Summary

A 17-year old man was sent to us for coagulation testing because he suffered from acute bleeding which started immediately after making an incision in the skin for a urological surgery. The patient had a history of mild bleeding symptoms (nose bleeds during the childhood, gingival bleeds). Results of laboratory investigations: Blood group 0, closure times (PFA 100):132 s (ADP/collagen) and 300 s (epinephrine/collagen), VWF antigen 57%, VWF activity 50%, factor VIII activity 66%, factor XIII activity 59%. The results were confirmed by further investigations. Additionally, two relevant genetic findings were obtained: first a heterozygous base exchange in exon 11 of the factor 13A gene -Thr 449 (ACT)>Ile (ATT)-, not described before the completion of the study, and second the homozygous state of the 807 C-allele within the integrin α2 gene. The patient inherited the base exchange in the factor 13A gene from his mother. Homozygosity of the 807 C allele in the integrin α2 gene is associated with a very low expression of the platelet collagen receptor. Individuals with low VWF due to blood group 0 and low platelet collagen receptor density often exhibit a bleeding tendency, e.g. bleedings from mucosal membranes or menorrhagia in females. Conclusion: In our opinion the light factor XIII deficiency in our patient is coincidental and not the sole cause of bleeding.