OTC gene
The OTC gene provides instructions for making an enzyme critical to the urea cycle, which processes excess nitrogen in the body.
Normal Function
The OTC gene provides instructions for making the enzyme ornithine transcarbamylase. This enzyme participates in the urea cycle, a series of reactions occurring in liver cells. The urea cycle processes excess nitrogen—generated when the body uses protein—into a compound called urea, which is excreted by the kidneys.
Excreting excess nitrogen prevents it from accumulating as ammonia, which is toxic, particularly to the nervous system. The ornithine transcarbamylase enzyme specifically controls the reaction where carbamoyl phosphate and ornithine form a compound called citrulline.
Health Conditions Related to Genetic Changes
Ornithine transcarbamylase deficiency
More than 500 OTC gene mutations have been identified in people with ornithine transcarbamylase deficiency, an inherited disorder that causes ammonia to accumulate in the blood. Because the nervous system is highly sensitive to ammonia, high levels are toxic.
Mutations in the OTC gene result in an enzyme that is shorter than normal, the wrong shape, or prevent any enzyme from being produced. If the enzyme is misshapen or missing, it cannot fulfill its role in the urea cycle. Consequently, excess nitrogen is not converted to urea, leading to the accumulation of ammonia, which causes neurological problems and other symptoms.
Other Names for This Gene
- MGC129967
- MGC129968
- OCTD
- ornithine carbamoyltransferase precursor
- ornithine transcarbamylase
- OTC_HUMAN