Homocystinuria

= Homocystinuria = toc

Jody and Liz

What is Homocystinuria?
Also known as [|Cystathionine beta synthase](CBS) deficiency, this rare, inherited metabolic disease involves the CBS enzyme, and the methionine (MET) amino acid of the CBS gene. The CBS enzyme is what catalyzes the [|transsulfuration] pathway between [|homocysteine] and [|cystathionine.] It occurs when elevated amounts of homocysteine are present in the urine and in the blood.

Symptoms of Homocystinuria [[image:Summer10-MarfanSyndrome.jpg width="129" height="221" align="right"]][[image:ectopialentis width="294" height="135" align="right"]]
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 * tall, thin and long limbed
 * high arched feet
 * hollow
 * Pigeon chest
 * mental retardation
 * seizures
 * [|ectopia lentis] (crystalline lens misplaced)

Genetics of Homocystinuria
= = The genes that are mutated during homocystinuria are [|Cystathionine beta Synthase](CBS),[| MTHFR], [|MTR], and [|MTRR].

__** The Process: **__

The CBS geme is in charge of making the enzyme [|Cystathionine beta Synthase], which is needed for the Transsulfuration pathway. This metabolic pathway is responsible for making MET(Methionine) and to do this, it must convert homocysteine into cysteine. Without the CBS enzyme, this pathway cannot execute its proper functions, thus causing a mutation to occur and no MET amino acid is made. Each of the four other genes that can be mutated are the MTHFR, MTR, and the MTRR genes. Each of these play a role in converting the homocysteine back to methionine. The mutations in these genes causes the enzyme homocysteine to build up in the body.

A Cure?
Sadly, there is no cure for homocystinuria, however, some measures can be taken to slow down the disease. For example, some people will receive high doses of vitamin Bmedia type="custom" key="8299574" for the rest of their lives, and if they do not respond well to that, they can be put on a highly restrictive diet, with low doses of methionine in it.



Song!
http://www.checkorphan.org/grid/video/homocystinuria-vs-cystinuria/page/7/sort/recent