Disease Information for Homocystinuria/homocystinemia (Clinical Manifestations)

cystathionine synthase deficiency, HOMOCYSTINURIA, Homocystinuria (disorder)

There are several different types of homocystinuria, but they all occur when the body lacks an enzyme needed to break down (metabolize) protein; When the enzyme is missing, part of the protein called “homocysteine” builds up in the body and causes damage to the nervous system (including the brain) and to the vascular system; The most common problems seen in people with homocystinuria include dislocation of the lenses of the eye, osteoporosis, and blood clots; If untreated, homocystinuria can lead to mental retardation and even death; There are several amino acids involved in all types of homocystinuria; The first is methionine; Methionine is broken down into a second amino acid called homocysteine; The body then breaks down the homocysteine to make yet a third amino acid called cysteine; some patients are unable to break down the homocysteine into cysteine because they do not have enough of an enzyme called cystathionine-beta-synthase (CBS); Not having enough CBS causes the levels of homocysteine to build up in the blood and the levels of cysteine to drop resulting in damage to the body; Homocystinuria is an inherited disorder; The mode of inheritance is autosomal recessive; The condition can affect both males and females; <br>

Infants, children and even adults that exhibit symptoms of homocysteinuria can be identified with a simple blood test that measures the amount of homocysteine in the blood; Further testing measuring the amount and type of enzyme activity is done to confirm the diagnosis; The goal of treatment for homocystinuria is to keep the level of homocysteine in the blood as consistently low as possible; This will help prevent many of the problems caused by having high levels; The treatment itself consists of four main parts: diet, formula, supplements, monitoring; Some with homocysteinuria must cut down on the amount of protein that they eat in order to lower their homocysteine levels; People with homocystinuria who must avoid foods high in protein must also must also learn what foods have some amount of protein and ways to measure how much; Some individuals, depending on the severity of their disorder, are given a daily limit of the protein they can eat; All need homocysteine for growth and development; The trick is not to eat too much; This is done by learning to count and keep track of the amount they consume throughout the day tracking both methinonine rich and other protein amounts;<br>

Formula for those people who must avoid foods high in protein, the second part of the treatment for homocystinuria requires a special protein formula; Some forms of homocystinuria can be treated with high doses of one of the B-vitamins called pyridoxine (vitamin B6); Vitamin B6 is a co-factor that helps the CBS enzyme work better; Other cofactors, Vitamin B12 and Folic Acid, may also help; Another supplement used to lower homocysteine levels is Betaine (also known as Cystadane); Betaine combines with homocysteine to change it back to methionine which can then be used for other functions in the body;<br>

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--[Kaiser permanente website 2006]----------------------<br>

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