ABSTRACT
Cryptogenic stroke means stroke with unexplained aetiology, in many cases the cause of stroke remains undetermined in spite of full investigations. Those patients are thought to have hypercoagulable state, the purpose of study is to unmask some of the pathogenic mechanisms underlying cryptogenic stroke through assessment of some genetic disorders including C677T mutation in methylenetetrahydrofolate reductase gene and activated protein C [APC] resistance, and the role of thrombin anti-thrombin complex concentration in plasma as indicator of hypercoagulable state. The study is case-control study that was conducted on 20 Egyptian patients who were classified into 2 groups; group I includes 10 patients with cryptogenic stroke who are less than 50 years and group II that includes 10 age and sex-matched patients with non-cryptogenic stroke. They were subjected to a panel of investigations including all routine labs and imaging studies in order to exclude any conventional risk factors for stroke in group I patients and to determine the risk factors for stroke in group II, then both groups are investigated for C677T mutation in methylenetetrahydrofolate reductase gene, activated protein C [APC] resistance and thrombin anti-thrombin complex concentration in plasma. Revealed no statistical significant difference was found between the two groups as regard C677T mutation in methylenetetrahydrofolate reductase gene, activated protein C [APC] resistance, and thrombin anti-thrombin complex concentration [TAT] in plasma [P value >0.05], TAT level was positively correlated with clinical severity in non-cryptogenic stroke [P value <0.05]. C677T mutation in methylenetetrahydrofolate reductase gene, activated protein C [APC] resistance and thrombin anti-thrombin complex concentration in plasma are not independent risk factors for cryptogenic stroke, thrombin anti-thrombin complex concentration [TAT] could be used as indicator of clinical severity and prognosis in patients with non-cryptogenic stroke