Mannan binding lectin concentration and risk of miscarriage.

Recurrent miscarriage is associated with low concentrations of mannan-binding lectin (MBL), but it is not known below which value relative MBL deficiency becomes a significant risk factor. The sera of 397 patients (male and female) suffering from recurrent miscarriage and 376 controls were assayed for MBL and the data analysed. It was found that the lower the cut-off value, the greater the statistical strength of the association. It was concluded that only MBL concentrations </=0.1 microg/ml were clinically significant in this context. A corollary of this conclusion is that genotyping for point mutations in the structural gene for MBL would be a much less sensitive means of identifying couples at risk of experiencing recurrent miscarriage.