Dr. med. Dirk Manski

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Klinefelter Syndrome

Review literature: (Lanfranco et al., 2004).

Definition of Klinefelter Syndrome

Klinefelter syndrome is the most common sex chromosome disorder and results in primary hypogonadism and infertility in men. The syndrome is caused by an additional X chromosomes resulting in a karyotype of 47,XXY.

Synonyms: XXY syndrome, 47,XXY males,

Epidemiology of Klinefelter Syndrome

Prevalence in men 1:500–1000, less than 50% of affected patients are diagnosed.

Causes (Etiology) and Pathology of Klinefelter Syndrome

The karyotype of Klinefelter syndrome is 47,XXY. Also possible karyotypes are 46,XY/47,XXY mosaic. The cause of the sex chromosome disorder is a defect of meiosis during gametogenesis, meiotic defects of the zygote cause Klinefelter syndrome with mosaic karyotype.

Klinefelter syndrome results in a sclerosis of the seminiferous tubules, missing or severely damaged spermatogenesis and hyperplasia of Leydig cells.

Signs and Symptoms

Diagnostic Workup in Klinefelter Syndrome

Klinefelter syndrome should be suspected if azoospermia, hypergonadotropic hypogonadism and the above mentioned phenotype are present.

Treatment of Klinefelter Syndrome

Index: 1–9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z


Lanfranco u.a. 2004 LANFRANCO, F. ; KAMISCHKE, A. ; ZITZMANN, M. ; NIESCHLAG, E.: Klinefelter’s syndrome.
In: Lancet
364 (2004), Nr. 9430, S. 273–83

  Deutsche Version: Klinefelter-Syndrom