OBJECTIVE: To investigate the detection patterns, clinical phenotypic characteristics, and differences in diagnostic timeliness of Klinefelter syndrome (KS) across prenatal and postnatal stages, with an aim to provide a basis for optimizing strategies for early screening, diagnosis, and intervention. METHODS: A retrospective study was conducted to analyze data from two phases. The prenatal diagnosis group included 33,302 pregnant women who underwent amniocytic karyotyping due to advanced maternal age, abnormal ultrasound findings, or high-risk non-invasive prenatal testing (NIPT). The postnatal diagnosis group included 52,101 patients who underwent peripheral blood karyotyping due to primary infertility, abnormal external genitalia, or growth and developmental abnormalities. Additionally, medical histories of adult diagnosed patients were reviewed retrospectively to identify early occult symptoms. This study was approved by the Medical Ethics Committee of Chengdu Women's and Children's Central Hospital (Ethics No.: LCYJ-2025-030). RESULTS: In the prenatal group, 96 cases of KS were detected (detection rate 0.29%). The primary indications for referral were NIPT indicating sex chromosome abnormalities (45.83%), advanced maternal age (16.66%), and ultrasound abnormalities (17.70%). In the postnatal group, 128 cases of KS were detected (detection rate 0.25%). Clinical presentations were primarily primary infertility/azoospermia (77.34%), and the patients were predominantly adults (84.40%). Retrospective analysis revealed that adult patients presented with specific physical signs that had been overlooked during childhood. CONCLUSION As KS lacks typical early clinical manifestations, diagnosis is often delayed until adulthood when reproductive needs arise, showing a pattern of "passive detection" and resulting in missed opportunities for optimal intervention. By conducting a comparative analysis of prenatal diagnostic data and postnatal retrospective data, a risk association model linking prenatal screening indications with childhood-specific signs was developed. This study has provided empirical evidence for establishing a multidisciplinary, full life-cycle management system of "screening ~ diagnosis ~ monitoring ~ intervention" helping to shift from "passive detection in adulthood" to "proactive management across the entire life course," and laid a foundation for improving early diagnosis rate and long-term quality of life for patients.
Humans ; Klinefelter Syndrome/genetics* ; Female ; Adult ; Pregnancy ; Retrospective Studies ; Prenatal Diagnosis/methods* ; Male ; Phenotype ; Karyotyping ; Young Adult ; Adolescent ; Middle Aged

Humans ; Child ; Klinefelter Syndrome/complications* ; Lupus Erythematosus, Systemic/complications*

To investigate the factors affecting the sperm retrieval rate of microdissection testicular sperm extraction (micro-TESE) in patients with nonmosaic Klinefelter syndrome (KS), 64 patients with nonmosaic KS who underwent micro-TESE in the Center for Reproductive Medicine of Peking University Third Hospital (Beijing, China) between January 2016 and December 2017 were included in the study. Data on medical history, physical examination and laboratory examination results, and micro-TESE outcomes were collected. Patients were divided into two groups according to micro-TESE outcomes. The following factors were compared between the two groups by the Mann‒Whitney U test or Student's t-test based on the distribution (nonnormal or normal) of the factors: age, testicular size, follicle-stimulating hormone level, luteinizing hormone level, testosterone level, and anti-Müllerian hormone level. The overall success rate of sperm retrieval was 50.0%. Correlation analysis showed that testicular volume was positively correlated with testosterone level. Using a logistic regression model, age and anti-Müllerian hormone levels were found to be better predictors for the sperm retrieval rate than the other parameters.
Humans ; Male ; Sperm Retrieval ; Klinefelter Syndrome ; Microdissection ; Anti-Mullerian Hormone ; Semen ; Testis ; Spermatozoa ; Testosterone ; Azoospermia ; Retrospective Studies

