESUMEN

Klinefelter's syndrome (KS) is the most common chromosome aneuploidy in males, characterized by at least one supernumerary X chromosome. Although extensively studied, the pathophysiology, i.e. the link between the extra X and the phenotype, largely remains unexplained. The scope of this review is to summarize the progress made in recent years on the role of the supernumerary X chromosome with respect to its putative influence on the phenotype. In principal, the parental origin of the X chromosome, gene-dosage effects in conjunction with (possibly skewed) X chromosome inactivation, and--especially concerning spermatogenesis--meiotic failure may play pivotal roles. One of the X chromosomes is inactivated to achieve dosage-compensation in females and probably likewise in KS. Genes from the pseudoautosomal regions and an additional 15% of other genes, however, escape X inactivation and are candidates for putatively constituting the KS phenotype. Examples are the SHOX genes, identified as likely causing the tall stature regularly seen in KS. Lessons learned from comparisons with normal males and especially females as well as other sex chromosomal aneuploidies are presented. In addition, genetic topics concerning fertility and counseling are discussed.


Asunto(s)
Síndrome de Klinefelter/genética , Animales , Cromosomas Humanos X/genética , Femenino , Dosificación de Gen , Investigación Genética , Genotipo , Humanos , Síndrome de Klinefelter/etiología , Masculino , Modelos Biológicos , Fenotipo , Inactivación del Cromosoma X/fisiología
14.
Mol Cell Endocrinol ; 254-255: 154-62, 2006 Jul 25.
Artículo en Inglés | MEDLINE | ID: mdl-16765510

RESUMEN

Puberty is a time of striking changes in cognition and behavior. To indirectly assess the effects of puberty-related influences on the underlying neuroanatomy of these behavioral changes we will review and synthesize neuroimaging data from typically developing children and adolescents and from those with anomalous hormone or sex chromosome profiles. The trajectories (size by age) of brain morphometry differ between boys and girls, with girls generally reaching peak gray matter thickness 1-2 years earlier than boys. Both boys and girls with congenital adrenal hyperplasia (characterized by high levels of intrauterine testosterone), have smaller amygdala volume but the brain morphometry of girls with CAH did not otherwise significantly differ from controls. Subjects with XXY have gray matter reductions in the insula, temporal gyri, amygdala, hippocampus, and cingulate-areas consistent with the language-based learning difficulties common in this group.


Asunto(s)
Encéfalo/crecimiento & desarrollo , Pubertad/fisiología , Adolescente , Hiperplasia Suprarrenal Congénita/etiología , Adulto , Amígdala del Cerebelo/anatomía & histología , Encéfalo/anatomía & histología , Niño , Preescolar , Femenino , Hipocampo/anatomía & histología , Humanos , Síndrome de Klinefelter/etiología , Masculino , Tamaño de los Órganos/fisiología
15.
Hum Reprod Update ; 12(1): 39-48, 2006.
Artículo en Inglés | MEDLINE | ID: mdl-16172111

RESUMEN

Klinefelter syndrome (47,XXY) is characterized by small, firm testis, gynaecomastia, azoospermia and hypergonadotropic hypogonadism. Degeneration of the seminiferous tubules in 47,XXY males is a well-described phenomenon. It begins in the fetus, progresses through infancy and accelerates dramatically at the time of puberty with complete hyalinization of the seminiferous tubules, although a few tubules with spermatogenesis may be present in adult life. Activation of the pituitary-gonadal axis at 3 months of age is seen in Klinefelter boys similar to healthy boys. However, the level of testosterone in Klinefelter boys is significantly lower than in controls. After this 'minipuberty', the hormone levels decline to normal prepubertal levels until puberty. In puberty, an initial rise in testosterone, inhibin B, LH and FSH occurs in Klinefelter boys. However, the rise in testosterone levels off and ends at a low-normal level in young adults. Likewise, serum concentration of inhibin B exhibits a dramatic decline to a low, often undetectable level, concomitantly with a rise in FSH, reflecting the degeneration of the seminiferous tubules. Many hypotheses about the underlying mechanism of the depletion of the germ cells in Klinefelter males have been reported and include insufficient supranumerary X-chromosome inactivation, Leydig cell insufficiency and disturbed regulation of apoptosis of Sertoli and Leydig cells. However, at present, the exact mechanism remains unclear. In this article, we summarize current knowledge on the development of the classical endocrinological and histological features of 47,XXY males from fetus to adulthood and review the literature concerning the degeneration of the seminiferous tubules in this syndrome.


