{'fraction_non_alphanumeric': 0.0270848182466144, 'fraction_numerical': 0.009265858873841768, 'mean_word_length': 5.591549295774648, 'pattern_counts': {'":': 0, '<': 1, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Thrombotic Events in Asymptomatic FXII Deficiency versus Symptomatic FXI Deficiency: Surprising Observations

Objective: To evaluate the impact of an asymptomatic congenital clotting defect (FXII deficiency) versus that of a similar but symptomatic defect (FXI deficiency) on protection from thrombosis. Patients and Methods: All patients with FXII or FXI deficiency and thrombosis were gathered from a time-unlimited PubMed search that was carried out twice and from personal records. Combined defects were excluded. The defect had to be proven by the demonstration of a suited hereditary pattern and by a specific clotting assay. Only patients with a factor activity level of <30% of normal were selected. Results: Twenty-eight patients with an FXII deficiency presented with arterial thrombosis, mainly myocardial infarction, and 29 showed venous thrombosis; for FXI deficiency, these figures were 43 and 10, respectively. The ratio of arterial and venous thrombosis was 0.96 and 4.3, respectively, for FXII and FXI deficiency. Conclusions: Factor FXII deficiency supplies no protection from arterial or venous thrombosis. FXI deficiency shows no protection from arterial thrombosis but appears to guarantee protection from venous thrombosis. A symptomatic, namely bleeding, condition (FXI deficiency) provides protection from venous thrombosis whereas an asymptomatic one (FXII deficiency) does not.