What karyotype is Klinefelter's syndrome associated with?

47, XXY

What are the main clinical features of Klinefelter's syndrome?

• often taller than average
• lack of secondary sexual characteristics
• small, firm testes
• infertile
• gynaecomastia - increased incidence of breast cancer

What results would be found on testing sex hormones in Klinefelter's syndrome?

elevated gonadotrophin levels but low testosterone

How is Klinefelter's syndrome disagnosed?

by karyotype (chromosomal analysis)