The cystathionine beta synthase (CBS) enzyme converts homocysteine
to cystathionine. The two most common mutations in the CBS gene are
the G919A and T833C substitutions resulting in a serine for glycine at
amino acid residue 307 and a threonine for isoleucine at amino acid 278,
Patients with the T833C mutation can respond to pyridoxine therapy,
whereas, patients with the G919A mutation do not respond to pyridoxine
therapy. Thus, identification of these CBS mutations would help in the
diagnosis and treatment of homocysteinemia.
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deficiency: report of a new mutation in exon 8 and a deletion in intron 11.
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