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[Klinefelter syndrome].

Klinefelter's syndrome is defined by males with at least one Y chromosome and at least two X chromosomes. It represents the most common major abnormality of sexual differentiation. The original description was characterized by eunuchoidism, gynecomastia, azoospermia, and small, firm testes. Patients tend to be taller than average, mainly because of the disproportionate length of their legs. Serum testosterone is low to normal and gonadotropins are elevated. Histologically, seminiferous tubules degenerate and are replaced with hyaline. Some complications are occasionally found such as neoplasm, osteoporosis, autoimmune diseases, and diabetes mellitus. Treatment options include testosterone replacement for correction of the androgen deficiency. Recently, intracytoplasmic sperm injection(ICSI) of testicular spermatozoa resulted in several deliveries.

Autoimmune Diseases↗

Clinical report: a case of Williams Syndrome and Klinefelter Syndrome.

INTRODUCTION: Williams syndrome (WS) is a rare but well recognised neurodevelopmental disease affecting the connective tissue and the central nervous system. Many patients are identified through the presence of dysmorphic features and associated cardiac abnormalities. Klinefelter syndrome (KS) is associated with gynaecomastia, small testes, azoospermia and elevated gonadotropin levels. They are recognised in the second decade of life by their tall stature and delay in pubertal development. A combination of constitutive WS and KS has yet to be described. CLINICAL PICTURE: We report a child with these genetic aberrations, highlighting the clinical characteristics of such an individual. CONCLUSION: The manifestations and interactions of both conditions are also discussed.

Body Height↗

Prenatal diagnosis of multiple pterygium syndrome associated with Klinefelter syndrome.

A nonlethal form of multiple pterygium syndrome (MPS) was diagnosed prenatally at 16 weeks of gestation with associated Klinefelter syndrome in the same fetus. The ultrasound findings were cystic hygroma, hypertelorism, micrognathia, low-set ears, flexion contractures of upper and lower extremities and rocker-bottom foot. Genetic amniocentesis revealed a 47,XXY karyotype. After genetic counseling, the parents decided to have a therapeutic abortion. We presented this case for the purpose of further describing the early ultrasound findings and clinical features of multiple pterygium syndromes. Also, what makes our patient unique is the coincidental presence of Klinefelter syndrome with MPS. To our knowledge, this is the first case in the literature in which a 47,XXY karyotype has been found in a fetus with multiple pterygium syndrome. The importance of delineating the exact subtype of MPS and making a precise differential diagnosis becomes critical during the process of evaluation of patients with MPS.

Abnormalities, Multiple↗

The pituitary in klinefelter syndrome.

BACKGROUND: Klinefelter syndrome is a genetically determined primary gonadal defect characterized by the XXY karyotype. The testes are small, blood testosterone levels are low, and blood gonadotropin levels are elevated. Pituitary changes in patients with Klinefelter syndrome have not been evaluated in detail. DESIGN: The first patient, a 76-yr-old man, was operated for a large sellar mass. The second and third patients, a 62- and a 52-yr-old man, respectively, died of cardiac failure. Both the latter pituitaries were normal-sized and removed at autopsy. The diagnosis of Klinefelter syndrome was confirmed by genetic testing in all three cases. The formalin-fixed and paraffin-embedded pituitaries of three patients were evaluated for adenohypophysial hormone immunoreactivity. For immunohistochemistry, the streptavidin- biotin-peroxidase (ABC) complex method was applied. RESULTS: In case 1, histology and immunohistochemistry revealed an oncocytic gonadotroph macroadenoma immunoreactive for FSH and alpha subunit. No pituitary gland was evident. The pituitary of case 2 featured hyperplasia of gonadotrophs, some with features of "gonadal deficiency cells," and a microadenoma immunoreactive for GH. The pituitary of case 3 similarly showed hyperplasia of gonadotrophs and the formation of gonadal deficiency cells. CONCLUSION: Protracted stimulation of gonadotrophs due to lack of androgen feedback might have been a factor in the formation of the gonadotroph adenoma in case 1 and in the development of gonadotroph hyperplasia in cases 2 and 3. The clinically silent GH microadenoma of case 2 was regarded as an incidental finding.

