High seminal sialic acid concentrations in patients with severe teratozoospermia.

Seminal plasma and sperm-bound sialic acid (SA) concentrations were evaluated in patients with severe teratozoospermia (< 5 % morphologically normal sperm) and correlated with values of a control group with > 20% morphologically normal sperm. The SA concentrations both in seminal plasma and on sperm were significantly higher in teratozoospermia, but the ratio of sperm-bound SA to seminal plasma SA remained virtually the same. The causes and consequences of high SA in these patients need further study.