Cystathionine beta-synthase (CBS) is an enzyme that plays a crucial role in the metabolism of the amino acid homocysteine. It catalyzes the conversion of homocysteine and serine into cystathionine, which is a precursor for the synthesis of cysteine, another important amino acid. This process is vital for maintaining proper levels of homocysteine in the body. Deficiencies or mutations in the CBS gene can lead to a condition known as cystathionine beta-synthase deficiency, which can result in elevated homocysteine levels. This condition may cause various health issues, including cardiovascular problems and developmental delays. Proper functioning of CBS is essential for overall health and amino acid balance.