UROD Gene

The official name of UROD gene is uroporphyrinogen decarboxylase.The UROD gene provides instructions for making anan enzyme called uroporphyrinogen decarboxylase. Uroporphyrinogen III decarboxylase (UroD) is a homodimeric enzyme which catalyzes the fifth step in heme biosynthesis: the elimination of carboxyl groups from the four acetate side chains of uroporphyrinogen III to yield coproporphyrinogen III.Three additional enzymes modify this product before it becomes heme. The heme molecule is then incorporated into hemoglobin and packaged into red blood cells, or it is used in the liver for the production of certain liver enzymes.

Location:

UROD gene is present in human chromosome 1 and ts coded from region 45250417 to 45253928 with 10 exons, the cytogenetic location 1p34.

Disease

Mutations in UROD gene causes a form of porphyria called porphyria cutanea tarda and hepatoerythropoietic porphyria,In porphyria cutanea tarda the mutations occur in one of the two copies of the UROD gene in each cell, which usually reduces the activity of uroporphyrinogen decarboxylase by 50 percent throughout the body.As a result, byproducts of heme production called porphyrins build up in the body, particularly in the liver. This buildup, in combination with nongenetic factors (such as alcohol, smoking, certain hormones, excess iron, and viral infections), causes this type of porphyria.

In hepatoerythropoietic porphyria Most of the mutations are unique in this type of porphyria and have not been found in porphyria cutanea tarda. Mutations that cause hepatoerythropoietic porphyria occur in both copies of the UROD gene in each cell, which reduces the activity of uroporphyrinogen decarboxylase to less than 10 percent of normal. Extremely low levels of this enzyme prevent sufficient amounts of heme from being produced. As a result, byproducts of heme production called porphyrins build up in the body, causing this type of porphyria.