Cystathionine beta synthase deficiency
There is no cure for homocystinuria. However, many people respond to high doses of vitamin B6 (also known as pyridoxine). Slightly less than half of patients respond to this treatment.
Those who do respond will need to take vitamin B6 supplements for the rest of their lives. Those who do not respond need to eat a low-methionine diet. Most will need treatment with trimethylglycine (a medication also known as betaine).
Neither a low-methionine diet nor medication will improve existing mental retardation. Medication and diet should be closely supervised by a physician with experience treating homocystinuria.
A normal dose folic acid supplement and added cysteine (an amino acid) in the diet are helpful.
Although no cure exists for homocystinuria, vitamin B6 therapy can help about half of people affected by the condition.
If the diagnosis is made while a patient is young, starting a low methionine diet quickly can prevent some mental retardation and other complications of the disease. For this reason, some states screen for homocystinuria in all newborns.
Patients with persistent rises in blood homocysteine levels are at increased risk for blood clots. Clots can cause significant medical problems and shorten lifespan.
Most serious complications result from blood clots. These episodes can be life threatening.
Dislocated lenses of the eyes can severely impair vision. Lens replacement surgery should be considered.
Mental retardation is a serious consequence of the disease. However, it can be lessened if diagnosed early.
Call your health care provider if you or a family member shows symptoms of this disorder, particularly if there is a family history of homocystinuria. Also call if you have a family history and are planning to have children.
Rezvani I. Defects in metabolism of amino acids. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 85.
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