Klinefelter syndrome (KS) is the most common genetic cause of human male infertility. However, the effect of the extra X chromosome on different testicular cell types remains poorly understood. Here, we profiled testicular single-cell transcriptomes from three KS patients and normal karyotype control individuals. Among the different somatic cells, Sertoli cells showed the greatest transcriptome changes in KS patients. Further analysis showed that X-inactive-specific transcript ( XIST ), a key factor that inactivates one X chromosome in female mammals, was widely expressed in each testicular somatic cell type but not in Sertoli cells. The loss of XIST in Sertoli cells leads to an increased level of X chromosome genes, and further disrupts their transcription pattern and cellular function. This phenomenon was not detected in other somatic cells such as Leydig cells and vascular endothelial cells. These results proposed a new mechanism to explain why testicular atrophy in KS patients is heterogeneous with loss of seminiferous tubules but interstitial hyperplasia. Our study provides a theoretical basis for subsequent research and related treatment of KS by identifying Sertoli cell-specific X chromosome inactivation failure.
Animals ; Humans ; Male ; Female ; Sertoli Cells/metabolism* ; Klinefelter Syndrome/genetics* ; Endothelial Cells ; Testis/metabolism* ; X Chromosome/metabolism* ; Mammals/genetics*

Objective: To investigate the clinicopathological characteristics of testicular biopsies from Klinefelter syndrome (KS) patients. Methods: The testicular biopsy specimens of 87 patients with KS (a total of 107 biopsy specimens) were collected from the Department of Pathology, Peking University Third Hospital, Beijing, China from January 2017 to July 2022. All patients were diagnosed as KS by peripheral blood karyotyping analysis. The testicular histopathologic features, testicular volume and hormone levels were evaluated retrospectively. The histopathologic analysis was used to assess the quantity and morphology of Leydig cells, the spermatogenic state of seminiferous tubules, the thickening of the basement membrane of seminiferous tubules and the changes of stroma. Results: Leydig cell proliferative nodules were seen in 95.3% (102/107) of KS testicular biopsy tissues. The eosinophilic inclusion bodies and lipofuscin in Leydig cells were found in 52.3% (56/107) and 57.9% (62/107) of specimens, respectively. The Sertoli cell only seminiferous tubules and the hyalinized tubules were found in 66.4% (71/107) and 76.6% (82/107) of the examined tissues, respectively. The tubules with complete spermatogenic arrest were found in 15.9% (17/107) of specimens, and 5.6% (6/107) of the specimens showed low spermatogenesis or incomplete spermatogenic arrest. In 85.0% (91/107) of the specimens, increased thick-walled small vessels with hyaline degeneration were identified. Conclusions: The most common features of KS testicular specimens are Leydig cell proliferative nodules, hyaline degeneration of seminiferous tubules and proliferation of thick-walled blood vessels. Testicular biopsy specimens of KS are rare. The pathologists can make a tentative diagnosis of KS based on the histological findings, combined with the ultrasound and laboratory results, which is helpful for further diagnosis and treatment of KS.
Male ; Humans ; Testis/pathology* ; Klinefelter Syndrome/pathology* ; Retrospective Studies ; Seminiferous Tubules/pathology* ; Biopsy

Klinefelter syndrome (KS) is one of the most frequent genetic abnormalities and the leading genetic cause of nonobstructive azoospermia. The breeding and study of KS mouse models are essential to advancing our knowledge of the underlying pathological mechanism. Karyotyping and fluorescence in situ hybridization are reliable methods for identifying chromosomal contents. However, technical issues associated with these methods can decrease the efficiency of breeding KS mouse models and limit studies that require rapid identification of target mice. To overcome these limitations, we developed three polymerase chain reaction-based assays to measure specific genetic information, including presence or absence of the sex determining region of chromosome Y (Sry), copy number of amelogenin, X-linked (Amelx), and inactive X specific transcripts (Xist) levels. Through a combined analysis of the assay results, we can infer the karyotype of target mice. We confirmed the utility of our assays with the successful generation of KS mouse models. Our assays are rapid, inexpensive, high capacity, easy to perform, and only require small sample amounts. Therefore, they facilitate the breeding and study of KS mouse models and help advance our knowledge of the pathological mechanism underlying KS.
Animals ; Azoospermia ; In Situ Hybridization, Fluorescence ; Karyotyping ; Klinefelter Syndrome/genetics* ; Mice ; Polymerase Chain Reaction