Asunto(s)
Síndrome de Klinefelter/etiología , Túbulos Seminíferos/patología , Factores de Edad , Animales , Apoptosis , Modelos Animales de Enfermedad , Dosificación de Gen , Humanos , Infertilidad Masculina/patología , Síndrome de Klinefelter/patología , Masculino , Pubertad , Testículo/embriología , Testículo/patología , Inactivación del Cromosoma X
18.
Am J Med Genet ; 98(1): 25-31, 2001 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-11426451

RESUMEN

Klinefelter (47,XXY) syndrome occurs in approximately 1:800 male births and accounts for about 10-20% of males attending infertility clinics. Recent studies have shown no obvious phenotypic differences between subjects in which the extra X-chromosome is of paternal or maternal origin; however, a minority of Klinefelter patients are adversely affected clinically and intellectually to an exceptional level, and the underlying basis of this phenotypic variation is not known. We hypothesize that skewed X-inactivation and possibly parental origin of the X-chromosomes is involved. In this study, we determined parental origin and inactivation status of the X-chromosomes in 17 cytogenetically confirmed 47,XXY cases, two 48,XXYY cases and one mosaic 46,XY/47,XXY case. Eight highly polymorphic markers specific to the X-chromosome and the polymorphic human androgen-receptor (HUMARA) methylation assay were used to determine the parental origin and X-inactivation status of the X-chromosomes, respectively. Overall, 17 cases were fully informative, enabling parental origin to be assigned. In 59% of cases, both X-chromosomes were of maternal origin (Xm); in the remaining 41%, one X was of maternal (Xm) and one was of paternal origin (Xp). In 5 of 16 (31%) cases informative at the HUMARA locus, skewed X-inactivation was observed as defined by greater than 80% preferential inactivation involving one of the two X-chromosomes. The two 48,XmXpYY cases both showed preferential paternal X-chromosome (Xp) inactivation. Three 47,XmXmY cases also showed preferential inactivation in one of the two maternal X-chromosomes. These results suggest that skewed X-inactivation in Klinefelter (47,XXY and 48,XXYY) patients may be common and could explain the wide range of mental deficiency and phenotypic abnormalities observed in this disorder. Further studies are warranted to examine the role of X-inactivation and genetic imprinting in Klinefelter patients.


Asunto(s)
Compensación de Dosificación (Genética) , Síndrome de Klinefelter/genética , Análisis Citogenético , Femenino , Marcadores Genéticos , Genotipo , Humanos , Síndrome de Klinefelter/etiología , Masculino , Padres , Fenotipo , Receptores Androgénicos/genética
19.
Med. UIS ; 11(3): 128-32, jul.-sept. 1997.
Artículo en Español | LILACS | ID: lil-232023

RESUMEN

El hipogonadismo masculino representa una diminución de la función testicular con una baja en la producción de testosterona e infertilidad. Puede ser ocasionado por un problema intrínseco de los testículos (hipogonadismo primario), una falla del eje hipotálamo-hipofisiario (hipogonadismo secundario) o una respuesta disminuída o ausente de los órganos blanco a los andrógenos (resistencia androgénica). Los síntomas del hipogonadismo incluyen la caída del vello corporal, disminución de la función sexual y cambios de la voz. Dependiendo de la edad de aparición puede presentarse atrofia testicular, hábito eunocoide y ginecomastia. A largo plazo puede presentarse osteoporosis. El diagnóstico se sospecha clínicamente y se establece con la demostración de concentraciones bajas de testosterona sanguínea. Si existe un aumento concomitante de las gonadotropinas circulantes, Hormona Folículo Estimulante y Hormona Luteinizante, se habla de un hipogonadismo primario; pero si ambas están disminuidas el hipogonadismo es secundario. Existen diferentes formas de testosterona para el tratamiento de los pacientes con hipogonadismo; la más común, es la testosterona de depósito (enantato o cipionato) la cual se inyecta por vía intramuscular. La terapia actual consiste en la administración de testosterona por vía transdérmica, no escrotal, obteniéndose una concentración normal de testosterona con preservación del ritmo cardíaco


Asunto(s)
Humanos , Masculino , Hipogonadismo/complicaciones , Hipogonadismo/diagnóstico , Hipogonadismo/tratamiento farmacológico , Hipogonadismo/epidemiología , Hipogonadismo/etiología , Hipogonadismo/patología , Hipogonadismo/fisiopatología , Hipogonadismo/rehabilitación , Hipogonadismo/terapia , Síndrome de Klinefelter/complicaciones , Síndrome de Klinefelter/diagnóstico , Síndrome de Klinefelter/epidemiología , Síndrome de Klinefelter/etiología , Síndrome de Klinefelter/fisiopatología , Síndrome de Klinefelter/genética , Síndrome de Klinefelter/rehabilitación
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