Klinefelter Syndrome (KS) is a relatively common (1/500 to 1/1,000) genetic syndrome caused by an extra X chromosome in males, leading to an XXY karyotype. In most cases, the physical and neurobehavioral characteristics of KS are relatively mild, and KS is not usually associated with moderate or severe mental retardation. However, KS is often associated with significant language-based learning ...

The Klinefelter syndrome (KS), with an incidence of 1 to 2 per 1000 male neonates, is one of the most frequent congenital chromosome disorders. The 47,XXY karyotype causes infertility, testosterone deficiency and a spectrum of further symptoms and comorbidities. In recent years, significant progress has been made in the elucidation of the pathophysiology and the treatment of the KS. It became c...

The presence of an isochromosome Xq in Klinefelter syndrome (KS) is an apparently rare condition. In all cases reported so far, patients showed the classic phenotype. We here describe a case of isochromosome Xq [47,X,i(Xq),Y] in a non-mosaic KS patient. The patient exhibited a normal androgenized phenotype, normal testes and normal cognitive abilities. Semen analysis revealed a medium oligozoos...

OBJECTIVES To characterize associations among psychosocial well-being, physical phenotype, and sex hormones in a sample of youth with Klinefelter syndrome (KS). We hypothesized that KS physical traits (phenotype) are associated with adverse psychosocial health measures and that testosterone levels are associated with adverse psychosocial health. STUDY DESIGN Forty-three boys with KS (ages 8-1...