This retrospective study demonstrates the clinical outcomes of patients with nonmosaic Klinefelter's syndrome (KS) who underwent preimplantation genetic testing (PGT) with frozen-thawed testicular spermatozoa. Microdissection testicular sperm extraction (micro-TESE) was performed for sperm retrieval. Next-generation sequencing (NGS) was conducted for embryo analysis. A total of 18 couples aged ≤35 years were included, and 22 oocyte retrieval cycles were completed. Euploidy was detected in 29 of 45 (64.4%) embryos. Additionally, the numbers of aneuploid and mosaic embryos detected were 8 (17.8%) and 8 (17.8%), respectively, regardless of a lack of sex chromosome abnormalities. Finally, 13 couples with euploid embryos completed 14 frozen embryo transfer (FET) cycles. Ten couples had clinical pregnancies, and 6 of them had already delivered 5 healthy babies and 1 monozygotic twin. There were also 4 ongoing pregnancies and 2 biochemical pregnancies, but no early pregnancy loss was reported. Based on our results, we speculate that for KS patients, when sperm can be obtained by micro-TESE, the cryopreservation strategy makes the ovarian stimulation procedure more favorable for female partners. The paternal genetic risk of sex chromosome abnormalities in their offspring is extremely low in men with KS. In addition to PGT, the intracytoplasmic sperm injection (ICSI) procedure is comparably effective but more economical for young nonmosaic KS couples. ICSI should be offered as an option for such couples, but monitoring by prenatal genetic diagnosis is recommended.
Adult ; Female ; High-Throughput Nucleotide Sequencing/methods* ; Humans ; Klinefelter Syndrome/therapy* ; Outcome Assessment, Health Care/statistics & numerical data* ; Ovulation Induction/statistics & numerical data* ; Pregnancy ; Retrospective Studies ; Sperm Injections, Intracytoplasmic/methods*

Female ; Fertilization in Vitro ; Humans ; Klinefelter Syndrome/genetics* ; Pregnancy ; Preimplantation Diagnosis ; Sperm Injections, Intracytoplasmic

Hidradenitis suppurativa (HS) is a chronic, inflammatory and painful skin disease with recurrent nodules and tracts involving the intertriginous regions. It is known that the patient with HS shows an increased risk of metabolic disorders such as diabetes, metabolic syndrome and autoimmune diseases. Klinefelter syndrome (KS) is a sex chromosomal disorder occurring in males due to an abnormality of sexual differentiation, characterized by 47, XXY karyotype. Also, KS is related with somatic comorbidities such as metabolic syndrome, autoimmune and rheumatologic disorders as HS is. We report a HS patient with KS who shows a big improvement while on tumor necrosis factor-alpha inhibitor treatment.
Adalimumab ; Autoimmune Diseases ; Chromosome Disorders ; Comorbidity ; Hidradenitis Suppurativa ; Hidradenitis ; Humans ; Karyotype ; Klinefelter Syndrome ; Male ; Sex Differentiation ; Skin Diseases ; Tumor Necrosis Factor-alpha

Klinefelter syndrome (KS) is characterized by small testes, gynecomastia, tall stature, and hypergonadotropic hypogonadism. This condition is associated with extra X chromosomes. It is well known that these aneuploidies predispose individuals to the development of several cancers. Moreover, there are many case reports that show KS patients to have a higher relative risk for the development of malignancy. However, incracranial germ cell tumor (ICGCT) associated with KS is very uncommon. Herein, we report delayed diagnosis of KS in a 15-year-old boy with ICGCT, embryonal carcinoma of the pineal gland, after multimodality treatment in Korea.
Adolescent ; Aneuploidy ; Carcinoma, Embryonal ; Delayed Diagnosis ; Gynecomastia ; Humans ; Hypogonadism ; Klinefelter Syndrome ; Korea ; Male ; Neoplasms, Germ Cell and Embryonal ; Pineal Gland ; Testis ; X Chromosome