Introduction. Inherited thrombophilia is described to be the most frequent reason for ischemic stroke in infants and toddlers (PedAIS). But the certain role of some thrombophilia related genes is not investigated thoroughly.  
Methods. Case-control study. 54 patients’ blood samples with PedAIS debut at 0-24 month (including fetal and perinatal type of PedAIS), confirmed by brain MRI were compared with 117 controls. 4 single nucleotide polymorphisms (SNPs) of folic acid enzymes genes MTR: 2756 А>G, МТRR: 66А>G, MTHFR: 677 С>Т, MTHFR: 1298 А>С were investigated by polymerase chain reaction. 
Results. There were no differences in MTHFR: 1298 А>С and 677С>Т  carriage in both groups. We sorted out all the SNPs combinations and found those 8 significant raised the risk of PedAIS’s with early-life onset (table contains combinations based on 3 SNPs). MTRR: 66 А>G + MTHFR: 1298 А>С (n=34, OR=4.33, 95%CI 2.15-8.69, p<0,000) and MTRR: 66 А>G + MTHFR: 677 С>Т (n=33 OR=5.24, 95%CI 2.57-10.66, p<0,000) are the most common SNP combinations in PedAIS group. Only PedAIS patients had four SNPs combination (MTR: 2756 А>G + МТRR: 66А>G + MTHFR: 677 С>Т + MTHFR: 1298 А>С, n=5). 

Forecast value of of folic acid enzymes SNPs in toddlers with PedAIS
SNP combinations
	Control group, n=117, abs	PedAIS, n=54, abs	OR	95%CI	Fisher
МТRR: 66А>G + MTHFR: 677 С>Т + MTHFR: 1298 А>С	5	16	9.43	3.17-28.09	0.000
MTR: 2756 А>G + МТRR: 66А>G + MTHFR: 677 С>Т	5	10	5.09	1.61-16.11	0.004
MTR: 2756 А>G + МТRR: 66А>G + MTHFR: 1298 А>С	6	10	4.20	1.41-12.54	0.007
*- calculation took into account both hetero- and homozygous (not wild) alleles.

Conclusion. Folic acid enzymes genes SNPs must be taken into account as the important risk factor for early life stroke’s debut. Carriage of 2-3 SNPs combination seems to increase the risk of PedAIS onset in 4-5 times in the age under 2 years old.

ARTERIAL ISCHEMIC STROKE IN INFANTS AND TODDLERS: THE SIGNIFICANCE ASSESSMENT AND PROGNOSTIC CAPABILITY OF CARRIAGE POLYMORPHISMS IN FOLIC ACID ENZYMES GENES