Adenoma↗

A case of Moebius syndrome in association with Klinefelter syndrome.

PURPOSE: To describe an infant affected by Klinefelter syndrome, who also demonstrated clinical signs of Moebius syndrome. METHODS: A clinical case report. RESULTS: A male infant was born full-term to a healthy couple after an unremarkable pregnancy. Several dysmorphic features and generalized hypotonia were noted at birth. Chromosome study revealed a 47, XXY chromosome pattern, which is consistent with Klinefelter syndrome. The patient also demonstrated clinical findings of Moebius syndrome: bilateral horizontal gaze palsy, bilateral cranial nerve seven palsy, pointed tongue, pectoral muscle hypoplasia, and clubfeet. CONCLUSION: We report the first clinical case of a patient with Klinefelter syndrome who was also affected by Moebius syndrome. Although clinically intriguing, coexistence of the two syndromes most likely represents a chance occurrence.

Humans↗

[Infertility in the Klinefelter syndrome].

The Klinefelter syndrome is characterized by one or more extra X-chromosomes, deficient androgens, increased gonadotropines, fibrosis and hyalinization of the seminiferous tubules, small testes, gynecomastia, disproportionately long legs, sparse facial hair, and diminished sexual activity. The incidence of Klinefelter syndrome in the general population is 0.1-0.2%, some 3% among infertile patients, and approximately 11% in patients with aspermia. In very rare cases, these patients may manifest focal residua of spermatogenesis. Employing the ICSI method (intracytoplasmic sperm injection into an oocyte), a patient may be helped to father a child. There is, however an increased risk of such a child being born with a chromosomal aberration.

Adolescent↗

Early androgen deficiency in infants and young boys with 47,XXY Klinefelter syndrome.

BACKGROUND/AIMS: Klinefelter syndrome (KS) is characterized by the karyotype 47,XXY. In this study, we evaluated the physical and testicular failure phenotypes of infants and young boys with KS. METHODS: The evaluation included auxologic measurements, biologic indices of testicular function, and clinical assessment of muscle tone in 22 infants and young boys with KS, ages 1-23 months. RESULTS: Mean length, weight, and head circumference in SDS were generally within the normal range at -0.3 +/- 1.0, -0.1 +/- 1.4, and 0.0 +/- 1.5, respectively. Mean penile length and testicular volume SDS were -0.9 +/- 0.8 and -1.1 +/- 0.8, indicating significantly reduced penile and testicular size. Mean testosterone levels for the boys < or =6 and >6-23 months were 128 +/- 131 (4.4 +/- 4.5 nmol/l) and 9.5 +/- 7.2 ng/dl (0.3 +/- 0.2 nmol/l), respectively. High-arched palate was observed in 6/17 boys and clinodactyly (5th finger) was observed in 15/16 boys. Hypotonia was evaluated clinically and was noted to be present in 12/17 boys. CONCLUSION: The physical phenotype in infants and young boys with KS (1-23 months old) includes normal auxologic measurements and early evidence of testicular failure. Muscle tone was decreased in most of the boys. Testicular volume and penile length were diminished, indicating early androgen deficiency. The neonatal surge in testosterone was attenuated in our KS population. Thus, infants and young boys with KS have evidence of early testicular failure. The etiology of this failure and the clinical role of early androgen replacement require further study.

Androgens↗

Androgen receptor CAGn repeat length influences phenotype of 47,XXY (Klinefelter) syndrome.

