Urocanate hydratase deficiency

Overview

Type of disease: Genetic, autosomal recessive | Behavioral and mental health disorders | Rare conditions

Urocanate hydratase deficiency occurs when individuals do not make enough of the enzyme urocanate hydratase, also called urocanase. Enzymes perform important functions in the body. This enzyme’s job is to break down and regulate the levels of urocanic acid. Without this enzyme the body is not able to breakdown urocanic acid and it builds up in the body.

It starts either before birth or during infancy. The build up of urocanic acid causes mental and developmental delays. Individuals also experience ataxia, which is an inability to control one’s muscles. Other symptoms may include sudden outbursts of aggression, anger or a desperate need for affection.

In order to make a diagnosis, a urine sample must be taken from the patient. The medical professional will check for various levels of chemical imbalances; specifically, levels of urocanic acid in the urine are higher than normal in individuals with this disease.

Urocanate hydratase deficiency is a genetic disorder that affects the brain. It results from changes in the UROC1 gene. It is an autosomal recessive condition, which means one mutation from each parent is needed to cause symptoms. A person with only one mutation is called a carrier because they “carry” one changed copy and one unchanged copy of the gene. Carriers also show no signs or symptoms of the condition. If both parents are carriers, each of their children has a one in four chance (25%) of having the condition and a 50/50 chance of being a carrier.

If you or your child has been diagnosed with Urocanate hydratase deficiency, talk to your doctor about current treatment options. Support groups are also good resources for support and information.

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