File:Klinefelter syndrome karyotype.jpg

Klinefelter's syndrome (47,XXY)

47, XXY Affects approximately one in every 660 men who begin normal male and become infertile. Features: tall, mental dullness, narrow shoulders, broad hips, sparse body hair, gynecomastia, small testicles, androgen deficiency, azoospermia, behaviour problems and decreased verbal intelligence.

The syndrome was named after Dr. Harry Klinefelter, an endocrinologist at Massachusetts General Hospital in Boston, Massachusetts, who first described it in 1942.

Klinefelter, HF Jr; Reifenstein, EC Jr; Albright (1942), "Syndrome characterized by gynecomastia, aspermatogenesis without a-Leydigism and increased excretion of follicle-stimulating hormone", J Clin Endocrinol Metab 2: 615–624. Klinefelter, HF (1986), "Klinefelter's syndrome: historical background and development", South Med J 79 (45): 1089–1093, [PMID: 3529433]