Two patients with generalized bleeding tendencies due to congenital factor XIII deficiency are described. Their initial bleeding episode was umbilical bleeding in early neonatal period which was characteristic of bleeding of the disease. After that, bleeding in subcutaneous tissue, muscle and oral cavity were frequently observed in their clinical courses.
Coagulation studies revealed the reduction of ma in thrombelastogram and increased solubility of patients' clot in 1% monochloracetic acid. The activity of factor XIII of first patient's plasma was 2.5% and his levels of subunit a and b were 0% and 45% respectively. The activity of factor XIII of second patient's plasma was 1.5% and his levels of subunit a and b were 0% and 45% respectively. The activity and subunit a of factor XIII of both patients' platelets were deficient. Both first patient's parent and second patient's parent are considered heterozygous carriers, because the assay of factor XIII of their plasma revealed the increase of subunit b/a of the factor.
