cystathionine β-synthase deficiency

cys·ta·thi·o·nine β-syn·thase de·fi·cien·cy (sis″tə-thiґo-nēn sinґthās) an autosomal recessive aminoacidopathy caused by mutations in the CBS gene (locus: 21q22.3), which encodes cystathionine β-synthase, characterized by homocystinuria accompanied by hypermethioninemia. Clinical abnormalities occur primarily in the eye and the skeletal, nervous, and vascular systems; ectopia lentis, osteoporosis, mental retardation, and thrombosis are the most common manifestations. In older literature, the disorder is sometimes called homocystinuria (q.v.).