Article Title: From mini‐puberty to pre‐puberty: early impairment of the hypothalamus-pituitary-gonadal axis with normal testicular function in children with non-mosaic Klinefelter syndrome

Authors: Spaziani, Granato, Liberati, Rossi, Tahani, Pozza, Gianfrilli, Papi, Anzuini, Lenzi, Tarani, and Radicioni

Date of Publication: May 6, 2020

“Purpose Klinefelter syndrome (KS) is a genetic disorder caused by the presence of an extra X chromosome in males. The aim of this study was to evaluate the hypothalamic–pituitary–gonadal (HPG) axis and the clinical profile of KS boys from mini-puberty to early childhood…Conclusions No hormonal signs of tubular or interstitial damage were found in KS infants. The presence of higher levels of gonadotropins, INHB and testosterone during mini-puberty and pre-puberty may be interpreted as an alteration of the HPG axis in KS infants.”

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Article Title: Klinefelter syndrome (KS): genetics, clinical phenotype and hypogonadism

Authors: Bonomi, Rochira, Pasquali, Balercia, Jannini, and Ferlin

Date of Publication: September 19, 2016

“Klinefelter Syndrome (KS) is characterized by an extreme heterogeneity in its clinical and genetic presentation. The relationship between clinical phenotype and genetic background has been partially disclosed; nevertheless, physicians are aware that several aspects concerning this issue are far to be fully understood. By improving our knowledge on the role of some genetic aspects as well as on the KS, patients’ interindividual differences in terms of health status will result in a better management of this chromosomal disease. The aim of this review is to provide an update on both genetic and clinical phenotype and their interrelationships.”

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Article Title: Strategies to improve early diagnosis of Klinefelter syndrome

Authors: Alberto Ferlin

Date of Publication: October 2020

“Klinefelter syndrome is the most frequent chromosome disorder in men, but it is largely undiagnosed or receives a late diagnosis in adulthood. This condition is characterized by an extra X-chromosome: approximately 80%-90% of patients with Klinefelter syndrome have a 47,XXY karyotype, 10%-20% mosaicisms of two different genetic lines such as 47,XXY/46,XY, isochromosome X, and higher number of X chromosomes. Although our knowledge on this syndrome substantially improved in last years, the diagnostic rate is still low. It has been estimated that only 25% to 40% of subjects with 47,XXY Klinefelter syndrome are ever diagnosed. A prenatal diagnosis is made in 15–20% of these cases, 10% is diagnosed before puberty, 15% at puberty, and the remaining 50–60% of cases are diagnosed during adulthood, typically in the course of a fertility workup, with some cases diagnosed even after the age of 50 or 60 years. Variants with higher number of X chromosomes (48,XXXY and 49,XXXXY) have more severe phenotype and distinct clinical features, which leads to higher diagnostic rate than 47,XXY. This manuscript refers to the most common form 47,XXY syndrome and strategies to improve early and timely diagnosis.”

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