CONTEXT: Klinefelter syndrome (KS; 47,XXY karyotype and variants) is characterized by tall stature and testicular failure, with marked variation in severity of the phenotype. Previous studies have proposed that genetic factors including mosaicism, parental origin of the supernumerary X-chromosome, skewed X inactivation, and androgen receptor (AR) polyglutamine repeat length may contribute to phenotypic variability in KS. OBJECTIVE: The objective of this study was to investigate the roles of these genetic factors in the variability of the KS phenotype. DESIGN: This was a cross-sectional study. SETTING: The study was performed at a pediatric endocrinology referral clinic. PATIENTS: Thirty-five KS boys and men, aged 0.1-39 yr, were studied. INTERVENTIONS: There were no interventions. MAIN OUTCOME MEASURES: Auxological measurements, biological indices of testicular function, and clinical assessment of muscle tone were the main outcome measures. Genetic studies included karyotyping to detect mosaicism, genotyping of microsatellite markers to determine parental origin of the supernumerary X-chromosome, and genotyping and methylation studies to measure AR polyglutamine (AR CAGn) repeat length and X inactivation ratio. RESULTS: The only genetic factor that significantly influenced the KS phenotype was the AR CAGn repeat length, which was inversely correlated with penile length, a biological indicator of early androgen action. Mosaicism, imprinting, and skewed X inactivation did not account for the variability of the KS phenotype. CONCLUSIONS: Normal genetic variation in the AR coding sequence may be clinically significant in the setting of early testicular failure and subnormal circulating testosterone levels, as occur in KS.

Adolescent↗

Rare XXY/XX mosaicism in a phenotypic male with Klinefelter syndrome: case report.

Klinefelter syndrome represents the most commonly found human sex chromosomal abnormality. It is characterized by small, firm testes with hyalinization of the seminiferous tubules, elevated gonadotropins and azoospermia. Males with Klinefelter syndrome may have a 47,XXY or a mosaic 47,XXY/46,XY constitutional karyotype and varying degrees of spermatogenic failure. Mosaicism 47,XXY/46,XX with clinical features suggestive of Klinefelter syndrome, is very rare and so far only 10 cases have been described in literature [1,2,5,8,10,15,22,23,25,44]. We report here a case of a mosaic 47,XXY/46,XX infertile male in whom detailed cytogenetic, histological and molecular studies were performed. Cytogenetic analysis revealed 80% and 50% mosaicism for the 46,XX cell line in blood lymphocytes and in skin fibroblasts, respectively, and the presence of 47,XXY cells only, in cultured testicular tissue. Testicular histopathology revealed atrophy of the testes with no spermatogenesis and absence of germ cells. Molecular analysis showed paternal inheritance of the extra X chromosome.

Adult↗

Fire-settng behavior associated with Klinefelter syndrome.

This is a report on a male patient with a previous history of psychotic disorder who was arrested for arson. During the following hospitalization in a psychiatric unit, a genetic syndrome, namely Klinefelter syndrome (47,XXY), was diagnosed. The association between firesetting behavior and Klinefelter syndrome is reviewed, and the underlying explanatory hypothesis is discussed.

Adult↗

Leydig cell tumor of the testis in Klinefelter syndrome: MR detection.

Klinefelter syndrome is associated with the development of breast and extragonadal germ cell tumors in some patients. Leydig cell tumor in association with Klinefelter syndrome is a rare entity. We report such a case to illustrate the usefulness of MR imaging in detecting a testicular neoplasm when clinical examination and ultrasonography are equivocal.

Humans↗

Agnogenic myeloid metaplasia associated with Klinefelter syndrome: a case report.

Klinefelter syndrome is the most commonly diagnosed sex chromosome disorder among males. It is usually associated with 47 chromosomes, including two Xs and one Y. The formal cytogenetic designation for Klinefelter syndrome is 47, XXY; the extra sex chromosome is due to meiotic chromosomal nondisjunction. Increased risk of various malignant diseases has been recognized among patients with different congenital chromosomal abnormalities. Since the early 1960s, numerous reports have appeared of an increased risk of malignant neoplasms among patients with Klinefelter syndrome. Evidence suggests a correlation with increased incidences of germ cell tumors and breast cancers. Whether these patients are at an increased risk of hematologic malignant disease, especially acute leukemia, is still uncertain. This report describes a patient with agnogenic myeloid metaplasia and Klinefelter syndrome, an association not previously reported.

Cytogenetic Analysis↗