Congenital deficiency of factor XIII with normal subunit S and lack of subunit A. Report of a new family.

Two sisters born from a nonconsanguineous marriage were found to have congenital factor XIII deficiency. In the electroimmunoassay system, using an anti-subunit S antiserum, two distinct peaks or rockets were seen in normal plasma and serum whereas only one peak was present in the propositae plasma or serum. In the bidimensional immunoelectrophoresis system, using the anti-subunit S antiserum, two major peaks were seen in normal plasma whereas only one peak was seen in the propositae plasma. Using an anti-subunit A antiserum no peak or precipitate was seen in our propositae in the electroimmunoassay or in the bidimensional immunoelectrophoresis systems. Both the parents and the children of our two propositae showed a normal coagulation pattern. Therefore, the heredity appears to be autosomal recessive. These data indicate that the defect is characterized by a normal factor XIII subunit S (support) and a lack of factor XIII subunit A (activity).