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Homocystinuria due to CBS deficiency

Other Names for this Disease
  • CBS deficiency
  • Cystathionine beta-synthase deficiency
  • Homocystinuria due to cystathionine beta-synthase deficiency
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Homocystinuria due to CBS deficiency is an inherited disorder in which the body is unable to process certain building blocks of proteins (amino acids) properly. This form of homocystinuria is caused by the lack of an enzyme called cystathionine beta-synthase, which results from a mutation in the CBS gene. It is characterized by dislocation of the lens in the eye, an increased risk of abnormal blood clots, and skeletal abnormalities. Problems with development and learning are also evident in some cases. Homocystinuria due to CBS deficiency is inherited in an autosomal recessive pattern.[1] Treatment aims to correct the biochemical abnormalities, especially to control blood homocystine concentration and prevent thrombosis (blood clots). Vitamin B6 (pyridoxine) therapy, protein-restricted and methionine-restricted diets, betaine treatment, and/or folate and vitamin B12 supplementation may be used to manage the condition.[2]

Last updated: 3/16/2011


  1. Homocystinuria. Genetics Home Reference (GHR). 2008; Accessed 3/16/2011.
  2. Picker JD, Levy HL. Homocystinuria Cuased by Cystathionine Beta-Synthase Deficiency. GeneReviews. 2006; Accessed 3/16/2011.
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Basic Information

  • Genetics Home Reference (GHR) contains information on Homocystinuria due to CBS deficiency. This website is maintained by the National Library of Medicine.
  • The Screening, Technology And Research in Genetics (STAR-G) Project has a fact sheet on this condition, which was written specifically for families that have received a diagnosis as a result of newborn screening. This fact sheet provides general information about the condition and answers questions that are of particular concern to parents.

In Depth Information

  • Medscape Reference provides information on this topic. Click on the link to view this information. You may need to register to view the medical textbook, but registration is free.
  • The Online Mendelian Inheritance in Man (OMIM) is an catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs.  Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Homocystinuria due to CBS deficiency. Click on the link to view a sample search on this topic.