Klinefelter’s Syndrome

Klinefelter’s Syndrome is a chromosomal disorder in men, characterized by an extra X chromosome, no sperm in the ejaculate or a low sperm count in the semen. Klinefelter's is a genetic disorder. Sperm may still be produced in the testes and can be retrieved for use with IVF with ICSI. However, this is an inherited condition and these patients should consult with a genetic counselor prior to attempting conception since some of the sperm will pass along an extra X chromosome. Chromosomal testing of the embryos is one option to enable these couples to have healthy children.


Several physical symptoms such as small testes and small penis can suggest Klinefelter’s is present. Excess gonadotropins - hormones that in men stimulate testicular function - is another symptom of the condition. Children with Klinefelter’s may be slow learners and be tall and thin.


An extra X chromosome (XXY instead of XY) causes Klinefelter's.


Men with this syndrome usually require fertility treatment to have children. The focus of treatments is not to correct the syndrome, but to harvest any sperm the man has for use in assisted reproductive procedures such as intracytoplasmic sperm injection (ICSI). If this is not possible, donor sperm is another option.

Approximately 7% of infertile men have some form of chromosomal abnormality. 10-15% of men with azoospermia (absence of sperm) will have an abnormality, compared to 3–7% of men with oligospermia (low sperm count).

Chromosomal abnormalities can be inherited, so the couple should have genetic counseling to understand the risk of passing this on to their offspring.

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