[Importance of Klinefelter syndrome in the pathogenesis of male infertility]

Rev Med Chir Soc Med Nat Iasi. 2007 Apr-Jun;111(2):373-8.
[Article in Romanian]


Klinefelter syndrome, the most knowning hipergonadotrophic hypogonadism, is associated typically with two X chromosomes and one Y chromosome (47,XXY. The signs and symptoms of these conditions typically become more severe as the number of X chromosomes increases.

Aim: To preveal the role of Klinefelter syndrome in pathogenesis of male infertility.

Material and methods: The study included 20 men hospitalized and treated in the Endocrinology Clinic, Iaşi. The age of patients was between 19 years and 44 years. They made next investigations: clinical, biological and semen examination, testis echography and biopsy, test Elisa, Barr's test, psychological evaluation and psycho-analysis. Diagnosis of Klinefelter syndrome is made by examining chromosomes for evidence of more than one X chromosome present in a male.

Results: All patients are characterized by chromosomal abnormalities, small penis, small firm testicles with hyalinization and fibrosis of the seminiferous tubules, underdevelopment of secondary sexual characteristics, abnormal body proportions (long legs, short trunk), sexual problems, azoospermia, infertility and increased urinary excretion of gonadotropin. 14 cases had gynecomastia and 2 cases presented anti-sperm antibodies. The following test results may be found: karyotyping chromosome shows 47 XXY; positive test Barr; semen count-low; serum testosterone- low; serum luteinizing hormone (LH)--high; serum follicle stimulating hormone (FSH)--high; serum estradiol levels (a type of estrogen)-high, testicle size measurement < 10 cc.

Conclusions: Klinefelter syndrome is a chromosomal condition that affects male sexual development, preventing the testicles from functioning normally and reducing the levels of testosterone. Low Testosterone can lead to breast development (gynecomastia), decreased libido, incomplete masculinization with female body hair distribution (sparse facial, armpit, and pubic hair) and an inability to father children (infertility). The decreased testosterone also causes an increase in two other hormones, follicle stimulating hormone (FSH) and luteinizing hormone (LH). The increased amount of FSH and LH cause hyalinization and fibrosis, the growth of excess fibrous tissue, in the seminiferous tubules, where the sperm are normally located. As a result, the testicles appear smaller and firmer than normal. Men with Klinefelter syndrome are infertile because they cannot make sperm. Testosterone therapy may help to produce more normal development including more muscle mass, hair growth and increased sex drive. Testosterone supplementation will not increase testicular size, decrease breast growth or correct infertility. There is no treatment available to change chromosomal makeup.

Publication types

  • English Abstract

MeSH terms

  • Adult
  • Biomarkers / blood
  • Estradiol / blood
  • Follicle Stimulating Hormone / blood
  • Humans
  • Infertility, Male / blood
  • Infertility, Male / diagnosis*
  • Infertility, Male / genetics*
  • Karyotyping
  • Klinefelter Syndrome / blood
  • Klinefelter Syndrome / complications*
  • Klinefelter Syndrome / diagnosis*
  • Klinefelter Syndrome / genetics
  • Luteinizing Hormone / blood
  • Male
  • Oligospermia / genetics
  • Oligospermia / pathology
  • Testosterone / blood
  • Testosterone / therapeutic use
  • Treatment Outcome


  • Biomarkers
  • Testosterone
  • Estradiol
  • Luteinizing Hormone
  • Follicle Stimulating Hormone