Association of methylenetetrahydrofolate reductase A1298C mutation with normal homocysteine level: A rare cause of cerebral venous sinus thrombosis in an infant

Abstract Inherited causes of cavernous venous sinus thrombosis (CVST) leading to stroke in infancy are rare. Methylenetetrahydrofolate reductase (MTHFR) gene mutation is one such cause. Polymorphism of MTHFR, an essential enzyme in Vitamin B12 metabolism, leads to an increase in homocysteine levels. This is a prothrombotic state and, therefore, causes pediatric stroke. Children with a mutation of the MTHFR gene have elevated homocysteine levels. The index case of MTHFR polymorphism with CVST leading to stoke had a normal homocysteine level. The association of MTHFR A1298C mutation with CVST can be confirmed only after further studies, as the role of heterozygous A1298C mutation in prothrombotic state is conflicting.