Hereditary alpha 2-macroglobulin deficiency.

On screening of a normal material 1 man was found (age 37) who on repeated determinations had a low alpha 2M, namely 25 % with electroimmuno assay according to Laurell. Investigation of the family revealed that the mother (age 69) and one daughter (age 5) had low values too. All other coagulation and fibrinolytic components were normal. They had no signs of increased fibrinolysis and normal levels of alpha 2-antiplasmin, alpha 1-antitrypsin and antithrombin III. Liver function tests were normal. It seems to be an inherited deficiency. The transmission is apparently autosomal dominant and the affected members heterozygotes. The defect has not caused any clinical symptoms. This family appears to be the first reported with an alpha 2M deficiency.