title: [Cystathionine betasynthase and MTHFR deficiencies in adults].
abstract: BACKGROUND
  Homocysteine lies at an important metabolic branch point; it may be either converted to cystathionine through the transsulfuration pathway, or methylated to form methionine. Hyperhomocysteinemia may result from hereditary defects affecting one of these reactions.
  
  
  BACKGROUND
  Cystathionine beta synthase or 5,10-methylenetetrahydrofolate deficiency can both result in homocystinuria. Current knowledge about biochemical mechanisms leading to hyperhomocysteinemia, clinical and radiological features, pathogenesis and treatment are reviewed, focusing on late onset forms of these diseases which can be diagnosed in adulthood. CBS deficiency is characterized by lens dislocation, skeletal abnormalities, neurologic disturbances and thromboembolism. MTHFR deficiency leads to various neurological symptoms, ranging from developmental delay to encephalopathy, including motor and gait abnormalities, seizures, psychiatric manifestations and rarely strokes. The treatment of CBS deficiency depends on vitamin B6, whereas MTHFR deficiency can be efficiently treated by vitamin B12, folic acid, and betaine.
  
  
  CONCLUSIONS
  Homocysteinemia should be measured in patients with unexplained neurological manifestations or thromboembolism.
authors.affiliation: Fédération des maladies du système nerveux, Groupe Hospitalier Pitié-Salpétrière, Paris.
authors.forename: F
authors.initials: F
authors.lastname: Cohen Aubart
authors.forename: F
authors.initials: F
authors.lastname: Sedel
authors.forename: T
authors.initials: T
authors.lastname: Papo
mesh_terms: D000818:Animals; D005492:Folic Acid / Q000097:blood; D006710:Homocysteine / Q000097:blood / Q000378:metabolism; D006712:Homocystinuria / Q000175:diagnosis / Q000235:genetics / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D008279:Magnetic Resonance Imaging; D009422:Nervous System Diseases / Q000175:diagnosis / Q000209:etiology / Q000235:genetics / Q000628:therapy; D013762:Tetrahydrofolate Dehydrogenase / Q000172:deficiency* / Q000235:genetics
chemical_list: D006710:Homocysteine; D005492:Folic Acid; D013762:Tetrahydrofolate Dehydrogenase