What is Cystathionine Beta-Synthase C699T Polymorphism?
Cystathionine beta-synthase shunts homocysteine into the transsulphuration pathway for synthesis of cysteine and downstream glutathione production. The C699T polymorphism has been reported to increase CBS activity in some functional contexts, potentially lowering homocysteine but raising downstream sulphite, sulphate, and ammonia. Classical CBS deficiency (a separate, rare autosomal-recessive disorder) causes severe homocystinuria; the C699T variant does not.