Citrullinemia: Definition, Background, Pathophysiology, Epidemiology


Citrullinemia is a legacy disorder that causes ammonia and other toxic substances to be stored in the blood. Two types of Citrullinemia are described; They have different signs and symptoms and are caused by mutations in different genes.

Type I Citrullinemia (also known as classic Citrullinemia) usually becomes apparent in the first few days of life. Affected infants generally appear normal at birth, but in the form of ammonia, they experience progressive deficiency of energy (lethargy), poor diet, vomiting, seizures, and loss of consciousness. Some affected people develop serious liver problems. Type I Citrullinemia health problems are life threatening in many cases. Less commonly, a lighter form of type i Citrullinemia can develop later in childhood or adulthood. The latter form is associated with the problem with acute headaches, blind spots (scotoma), balance and muscle coordination (Atexia), and lethargy. Some people with gene mutation that cause type I Citrullinemia do not experience the symptoms and symptoms of the disorder at all.

Type II Citrullinemia mainly affects the nervous system, which causes confusion, restlessness, memory loss, abnormal behavior (such as aggression, irritability and excessive activity), seizures and coma. Affected individuals often have specific food priorities, proteins prefer rich and fatty foods, and avoids carbohydrate rich foods. Symptoms and symptoms of this disorder usually appear during adulthood (adult-start) and can be triggered by taking drugs, infection, surgery, and alcohol. In adults with adult-start type II Citrullinemia, these signs and symptoms can be life-threatening.

Adult-start type II Citrullinemia may also develop in those, such as infants who have liver disorder, which is called neonatal intrahepatic cholestasis due to secretion deficiency (NCDD). This liver condition is also called neonatal-type type II Citrullinemia. NICDD blocks the flow of bile (a digestive fluid produced by the liver) and prevents the body from properly processing some nutrients. In many cases, the signs and symptoms of NICDD move within one year. In rare cases, after recovering from NICDD, affected persons have developed other signs and symptoms in early childhood, including delayed increase, extreme fatigue (fatigue), specific food preferences (described above), and blood fat (lipid) Contains unusual amounts of. (dyslipidemia). This condition is known as failure due to citrin deficiency (FTTDCD) and dyslipidemia. After years or even decades, some people with NICDD or FTTDCD develop the characteristics of adult-type type II Citrullinemia.


Type I is the most common form of Citrullinemia disorder, which affects 1 out of 57,000 people worldwide. Type II Citrullinemia is found mainly in the Japanese population, where it is estimated in 100,000 to 230,000 people in 1. Type II is also mentioned in other populations, which includes other people from East Asia, Middle East, United States and the United Kingdom.


Mutation in ASS1 and SLC 25 A13 causes Citrullinemia. Proteins produced from these genes play a role in the urea cycle. The urea cycle is a sequence of chemical reactions that occurs in the liver cells. These reactions process additional nitrogen, which is produced when the protein is used by the body. Extra nitrogen is used to make a compound called urea, which is excreted in the urine.

Mutation in ASS1 gene causes i Citrullinemia This gene provides instructions for making enzyme, argininosuccinate synthase 1, which is responsible for one phase of the urea cycle. Mutation in ASS1 gene reduces the activity of the enzyme, which inhibits the urea cycle and prevents the body from effectively processing nitrogen. Extra nitrogen (as ammonia) and other yields of urea cycle are stored in the blood stream. Ammonia is especially poisonous for the nervous system, which helps to explain neurological symptoms (such as lethargy, seizures, and ataxia), which are often seen in Type I Citrullinemia.

The mutations in the SLC25A13 genes are responsible for adult-start type II Citrullinemia, NICD, and FTTDCD. This gene provides instructions for making a protein called citrin. Within cells, citrin helps in producing molecules of production of simple sugars, proteins, and the production of urea cycles. Molecules transported by citrin are also involved in making nucleotide, which are the construction blocks of DNA and its chemical cousin, RNA. Mutations in SLC 25 A13 genes usually prevent cells from forming any functional citrins, which inhibits the urea cycle and obstruct the production of proteins and nucleotides. Adult-start type II leads to symptoms and symptoms of Citrullinemia as a result of ammonia and other toxic substances. The lack of citrin also has the characteristics of NICDD and FTTDCD, although ammonia is not formed in the blood stream of individuals with these conditions.

Since Citrullinemia is caused by problems with the urea cycle, it is related to a range of genetic diseases called urea cycle disorder.

Heritage Pattern

Both types of Citrullinemia are inherited in an autosomal recessive pattern, which means that copies of the respective genes mutate in each cell. Parents of an automobile recessive condition take a copy of each mutated gene, but they usually do not show signs and symptoms of this condition.

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